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Digitized  by  the  Internet  Archive 

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http://www.archive.org/details/geologyofoldhampOOemer 


DEPARTMENT    OF    THE    INTERIOR 


MONOGRAPHS 


OF  THE 


United  States  Geological  Survey 


VOLUME    XXIX 


WASHI^-GTON 

GOVERNMENT    PRINTING    OFFICE 
1898 


io^^*2a 


/ 


Vk . 


UNITED  STATES  GEOLOGICAL  SURVEY 

CHARLES  D.  WALCOTT,  DIRECTOR 


G-EOLOGT 


OF 


OLD  HAMPSHIRE  COUNTY,  MASSACHUSETTS 


COMPRISING 


FRANKLm,  HAMPSHIRE,  AND  HAMPDEN  COUNTIES 


BT 


BElSTJAMlIlSr    KETSTDALL    EMERSON 


WASHINGTON" 

GOVERNMENT    PRINTING    OFFICE 
1898 


CONTENTS 


Letter  of  TRA^SMITTAL xxi 

Chapter  I. — Introduction 1 

Area  covered 1 

Historical  sketcli 2 

Chapter  II. — Topography 8 

Chapter  III. — -Geological  outline  and  general  comparative  sections 12 

General  comparative  section  of  rocks  in  Maasacliusetts ,     16 

Chapter  IV. — The  Algonkian 19 

Geological  description 19 

The  Hinsdale  area 19 

The  Coles  Brook  anticline 21 

The  Tolland  area 24 

Petrographical  description • 24 

Lower  or  Hinsdale  gneiss,  Hinsdale  station 24 

The  Hinsdale  limestone,  Hinsdale 25 

The  Coles  Brook  limestone 27 

The  blue-  quartz  gneiss,  Peru 28 

The  Lee  gneiss 29 

E^sumiS 30 

Chapter  V. — The  Lower  Cambrian  gneisses 31 

The  Becket  conglomerate-gneiss >^ 31 

Contact  u.pon  the  Washington  gneiss  below 31 

Description  of  the  rock 32 

Distribution 33 

Petrographical  description 34 

Crushing  tests 36 

The  gneiss  at  Shelburne 38 

The  Monson  gneiss  and  associated  rocks 41 

The  Pelham  and  Wilbraham  area 42 

The  gneiss 42 

Petrographical  description 43 

The  actinolite-quartzite 45 

Petrographical  description 46 

T 


Vi  CONTENTS. 

Chapter  V. — The  Lower  Cambrian  gneisses — Continued.  Page. 
Tlie  Monson  gneiss — Continued. 

The  Polham  and  Wilbraham  area — Continued. 

Saxonite  and  serpentine  in  Monson  gneiss 47 

•                           The  Pelham  asbestos  quarry 47 

Petrographioal  description 52 

The  Pelham  serpentine 55 

The  Shutesbury  serpentine 55 

The  New  Salem  serpentine 55 

The  Orange  and  Moosou  area 56 

General  description 57 

Petrographical  description 59 

The  Monson  quarry 60 

Strength  of  the  Monson  gneiss 63 

Conglomerate  structure  of  the  Monson  gneiss  and  sudden  expansion  of  the  rock 

in  quarrying 63 

A  complex  mineral  vein  in  the  gneiss 65 

Chapter  VI.— Lower  Silurian  sericite-schists  and  amphibolites  on  the  west  side  of  the  valley.  66 

The  Hoosac  schist  =  the  albitic  mica-schist 66 

The  Monroe  area 67 

The  Middlefield  area 70 

Section  along  the  Boston  and  Albauy  Railroad 71 

Relation  to  the  Becket  gneiss 72 

The  Grranville  area 73 

Hornblendic  bands  in  the  albitic  mica-schist 75 

The  Shelburne  Falls  anticline 75 

The  Eowe  schist^ the  lower  sericite-  or  hydromica-schist 76 

Franklin  County 76 

Hampshire  County - 70 

Hampden  County 77 

Thickness 78 

The  Chester  amphibolite  and  serpentines .    78 

General  description 78 

Franklin  County - 79 

The  Eowe  serpentine 79 

The  East  Portal  fault - 80 

Hampshire  County 81 

The  Middlefield  serpentine - 81 

Hampden  County 85 

The  Chester  amphibolite  and  serpentine 85 

The  Blandford  serpentines  and  pyroxenite 85 

The  Granville  and  Enssell  enstatite-serpentines 90 

The  Westfield  serpentine  and  marble 92 

Faults  and  serpentinization 95 

Petrographical  description 96 

The  amphibolites 96 

The  serpentines  and  associated  magnesian  rocks 97 

Bladed  serpentine ;  antigorite-  (or  bastite-)  serpentine 98 


CONTENTS.  Vll 

Page. 
Chapter  VI.— Lower  Silurian  serioite-schists  and  amphibolites  on  the  west  side  of  the  valley — 

Continued. 

The  Chester  amphibolito  and  serpentines — Continued. 

Petrographical  description — Continued. 

The  serpentines  and  associated  magnesian  rocks — Continued. 

Olivine-  and  enstatite-serpentine 101 

R€8um6 114 

Table  of  analyses  of  serpentines 116 

The  Chester  emery  bed 117 

History  of  discovery  and  working  of  the  bed 117 

A  description  of  the  emery  mine  of  Chester,  Hampden  County,  Massachusetts,  by 

Charles  Upham  Shepard 122 

General  description 135 

Association  and  paragenesis  of  the  minerals  of  the  emery  vein 143 

Re'sumt?  of  paragenesis -  147 

General  explanation  and  correlation  of  the  Chester  amphibolite  series —  147 

Original  condition  of  the  enstatite-serpentine  and  limestone  complex 147 

The  Savoy  schist  =  the  upper  sericite-schist 156 

Distribution 156 

Boundary  upon  the  rocks  below 156 

General  description  of  rocks 157 

Comparison  with  the  Rowe  schist  below ..-  158 

Detailed  description  and  sections 158 

The  Shelburne  anticline 162 

Petrographical  description 162 

Intrusive  rocks - 163 

TheHawley  schist 163 

Distribution 164 

Detailed  description 164 

Petrographical  description 166 

The  possible  igneous  origin  of  the  Hawley  schist 169 

Mineral  deposits 170 

The  pyrite  beds 170 

Copper  ores 171 

The  great  Hawley  fault  and  the  magnetite  and  hematite  deposits,  the  rhodonite  and  rho- 

dochrosite  beds,  and  the  garnet-schist  or  coticule 171 

The  Goshen  anticline 175 

Chapter  VII.  —The  graphitic  mica-schist  series  on  the  west  side  of  the  valley 177 

The  Goshen  schists  or  flags 177 

General  description 177 

Unconformable  contact  on  the  rocks  below ;  outliers  in  the  Hawley  schist 179 

Petrographical  description 181 

The  Conway  schists,  or  the  corrugated  mica-schists 183 

General  description 183 

Subordinate  beds  in  the  Conway  schist 185 

The  gneiss  beds 185 

The  whetstone-schist 186 

Petrographical  description 187 


viii  CONTENTS. 

Chapter  VII. — The  graphitic  mica-schist  series  on  the  -west  side  of  the  valley — Continued.  Page. 
The  Conway  schists,  or  the  corrugated  mica-schists — Continued. 
Suhordinate  beds  in  the  Conway  schist — Continued. 

The  limestone  beds 188 

The  amphibolite  beds 189 

TheConwaybed 189 

The  Whately  bed 190 

The  Whitmores  Ferry  bed 190 

Petrographical  description  of  limestone  and  amphibolite;  the  limestones,  the 

anvils,  passage  of  limestone  into  amphibolite 191 

Analyses  of  the  amphibolites 195 

Projection  of  the  limestone   and  amphibolite  of  the  Conway  schist  through  the 

Leyden  argillite  in  Whately 196 

Contact  metamorphism  of  the  limestone  by  granltite ;  argentine 197 

Cleavage  in  the  Conway  schists 199 

Fossils  (?)  of  the  Conway  schists 200 

The  Leyden  argillite 201 

Description 201 

Quartzite  in  the  argillite 202 

Petrographical  description 202 

Stratigraphy 203 

Boundary  on  the  Conway  schists 203 

Argillite  on  the  western  border  of  the  ' '  graphitic  mica-schist "  (Goshen  schist) 204 

Relative  .age  of  the  Conway  schist  and  the  Leyden  argillite 204 

Contact  metamorphism  of  the  Leyden  argillite  bordering  the  tonalite  of  Hatfield..  205 

The  sericite-gneiss 206 

The  chiastolite-schist 209 

Chapter  VIII. — The  bands  of  Silurian  schists  on  the  east  side  of  the  valley 211 

The  Northfield  semisyncline ■- 212 

General  description 212 

The  Gulf  road  sections 213 

Sections  north  and  south  of  the  old  Warwick  road 215 

Pegmatite  dikes  and  minerals - 216 

The  Wendell  branch  syncline 217 

The  Leverett-Amherst  area 218 

The  amphibolite  and  mica-schist  series  along  the  east  side  of  the  Connecticut  basin  from 

Leverett  southward 218 

North  Leverett  (Greenfield  quadrangle,  southeast  comer) 219 

Leverett  Center — .  220 

The  Savoy  schist,  or  whetstone-schist 220 

The  Amherst  feldspathic  mica-schist  (Conway  schist) 222 

Leverett 222 

Amherst — 222 

The  Pelham-Shutesbury  syncline 225 

The  great  central  syncline 227 

Warwick  and  Orange 227 

Topography 230 


CONTENTS.  IX 

C'liAi'iKK  VIII. — Tbr  biinils  ofSiluriuu  sc-hists  ou  the  east  side  of  the  valley — Continued.  Ta^c 
The  great  central  syucline — Coutiuued. 

.South  Oranyo  and  Now  Salem 230 

I'rescott  and  Knfleld 232 

Structure 232 

Petrographical  descriptions 233 

The  eastern  sy ncline 234 

Orange  and  Athol 234 

General  description 234 

Metamorphism  of  the  amphibolite  hand  as  it  is  involved  in  the  grauitite  of  the 

Athol  hatholite,  and  its  later  change  to  steatite 236 

Ware 237 

General  description 237 

Petrographical  description 238 

The  Hardwick  gneiss 239 

Petrographical  description 240 

Palmer 241 

Monson - 241 

The  zone  of  contact  around  the  Belchertown  tonalite 243 

The  pyroxenic  amphiholites 243 

The  fibrolite-schist  inclusions 246 

Petrographical  description 246 

The  Wilbraham  syncline 248 

The  Monson  syncline 249 

The  East  Greenwich-Enfield  syncline 251 

Efeum6 251 

Argument  for  the  identity  of  the  schist  series  east  of  the  Connecticut  with  those  ou  the 

west 251 

The  passage  eastward  into  the  Brimfield  fibrolite-schist 252 

Chapter  IX. — The  Bernardston  series  of  Upper  Devonian  rocks 253 

Literature 253 

History 254 

Upper  Devonian  age  of  the  Bernardston  fossils 259 

Description  of  the  region 260 

The  relation  of  the  Bernardston  series  to  the  argillite 261 

The  AVilliama  farm  section;  the  fossiUferous  limestone;  proof  that  the  whole  series  is 

Devonian 262 

Description  of  the  range  from  Bernardston  to  South  Vernon 272 

The  feldspathic  quarfczite  282 

The  Bernardston  series  east  of  the  Connecticut 284 

The  original  character  of  the  series  and  its  metamorphism 285 

Petrographical  description 287 

The  quartzite  series 287 

Amphibolite  associated  with  the  limestone  in  the  gneissoid  quartzite 290 

The  mica  and  amphibolite  series - 291 

Rooks  at  the  mouth  of  Millers  Eiver 295 


X  CONTENTS. 

Page. 

Chapter  X.— The  ampliibolites  described  in  the  preceding  chapters 300 

Analyses  and  sections ^'"' 

Porphyritic  character  of  the  amphibolites 304 

Chapter  XI. — The  eruptive  rocks 307 

Introduction 3"' 

Historical  notes  on  the  mica-granites 312 

Biotite-muscovite-gran  ito ^^^ 

Areas  west  of  the  Connecticut 31'^ 

Distribution ^1* 

Petrographlcal  description ■'^l^ 

Chemical  analysis 315 

The  Athol  area 316 

Secretions  and  inclusions 317 

The  Hardwick  gneissoid  granite  and  granitlte 317 

Biotite-granite,  or  granitite 318 

Contact  metamorphism  of  the  granitite  and  schists 318 

The  Middlefield  porphyritic  granitite 318 

The  Coy's  Hill  porphyritic  granitite 319 

Description  and  distribution 319 

Cordierite-granitite 321 

Muscovite-granite,  or  pegmatite 322 

Probable  extreme  modification  of  the  pegmatite  by  crushing 323 

Albitic  granite  and  pegmatite  dikes  containing  rare  minerals 323 

Distribution  and  description 324 

The  great  tonrmaline-spodumene  dike  324 

Dikes  in  Goshen 3-'6 

Dikes  in  Chester,  Blandford,  and  Huntington 327 

Dikes  east  of  the  Connecticut 327 

Garnet  in  pegmatite  with  complex  paramorphic  border  of  zoisite-hematite,  epidote- 

fibrolite,  and  muscovite 3-^8 

The  crushing  of  minerals  in  the  albitic  granite 329 

Hydrothermal  changes  in  the  albitic  granite  veins 329 

Ordinary  meteoric  alteration 330 

Aplite - 331 

Quartz-gabbro  and  quartz-diorite,  or  tonalite 331 

Historical 331 

Basic  secretions :  Hitchcock's  suggestion  of  the  theory  of  "  schlierengUnge  " 331 

Distribution 335 

Analyses  of  tonalite 336 

Petrographical  description 336 

The  crushing  and  alteration  of  the  tonalite  along  the  Pelham  fault 339 

Petrographical  description  of  the  altered  tonalite 341 

Diorite 342 

Garnet-biotite-norite 

Cortlandite 346 

QAQ 

Age  of  the  granites 

Resume  as  to  the  genetic  relations  of  the  granites 348 

Contact  effects  of  the  eruptive  rocks 349 


CONTENTS.  XI 

Page. 

Chaptbr  XII.— Tlio  Trias ■ 3.51 

The  Coniiocticut  Rivoi-  sandstono 3.51 

General  section  of  Triassic  rocks 354 

The  Sugar  Loaf  arkose,  or  the  feldspathlc  sandstone  and  conglomerate 354 

Contact  and  distribution 355 

The  Mount  Toby  conglomerate,  or  the  slate  and  quartzite  conglomerate 358 

Contact  and  distril>ution 358 

The  outcrops  of  crystalline  rocks  in  the  midst  of  the  Mount  Toby  conglomerate  ...  361 

Action  of  ice  in  the  Trias 363 

The  Longmeadow  sandstone 364 

Fragments  of  white  trap  without  augite  in  the  sandstone  above  the  Holyoke  sheet.  365 
Disturbances  in  the  sandstones  and  inclusions  of  trap  fragments  just  below  the 

posterior  sheet 367 

The  boundary  of  the  sandstone 368 

Analyses 369 

The  Granby  tuff,  or  the  diabase-tuff 369 

The  Chicopee  shale,  or  the  calcareous  shale 370 

The  continuation  of  the  State-line  fault  in  a  crushed  band  at  the  Holyoke  dam  and  the 

secondary  minerals  found  in  the  fissures 370 

The  diabase 372 

The  formation  of  the  basin  and  the  distribution  of  the  sediments  by  strong  tidal  currents..  372 

The  possible  connection  of  the  foot  tracks  with  the  trap  sheets 379 

Artesian  wells - 380 

Pseudomorphs  of  caloite  and  dolomite  after  hopper-sh  aped  cubes  of  salt 389 

The  use  of  the  Triassic  sandstone  as  a  building  stone 391 

Paleontology 394 

Plants 394 

Insects 398 

Fishes 398 

Ichnology '*^'^ 

Eecent  progress  in  Ichnology,  by  C.  H.  Hitchcock 400 

Reptiles *05 

Chapter  XIII. — The  Triassic  eruptive  rocks '107 

Historical '^07 

The  three  epochs  of  eruptive  activity ;  general  account 4:10 

Diabase  dikes  and  stocks  in  the  gneiss  east  of  the  Trias *ll 

A  microscopical  diabase  dike  from  Pelham,  and  olivine  and  glass-bearing  dikes  from 

Monson - *1° 

The  bedded  or  contemporaneous  eruptives '^^° 

The  Deerfield  sheet - ^^^ 

Contact  on  the  sandstone  below;  the  underrolling  of  the  crust  and  the  alteration  of 
the  diabase  by  heated  waters  to  a  pitchstone-breccia  and  a  diopside-plagioolase 

rock '^^^ 

General  character 4-^4 

Greenfield  quarry  exposures  and  contacts - ^"^ 

Petrographical  description 43^ 

Diabase-pitchstone ^32 


XU  CONTENTS. 

Chapter  XIII. — The  Triassic  eruptive  rooks — Continued.  Page. 
The  bedded  and  contemporaneous  eruptives— Continued. 
The  Deerfield  sheet — Continued. 

Contact  on  the  sandstone  below,  etc — Continued. 
Petrographical  description — Continued. 

Glass-breccia 433 

Anygdaloidal  sandstone 435 

Contact  material 436 

LithophysEB 436 

Chemical  discussion 436 

Origin  of  the  glass  and  minerals 437 

Contact  of  the  sandstone  upon  the  diabase 439 

Fall  River  fault 439 

The  unity  of  the  sheet 440 

Petrographical  description 441 

Paragenesis  of  secondary  minerals 444 

The  Holyoke  sheet 446 

The  faults  at  Jfount  Tom  and  southward 449 

General  characteristics  of  the  sheet 451 

Normal  contacts  of  diabase  on  sandstone 452 

Contacts  of  underroUed  diabase  inclusions  of  limestone 452 

Petrographical  description 453 

Normal  contact  of  the  sandstone  on  the  diabase 455 

Contacts  of  sandstone  on  diabase  which  is  kneaded  full  of  limestone  and  shale 456 

Section  of  trap  filled  with  limestone  fragments  on  the  Westfield-Holyoke  Railroad. .  456 

Magmatic  differentiation 459 

Origin  of  the  clay  and  marl  deposits 459 

On  the  uuderroUiug  of  the  solidified  surface  of  the  trap 460 

Petrographical  description  of  the  normal  diabase 461 

Chemical  composition  of  the  trap 463 

The  upper  or  posterior  sheet  and  its  feeding  dikes 464 

The  great  widening  of  the  trap  area  and  the  feeding  throat  beneath 467 

Sills  intruded  in  the  sandstones  below  the  posterior  sheet 469 

Delaney 's  quarry,  near  the  north  line  of  Holyoke 470 

The  Roaring  Brook  fault  and  the  disappearance  of  the  posterior  sheet 473 

The  blending  of  the  tuff  with  the  surface  of  the  posterior  bed 474 

A  tufiTaceous  sandstone  containing  white  trap 474 

The  posterior  dike  across  Hampden  County 475 

The  Talcott  sheet 476 

The  tuff  and  tuffaceous  agglomerates 476 

The  Deerfield  bed 476 

TheGranbybed 476 

The  isolated  mass  of  tuff  north  of  the  seventh  core 479 

Source  of  the  material  of  the  tuff  bed 480 

A  hollow  bomb  from  Delaney's  quarry,  Northampton 480 

Petrographical  description 480 

The  newer  series  of  cores  and  short  dikes 481 


CONTENTS.  Xiii 

Chapter  XIII. — The  Triassic  eruptive  rocks — Continueil.  Page. 
Tlie  newer  series  of  cores  and  short  dikes — Continued. 

Belchortown 481 

Grauby 482 

South  Hadley 483 

The  ninth  core  of  diabase,  with  granitic  inclusions 483 

Petrographical  description 484 

The  eleventh  or  Black  Rock  core 489 

Petrographical  description 492 

Northampton 494 

Summary  of  the  history  of  the  Connecticut  River  sandstone 49.5 

The  use  of  the  trap  as  road  material 500 

Chapter  XIV. — Mineral  veins  502 

Chapter  XV. — The  Pleistocene  period 508 

Literature 508 

The  interval  between  the  Triassic  and  the  Glacial  period 508 

Deposits 508 

Pre-Glacial  weathering 509 

Pre-Glacial  drainage  and  erosion 510 

Pre-Glacial  course  of  the  Connecticut  and  Its  tributaries 513 

Character  and  amount  of  the  erosion  during  later  Mesozoic  time  as  compared  with  that 

of  the  Glacial  period 515 

Chapter  XVI.— The  Glacial  period 518 

The  present  rook  surface  and  the  amount  of  Glacial  and  post-Glacial  material  on  the  same. .  518 

Glacial  grooves  and  striae 522 

Glacial  notches 529 

Pseudo-glacial  strise  on  Devonian  argillites 531 

Potholes 532 

Thetm 533 

Introduction 533 

The  upland  drift 535 

The  fine  valley  drift  of  the  east  side  of  the  valley 537 

The  coarse  valley  drift 541 

Distribution  of  the  coarse  valley  till  west  of  the  river 542 

Drumllns 543 

Moraines  and  bowlder  trains 549 

Interglacial  sands  .  - : 550 

The  upper  till 558 

Remarkable  bowlders 559 

Chapter  XVII. — The  Champlain  period 562 

Glacial  lakes  east  of  the  Connecticut  River 562 

Introduction 562 

Ice  barriers 565 

The  Brlmfield  Lake 565 

The  Monson  esker 566 

The  Monson  drainage 567 

The  eastern  Palmer  and  Monson  Lake 567 


Xiv  CONTENTS. 

Chapter  XVII. — The  Champlain  period — Continued.  Page. 
Glacial  lakes  east  of  the  Connecticut  Eiver — Continued. 

The  Ellis  Mills  drainage 569 

The  Palmer  Lake 569 

The  Ware  and  Swift  Eiver  lakes 569 

The  Chicopee  Eiver  drainage 575 

The  Belcherto wn  Lake 575 

The  Pelham  Lake  and  esker 578 

The  Iladley  Lake  drainage 584 

The  Leverett  Lake  and  the  Notch  east  of  Mount  Toby 584 

The  Locks  Pond  Lake 588 

Notches  through  the  Holy oke  range  and  the  range  north  of  Moody  Corners 586 

TheGranby  Eoad  Lake 587 

The  Notch 587 

The  low  place  and  Moody  Corners  Lake 587 

The  Pelham  Eiver  and  the  "Moraine  Terrace"  sands  along  the  eastern  valley  side,  just 

above  the  level  of  the  high  terrace 588 

The  Sunny  Valley  Lake 592 

The  sands  along  the  west  side  of  Mount  Tom  Eange  and  in  the  Westfield  basin 

above  the  level  of  the  high  terrace 592 

Chapter  XVIII.— The  Champlain  period  (Continued) 593 

Glacial  lakes  west  of  the  Connecticut  Eiver 593 

The  Granville  Lake 593 

TheNorth  Granville  Lake 593 

The  Westhampton  Lake 594 

The  Williamsburg  Lake 595 

The  Beaver  Brook  Lake  above  Leeds 595 

The  Deerfield  Eiver  lakes 595 

The  Deerfield  Eiver  and  its  tributaries  on  the  north ■- 597 

The  Conway  Lake 598 

The  Bear  Eiver  Lake ---  600 

The  Ashfield  Lake 601 

The  Buckland  Lake 602 

The  last  important  halting  place  of  the  ice  front  across  the  basin  of  the  Deerfield  Eiver.  604 

Glacial  lakes  north  of  the  Deerfield  Eiver 604 

High  level  deltas 605 

The  character  of  the  terraced  flood  deposits  of  the  Westfield  Eiver 607 

Chapter  XIS. — The  Champlain  period  (Continued) 609 

The  Connecticut  Eiver  lakes 609 

Introduction 609 

Detailed  description  of  the  flood  deposits  in  the  Montague  basin 615 

The  northern  lobe  of  the  lake , 616 

The  Bennetts  Brook  plain,  or  moraine  terrace 617 

The  extension  of  the  flood  gravels  westward  through  the  Bernardston  Pass 619 

The  old  course  of  Fall  Eiver 621 

The  bench  on  the  east  side  of  the  river  in  Northfield  and  Erving 622 

The  Millers  Eiver  delta ;  the  canyon  and  old  course  of  the  Connecticut 625 


CONTENTS.  XV 

Chapter  XIX. — The  Chiimplaiu  })orio(l — Continued.  Page. 
The  Conuectiout  River  lakes — Continued. 

The  Iliidley  Lake g29 

The  uortli  end  of  the  lake  in  Greenfield  and  the  channel  of  connection  with  the  main 

valley 629 

The  Green  River  glacier 630 

The  Factory  Village  channel 632 

The  high  terrace  plains  in  the  south  of  Greenfield  and  the  north  of  Ueerfield 632 

The  lake  bench  from  Deertield  River  south 634 

The  Deerfield  delta 634 

The  West  Brook  delta 635 

The  Mill  River  delta  in  Northampton 637 

The  lake  hench  on  the  east  side  of  Hadley  Lake  in  Leverett  and  Amherst 639 

The  delta  of  Cushmans  Brook  at  North  Amherst  and  the  isolation  of  the  East 

Street  hasin  in  Amherst 640 

The  hench  surrounding  the  East  Street  basin 641 

Shore  notches  in  the  sides  of  drumlins 642 

The  high  terrace  or  bench  along  the  west  side  of  the  Amherst  ridge 644 

The  bench  around  Mount  Warner 648 

The  bench  along  the  north  slope  of  the  Mount  Holyoke  and  Mount  Tom  range 649 

The  Westfield  plain 650 

The  greater  elevation  of  the  terraces  in  the  Westfield  than  in  the  Springfield  Lake ; 

possible  western  elevation 654 

Geology  of  Westfield  and  vicinity,  by  J.  S.  Diller 654 

The  Springfield  Lake 657 

The  "gorge  terrace"  of  Dry  Brook  Hill  in  the  north  part  of  South  Hadley 661 

The  high  terrace  of  the  west  side  of  the  river  from  the  Holyoke  notch  southward  . ,  662 

The  similarity  of  the  Belchertown  notch  to  the  notch  east  of  Mount  Toby 663 

The  moraine  across  the  southern  part  of  the  Granby  plain 664 

Kettle  holes  and  the  old  bed  of  the  Connecticut i 664 

Kettle  holes  and  the  structure  of  the  high-terrace  sands;  their  origin  from  the  melting 

of  ice  beneath  the  terrace  gravels 665 

Lake  bottoms 672 

The  Montague  Lake 672 

The  Hadley  Lake 673 

The  Springfield  Lake 677 

Detailed  sections  of  terraces  and  lake  bottoms,  showing  several  advances  of  the  ice 

front _ _ .,...' _  677 

The  Camp  Meeting  cutting 677 

Section  of  clays  in  Hatfield,  showing  great  disturbance  and  pressure  cleavage 691 

The  Wapping  cutting ; 695 

Chaptek  XX.— The  Champlain  period  (Continued) 69? 

The  Champlain  clays 697 

Introduction 697 

The  Montague  Lake 697 

The  Hadley  Lake 698 

The  Springfield  Lake 701 

Contact  of  the  clays  upon  the  till 701 


xvi  CONTENTS. 

Chapter  XX. — The  Champlain  period — Continued.  Page. 
The  Champlain  clays — Continued. 

The  Springfield  Lake— Continued. 

The  structure  of  the  clays 703 

The  surface  of  the  layers 704 

The  lateral  passage  of  the  clays  into  the  high  terrace  sands 705 

The  passage  of  the  clays  into  the  sands  above 705 

Explanation  of  the  structure  of  the  clays 706 

The  time  occupied  in  the  deposition  of  the  clays 707 

Action  of  icel)erg8  and  floes  upon  the  clays 707 

Secondary  structures  in  the  clays 709 

Joints 709 

Concretions - 711 

Fossils  of  the  Champlain  clays 718 

Chapter  XXI. — The  terraces  of  the  Connecticut  and  the  modern  deposits 722 

Introduction 722 

The  intermediate  terrace  and  harrier  at  Lily  Pond  in  Gill;  an  abandoned  waterfall 724 

The  low-level  terraces  and  flood  plain  of  the  Connecticut  in  the  basin  of  the  Montague  Lake.  725 

The  later  terraces  or  meadows  of  the  Connecticut  in  the  Hadley  Lake 726 

The  structure  of  the  terraces 727 

The  river  sands 727 

The  muck  sands 728 

The  peat  deposits  and  the  plant  remains 728 

Loess 729 

The  terraces  of  the  Connecticut  in  the  Springfield  basin 729 

The  incomplete  terraces  as  illustrations  of  the  stages  in  the  growth  of  terraces 731 

On  the  oscillations  of  the  Connecticut  from  its  earliest  position 733 

The  oxbows  of  the  Connecticut 734 

On  the  deflection  of  streams  toward  the  right  hank 734 

Eiver  terraces  around  a  receding  waterfall 735 

The  terraces  of  tributaries 736 

An  old  oxbow  of  Fort  Eiver 737 

Fossils  of  the  terrace  period 738 

The  Pleistocene  beetles  of  Port  Eiver,  Massachusetts,  by  S.  H.  Scudder 740 

The  repulsion  of  tributaries 746 

Dunes  and  wind  loess 747 

Mineral  springs - 749 

Thick  modern  fissure  deposits  of  quartz  surrounding  roots  in  the  base  of  the  Holyoke  trap 

sheet.   752 

Chapter  XXII. — Supplement  to  the  author's  mineral  lexicon  of  Franklin,  Hampshire,  and 

Hampden  counties 754 

Chapter  XXIII. — Chronological  list  of  publications  on  the  geology  and  mineralogy  of  Frank- 
lin, Hampshire,  and  Hampden  counties 762 

Index 783 


LLUSTRATIONS, 


Page. 
Plate  I.  Coign  of  Williston  Hall  at  Amherst  College,  sbowiug  conglomerate-gneiss  from  the 

Mouson  (luarry 64 

II.  Thin  sections 106 

Fig.  1.  Sahlite  changing  to  tremolite 106 

2.  Dolomite  changing  to  serpentine 106 

3.  Enstatite  crystal  altered  to  serpentine,  cut  parallel  to  (001 ) 106 

4.  Garnet,  with  complex  border,  from  pegmatite 106 

III.  Thin  sections , 208 

Fig.  1.  Leydeu  argillite  changed  to  chiastolite  schist  in  contact  on  tonalite 208 

2.  Covdierite  twins,  frohi  cordierite-granite 208 

3.  Diorite,  from  Packards  Mountain,  Prescott 208 

4.  Contact  of  diabase-amygdaloid  and  clayey  limestone 208 

IV.  Map  of  the  Devonian  rocks  of  the  Bernardston  series  and  of  the  fanlted  syuclini'.  of 

Silurian  schist  in  Northfleld  Mountain 260 

V.  Sections  of  amphibolites  derived  from  limestone 302 

VI.  Sections  of  amphibolites  probably  derived  from  limestone 306 

VII.  Tourmaline  dendrites  in  granite,  Leeds 316 

VIII.  Vertical  wall  of  diabase  at  the  quarry  for  road  material  in  the  east  of  Greenfield 424 

Villa.  Details  of  trap  ridge  east  of  Greenfield 426 

VIII6.  Inclusion  of  mud  in  upper  surface  of  trap  sheet 428 

VIIIc.  Thin  sections  of  material  from  Greenfield  and  Meriden  "ash  bed" 430 

IX.  Geological  map  and  sections  of  the  Mount  Holyoke-Mount  Tom  range,  with  the  pos- 
terior diabase  sheets,  the  tuff,  and  the  A'olcanic  cores 446 

X.  Batterson's  quarry,  in  north  part  of  South  Hadley,  showing  veneering  of  sandstone 

on  Black  Rock  core 488 

XI.  Map  of  preglacial  -drainage  and  drift  strite 510 

XII.  Sections  in  Amherst  House  cellar,  showing  interglacial  beds 550 

XIII.  The  great  serpent  esker  in  Pelham 578 

XIV.  Diagram  of  the  lake-shore  and  lake  bottom  profiles  of  the  Connecticut  lakes 656 

XV.  Sections  at  the  Camp  Meeting  cutting,  on  the  north  line  of  Northampton,  showing  the 

readvances  of  the  glacial  ice. 678 

XVI.  Surface  of  ice-contorted  clay,  smoothly  cut  with  a  knife,  east  of  J.  Ryan's  house,  Hat- 
field   - 690 

XVII.  Joints  and  faults  in  laminated  clay,  produced  by  the  weight  of  the  ice 692 

MON  XXIX ii  s;vii 


Xviii  ILLUSTBATIONS. 

Page. 

Pl.  xviii.  The  Wapping  and  Camp  Meeting  cuttings 694 

Fig.  1.  Section   of  ane-graiued  contorted  sands  at  the  Wapping  cutting    on  the 

Canal  Kailroad,  in  Deerfield 694 

2.  Section  on  the  west  side  of  the  Camp  Meeting  cutting 694 

3.  Detail  from  point  above  (i  on  Plate  XV,  below  fourth  ice-worn  surface 694 

XIX.  Champlain  clays,  distorted  by  floe  ice,  Northampton  708 

XX.  Calcareousconcretionswith  wormtracks,Champlainclays,HadleyandNorthampton. .  716 
XXI.  Profile  of  the  Connecticut  Eiver  from  Vernon,  Vermont,  to  Hartford,  Connecticut, 

showing  high  and  low  water  and  the  river  bottom. 722 

XXII.  View  across  the  Connecticut  Eiver,  showing  the  notches  formed  by  the  river  at  the 

Lily  Pond,  in  Gill,  and  its  escape  around  The  Narrows 724 

XXIII.  Pleistocene  beetles  of  Fort  Eiver,  Massachusetts;  S.  H.  Scudder 742 

XXIV.  Geological  sections  along  Hues  I  to  IV,  dj'awn  on  the  northwestern  portion  of  the 

generalmap  (PI.  XXXIV) 782 

XXV.  Geological  sections  along  lines  V  to  VIII,  drawn  on  the  western  portion  of  the  general 

map  (PI.  XXXIV) 782 

XXVI.  Geological  sections  along  lines  IX  to  XII,  drawn  on  the  southwestern  portion  of  the 

general  map  (PI.  XXXIV) 782 

XXVII.  Geological  sections  along  lines  XIII  to  XVI,  drawn  on  the  northern  portion  of  the 

general  map  (PI.  XXXIV) 782 

XXVIII.  Geological  sections  along  lines  XVII  to  XIX,  drawn  on  the  central  portion  of  the 

general  map  (PI.  XXXIV) 782 

XXIX.  Geological  sections  along  lines  XX  to  XXIII,  drawn  on  the  southern  portion  of  the 

general  map  (PI.  XXXIV) 782 

XXX.  Geological  sections  along  liues  XXIV  to  XXVII,  drawn  on  the  northeastern  portion 

ofthe  general  map  (PI.  XXXIV) 782 

XXXI.  Geological  sections  along  lines  XXVIII  to  XXXII,  drawn  on  the  eastern  portion  of 

the  general  map  (PI.  XXXIV) 782 

XXXII.  Geological  sections  along  lines  XXXIII  to  XXXVI,  drawn  on  the  southeastern  por- 

tion of  the  general  map  (PI.  XXXIV) : 782 

XXXIII.  "Anvils,"  formed  by  the  unequal  erosion  of  blocks  of  impure  limestone  (plate 

wrongly  numbered) 1"2 

XXXIV.  Geological  map  of  Franklin,  Hampshire,  and  Hampden  counties In  pocket 

XXXV.  Map  of  the  .surface  geology In  pocket 

Fig.    1.  Algonkian  section  at  Coles  Brook 22 

2.  Detailed  section  of  the  limestone  at  Coles  Brook 23 

3.  Southwest  wall  of  Pelham  asbestos  quarry  in  1890 4:8 

4.  West  wall  of  Pelham  asbestos  quarry 4:9 

5.  Section  at  Osborn's  soapstone  quarry,  Blandford 87 

6.  Map  of  emery  veins  in  epidote-amphibolite  at  north  end  of  bed  on  the  bank  of  the 

Westtield  Eiver,  Chester 136 

7.  Section  of  old  emery  mine,  Chester - 141 

8.  Stellate  marble;  Westtield  Marble  Company's  quarry,  Eussell 152 

9.  Plan  of  altered  dikes  and  quartz  veins  in  chlorite-schist,  Charlemont 169 

10.  Contorted  layer  of  garnetiferous  quartzite  (coticule),  from  mine  on  Forge  Hill,  Hawley. .  174 

11.  Map  showing  the  protrusion  of  the  limestone  ofthe  Conway  schist  through  the  Leyden 

argillite,  Whately 1^^ 


ILLUSTRATIONS.  XIX 

Pago. 

Fig.  12.  Surface  of  h\ark  limestone  with  oolltol■t(^(l  (juarfcz  voins,  Wliately. '. V.W 

13.  Section  ou  lailinad  oast  of  Erving  station ^17 

14.  Section  of  schists  west  of  Belchoitown 244 

15.  Map  of  Devonian  locks  on  the  Williams  farm,  Bernardston 263 

16.  Section  of  Devonian  rocks  from  the  Williams  farniliouse  250  rods  northwest 264 

17.  Section  of  the  Williams  farm  quarry 264 

18.  Section  at  uortli  cud  of  limestone,  Williams  farm 266 

19.  Section  across  Bernardston  series  on  Purple  blind  road,  Bernardston 278 

20.  Sketch  uuip  of  rocks  near  the  mouth  of  Millers  River,  Erviiig -  - .  295 

21.  Sketch  of  rocks  at  mouth  of  Millers  Eiver,  looking  northeast  from  B,  iig.  20 295 

22.  Section  on  east  bank  of  the  Connecticut  above  mouth  of  Millers  Eiver,  at  A,  fig.  20 .  --  296 

23.  Section  at  the  Holyoko  dam,  showing  the  passage  of  a  fault  through  the  shales 371 

24.  Thin  sections  of  sand  and  glass  breccia  from  the  base  of  the  Greenfield  sheet  at  the 

City  quarry  and  of  trap  from  Cheapside 422 

25.  View  of  the  posterior  trap  sheet  and  its  feeding  dike  at  Little  Mountain,  in  Forest 

Park,  Northampton ^66 

26.  Section  of  Uelaney's  quarry  on  the  Connecticut  Eiver  Eailroad  in  Northampton,  near 

north  line  of  Holyoke 4:70 

27.  Section  of  contact  of  Black  Rock  plug  and  the  Mount  Holyoke  diabase  bed 490 

28.  Holyoke  notch  from  Hadley  meadow ;  pre-Glacial  rock  terr.aces 510 

29.  Glacial  groove  on  compact  diabase,  Prospect  House,  Mouut  Holyoke 527 

30.  East  slope  of  a  large  glaciated  groove  behind  the  bowling  alley  on  Mount  Holyoke 530 

31.  Section  showing  the  striai  on  the  surface  of  sandstone  continued  on  the  surface  of  the 

till,  Hoe  Factory,  Northampton 540 

32.  Pelhnui  Lake  section 578 

33.  Section  of  terminal  moraine  covered  by  high-level  flood  gravels  of  Westfield  River,  at 

Russell - 607 

34.  Sand  bowlders,  in  terminal  moraine,  crushed  by  the  ice  while  frozen 607 

35.  Section  throiigh  the  eroded  front  of  the  great  delta  at  Montague  City 629 

36.  Section  of  the  Green  River  delta  at  north  end  of  Green  River  basin 631 

37.  Section  of  the  shore  beds  of  Hadley  Lake  south  of  College  Hill,  Amherst 646 

38.  Enlarged  section  of  the  south  side  of  the  cutting  shown  in  fig.  37 647 

39.  Detail  of  clay  layer  crumpled  by  the  current,  from  fig.  38 648 

40.  Sections  south  of  Millers  Falls  station,  showing-  kettle-holes  formed  by  ice  melting 

from  beneath  the  sands - 666 

41.  Section  south  of  Millers  Falls,  showing  kettle-hole  formed  by  ice  stranded  ou  the  sur- 

face of  the  sands 668 

42.  Section  of  north  half  of  kettle-hole  below  D wight's  station,  Belchertown 669 

43.  Section  at  the  south  end  of  North  Pond,  Belchertown,  showing  part  of  a  kettle-hole  at 

the  north  end  and  of  an  erosion  slope  at  the  south  end 670 

44.  Section  of  kame  sands  at  the  north  end  of  the  "  big  fill,"  south  of  Itwight's 671 

45.  Block  of  frozen  "pink  sand,"  showing  fine  system  of  joints - 681 

46.  Pharyngeal  hone  of  a  fish,  from  the  Champlain  clay,  Holyoke 721 

47.  Sketch  of  the  point  of  the  Northampton  meadow  from  Mount  Holyoke.  showing  that 

the  meadow  is  a  composite  of  many  islands 726 

48.  An  old  oxbow  of  Fort  River  cut  by  the  Connecticut  below  Hadley 737 


LETTER  OF  TRANSMITTAL. 


Amherst  College, 
Amherst,  Mass.,  March  4,  1895. 
Sir:  I  have  the  honor  to  transmit  herewith  the  manuscript  of  a  geo- 
logical description  of  the  three  counties  in  Massachusetts  through  which  the 
Connecticut  River  runs,  and  which  include  nearly  the  whole  of  that  por- 
tion of  its  drainage  area  which  lies  within  the  limits  of  the  State. 

The  studies  here  presented  began  in  1873.  The  results  were  offered  to 
the  United  States  Greological  Survey  in  1887,  and  were  accepted  at  that 
time.  A  small  portion  of  the  area  has  since  been  reexamined,  under  the 
direction  of  the  Survey,  and  the  map  has  been  extended  a  Httle  beyond  the 
limits  of  the  State  north  and  south,  to  cover  the  whole  of  the  area  repre- 
sented on  the  topographic  sheets  employed.  In  this  work  I  have  been 
assisted  by  Mr.  William  Orr,  jr.,  of  Springfield,  who  has  mapped  part  of  the 
limestone  and  amphibolite  bands  of  the  Conway  schist,  and  by  Mr.  Fred- 
erick B.  Peck,  who  traced  the  western  boundary  of  the  Shelburne  anticline 
and  worked  on  the  southern  border  of  the  area  mapped  on  the  Granville 
sheet. 

As  the  work  was  mostly  done  before  the  appearance  of  the  topographic 
maps  issued  by  the  Sm-vey,  many  allusions  to  names  found  upon  county 
atlas  maps  remain. 

Very  respectfully,  your  obedient  servant, 

B.  K.  Emerson, 

Geologist. 
Hon.  Charles  D.  Walcott, 

Director  United  States  Geological  Survey. 


GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASSACHUSETTS,  COM- 
PRISING FRANKLIN,  HAMPSHIRE,  AND  HAMPDEN  COUNTIES. 


By  Benjamin  Kendall  Emerson, 
Pkofessor  of  Geology  in  Amherst  College. 


CHAPTER    I. 

INTRODUCTION. 

AKEA  COVERED. 

Old  Hampshire  County,  which  formerly  stretched  across  the  State  of 
Massachusetts  between  Berkshire  on  the  west  and  Worcester  on  the  east, 
has  been  less  fortunate  than  these  and  has  lost  Franklin  County  on  the 
north  and  Hampden  on  the  south.  Amherst  lies  in  the  center  of  this  area, 
and  hence  it  has  come  about  that  for  many  years  the  region  has  been 
the  field  of  my  geological  studies. 

The  rocks  strike  north  and  south  and  run  quite  across  New  England 
and  beyond,  so  some  artificial  limits  had  to  be  chosen  in  these  directions, 
and  the  limits  of  the  State  were  as  convenient  as  any.  On  the  east  and 
west,  the  area  lying  between  the  plateau  of  Worcester  County  on  the  east 
and  the  full  development  of  the  Berkshire  Hills  country  on  the  west  pos- 
sesses a  good  degree  of  geological  unity,  the  Cambrian  gneiss  of  its  eastern 
and  western  boundaries  being  almost  certainly  continuous  beneath  the  whole 
area  and  supporting  several  series  of  schistose  rocks,  which  cidminate  in  the 
Bernardston  highly  metamorphosed  but  fossiliferous  beds  of  Devonian  age. 
The  area  includes,  also,  the  northern  half  of  the  Triassic  terrane,  which 
reaches  nearly  to  the  north  line  of  the  State,  while  the  sudden  widening  of 
the  valley  of  the  Connecticut  just  at  this  northern  point,  with  the  lowering 

MON  XXIX 1  1 


2         GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

of  its  borders,  occasions  a  much  greater  degree  of  complexity  in  its  post- 
Glacial  deposits,  the  great  series  of  Glacial  lakes  on  itfj  eastern  side  being 
just  within  the  limits  of  the  State,  and  the  division  of  the  valley  into  two 
portions  by  the  sandstone  and  trap  ranges  from  Mount  Tom  southward 
being  wholly  confined  within  the  same  limits.  So  that  the  area  has  given 
me  a  section  of  sufficient  length  for  my  purpose  in  those  rocks  which  are  of 
great  extent  meridionally,  and  a  goodly  number  of  problems  of  which  all 
the  factors  are  within  its  limits. 

HISTORICAL  SKETCH. 

While  many  a  quaint  and  appreciative  remark  may  be  gathered  from 
the  records  of  the  explorers  and  early  settlers  of  the  Connecticut  Valley 
concerning  the  great  natural  beauty  of  the  new  country,  I  have  after  much 
search  found  nothing  which  had  reference  to  its  geological  structure. 
Considering  the  little  that  was  then  known,  even  among  the  learned,  con- 
cerning geology,  we  do  not  wonder  at  this.  It  is  more  a  matter  of  regret 
that  they  so  generally  failed  to  retain  the  Indian  names  of  the  prominent 
landmarks,  or  to  replace  them  by  significant  or  euphonious  svibstitutes. 
Except  the  name  of  the  Connecticut^  itself,  I  know  of  few  Indian  names 
retained  from  the  beginning  in  their  proper  application,  and  but  few  descrip- 
tive and  appropriate  names  which  have  come  down  to  us  from  the  fathers. 
Among  these  are  "The  Notch"  and  "The  Low  Place"  in  the  Holyoke 
range,  and  "Sugar  Loaf,"  named,  I  doubt  not,  by  the  Hadley  farmers  who 
rowed  over  to  mow  the  Hatfield  meadow,  whence  its  conical  shape  is  most 
striking  and  suggestive. 

It  is  true  that  in  late  times  the  names  Agawam  and  Chicopee  have 
been  applied  to  towns,  Mittineague  and  Willimansett  to  villages,  while  in 
a,  few  cases  the  Indian  names  of  brooks  seem  to  date  far  back,  as  Chicopee, 
Quinebaug,  Quabaug,  and  Scantic  rivers,  Pecowsick  and  Watchaug  brooks, 
and  Massasoit  Pond.  President  Hitchcock  attempted  to  baptize  several  of 
our  peaks  with  Indian  names;  i.  e.,  Nonatuck,  Norwottuck,  transferred  from 
the  Northampton  Meadows  to  the  peak  overlooking  them,  and  Metawampe, 
from  the  name  of  an  Indian  who  deeded  the  region  to  the  whites.     With 

'  Quiu  m  tuk=long-  tidal  river:  Coll.  Conn.  Hist.  Soc,  Vol.  II,  p.  8.  Quon  eli  ti  cut=tlie  long 
river:  Trumbull  Hist.  Coun.,  Vol.  I,  p.  32. 


HISTORICAL  SKETCH.  3 

these  exceptions  the  Indian  names  of  the  region  have  largely  passed  into 
the  possession  of  hotels  and  manufacturing  companies.  There  is,  on  the 
other  hand,  a  great  poverty  of  names  for  all  the  natural  features  of  the 
country,  "mount"  and  "hill,"  "brook"  and  "river,"  serving  rather  indis- 
criminately for  all  elevations  and  streams.  One  longs  for  the  rich  vocabu- 
lary of  Spain  and  Scotland.  Again,  the  names  given  are  often  trivial  and 
constantly  repeated.  All  the  larger  streams  have  an  east,  west,  and  middle 
branch,  and  I  remember  hearing  one  brook  called  the  "West  Branch  of  the 
Middle  Branch  of  the  Westfield  River."  There  are  several  "Swift"  rivers, 
"Roaring"  brooks,  "Muddy"  brooks,  and  eleven  "Mill"  rivers  (and  brooks) 
within  the  limits  of  the  three  counties. 

The  early  settlers  had  little  appreciation  of  the  natural  beauties  of  the 
landscape,  or  they  would  not  have  offended  the  poetical  ear  of  President 
Hitchcock  by  naming  our  finest  peaks  Mount  Toby  and  Bull  Hill,  and 
have  left  so  many  striking  objects  unnamed  entirely.  Certain  peculiarities 
of  nomenclature  have  grown  up  in  the  valley,  as  the  naming  of  mountain 
gorges  "gutters"  (e.  g..  Running  Gutter  in  Hatfield  and  Rattlesnake  Gutter 
in  Leverett),  of  alluvial  bottoms  "meadows"  (Hadley  Meadows),  and  of 
deep  narrow  valleys  "gulfs"  (Gulf  road  in  Northfield). 

In  1810  Prof  Benjamin  Silhman,  of  Yale  College,  visited  the  lead  mine 
in  Southampton  at  the  request  of  the  proprietors  and  drew  up  a  report  for 
their  use.  This  does  not  seem  to  have  been  printed  by  them  separately, 
but  was  published  by  the  author  the  same  year  in  the  second  number  of 
Brace's  Mineralogical  Journal,  in  which  also  a  paper  descriptive  of  some  of 
the  minerals  found  at  the  mine  was  published,  from  the  pen  of  Dr.  William 
Meade. 

The  pubHcation  of  Cleaveland's  Mineralogy  (1816)  and  of  the  first 
volume  of  Silliman's  Journal  (1818),  and  the  influence  of  Amos  Eaton  in 
Albany,  mark  the  beginning  of  a  strong  movement  toward  the  study  of 
mineralogy  and  geology  in  New  England.  The  first  articles  of  Edward 
Hitchcock  1  appear  in  these  years,  one  of  them,  "with  a  sketch  by  Mrs. 
Hitchcock,"  marking  the  beginning  of  a  scientific  partnership  which  was  to 
last  so  long,  and  which  has  made  this  region  classic  ground  for  the  geologist. 
From  this  time  on  for  a  half  century  nearly  all  that  became  known  con- 

'  Obituary:  Proc.  Am.  Acad.  Arts  Sci.,  Boston,  Vol.VI,  p.  291;  Hist.  Conn.  Valley,  1879,  Vol.  II 
p.  617.  ' 


4  GEOLOGY  OP  OLD  HAMPSHIEE  COUNTY,  MASS. 

cerning  the  geology  of  the  Connecticut  Valley  was  discovered  by  him,  and 
the  whole  body  of  knowledge  on  the  subject  was  systematized  in  his  suc- 
cessive reports.  So  frequent  mention  will  be  made  of  his  work  in  the 
following  pages,  and  its  progress  may  be  followed  so  fully  in  the  Chrono- 
logical List,  in  Chapter  XXIII,  that  special  mention  may  be  omitted  here 
and  attention  called  to  the  many  physicians,  teachers,  and  laymen  who 
became  enthusiastic  mineralogists  and  scoured  the  hills  so  thoroughly  that 
it  is  now  exceedingly  rare  that  one  finds  a  new  locality  for  minerals  within 
these  bounds.  Prominent  among  these  was  Dr.  David  Hunt,  of  Northamp- 
ton, to  whom  President  Hitchcock  acknowledges  great  obligation  for 
assistance  in  mineralogy  as  early  as  1818,  and  of  whom  Amos  Eaton  said 
that  he  had  every  mineral  in  this  part  of  the  State  at  his  call.^ 

Dr.  Jacob  Porter,  of  Cummington;  Emerson  Davis,  principal  of  the 
Academy  of  Westfield;  Dr.  William  Atwater,  of  Westfield;  Simeon  Colton, 
of  Monson,  and  Dr.  Ebenezer  Emmons,^  of  Chester,  who  commenced  his 
scientific  work  here,  were  among  the  professional  men  who  pursued  min- 
eralogy with  great  energy,  and  the  last  of  this  band  of  men,  Mr.  W.  Morris 
Dwight,  died  in  extreme  old  age  in  Williamsburg  only  a  few  years  ago. 

Prof  Amos  Eaton,  Dr.  George  Gibbs,  Prof.  Chester  Dewey,  and  Prof 
J.  T.  Webster  extended  their  studies  over  this  region  from  without,  so  that 
already  in  1825  Mr.  A.  0.  Hubbard,  writing  from  Yale  in  commendation  of 
Mr.  Hitchcock's  "excellent  description  of  the  Connecticut  Valley,"  says  the 
region  "is  becoming,  or  rather  has  already  become,  the  rallying  point  of 
all  the  mineralogists  in  Massachusetts." 

There  appeared  in  Silliman's  Journal  for  1827  an  article  on  the  lead 
mines  and  veins  of  Hampshire  County  by  Mr.  Alanson  Nash.  Prof.  C.  U. 
Shepard  was  then  assisting  in  the  publication  of  this  journal,  and  he  once 
described  to  me  the  difficulty  he  had  in  deciphering  the  crabbed  script  of 
the  author  and  in  bending  his  sentences  to  the  common  rules  of  grammar. 
Little  knowledge  of  the  distribution  of  the  lead  veins  has  been  added, 
however,  to  what  is  contained  in  that  article,  and  several  of  the  veins 
described  by  him  I  have  not  been  able  to  find,  though  I  do  not  doubt  their 
existence.  He  was  the  forerunner  of  a  great  body  of  natural  prospectors — 
men  without  learning,  books,  or  assistance,  who,  from  a  strong  love  of  the 

I  Index,  1820. 

=  Sketch  of  life,  by  J.  B.  Perry:  Proc.  Boston  Soc.  Nat.  Hist.,  Vol.  XII,  p.  214;  also  by  Jules 
Marcou:  Am.  Geologist,  Vol.  VII,  p.  1,  with  fine  portrait. 


HISTORICAL  SKETCH.  5 

quest,  roamed  over  the  hills  hunting  for  minerals,  and  became  as  acute  and 
skillful  in  the  search  as  theii'  neighbors  did  in  hunting  and  fishing.  I  do 
not  know  that  Mr.  Nash  was  a  cobbler,  but  I  suspect  so,  for  I  have  found 
both  here  and  in  Europe  that,  perhaps  from  the  intermittent  character  of 
their  employment,  men  of  this  trade  are  exceptionally  apt  to  develop  the 
taste  for  collecting  minerals. 

Of  the  long  list  of  these  men  who  have  forwarded  mineralogy  in  an 
unambitious  way  I  will  mention  only  Mr.  B.  Hosford,  of  Springfield,  who, 
at  the  suggestion  of  Professor  Shepard,  first  dissected  one  of  the  Lancaster 
chiastolites,  which  was  figured  in  Dana's  Mineralogy,  and  whose  study  of 
the  salt  crystals  in  Westfield  I  have  reported  in  Bulletin  No.  126  of  the 
United  States  Geological  Survey,  and  Mr.  William  Newell,  of  Pelham,  long 
time  cobbler  in  Amherst.  Students  long  before  and  after  my  time  in  college 
will  remember  his  love  of  minerals  and  his  reticence  concerning  his  "  locali- 
ties." There  was  a  pint  of  fine  amethysts  in  the  collection  at  Amherst  which 
he  had  gathered  from  the  gravels  of  Amethyst  Brook.  If  they  had  been 
solid  gold  they  would  have  poorly  paid  him  for  the  time  spent  in  searching 
for  them ;  being  amethysts,  however,  they  satisfied  him  much  better. 

The  first  mineral  from  Hampshire  County  to  receive  notice  abroad 
was  the  albite  of  Chesterfield  (cleavelandite),  which,  as  kieselspath,  was 
described  by  Ilausmann  in  1817.  The  first  article  on  minerals  from  this 
area  by  Professor  Shepard  appeared  in  1824,  beginning  a  half  century  of 
work  as  profitable  for  the  advance  of  mineralogy  in  this  region  as  that  of 
President  Hitchcock  was  for  the  progress  of  geology. 

The  halting  places  in  the  history  of  the  geology  of  the  valley  are  the 
dates  of  the  publication  of  the  principal  works  of  President  Hitchcock,  as 
follows : 

1818.  Remarks  on  Geology  of  a  Section  of  Massachusetts.  This  was 
followed  by  a  period  of  collecting  minerals  and  recording  their  localities, 
and  by  the  beginnings  of  geological  work,  especially  by  Prof.  Amos  Eaton. 

1823.  Sketch  of  Geology  of  the  Region  of  the  River  Connecticut. 
This  was  succeeded  by  a  continuation  of  the  collecting  and  recording  period. 

1833.  Report  on  Geology  of  Massachusetts. 

1835.  Report  on  Geology  of  Massachusetts,  second  edition.  This  was 
followed  by  the  most  interesting  episode  in  the  history  of  the  geology  of 
the  Connecticut,  the  discovery  and  description  of  the  very  numerous  and 


6  GEOLOGY  OF  OLD  HAMPSHIRE  GOUETT,  MASS. 

perfect  Triassic  tracks  found  up  and  down  the  valley,  with  which  discovery 
the  names  of  Dexter  Marsh/  Dr.  James  Deane,^  and  Dr.  Roswell  FiekP 
were  also  connected.  Previous  to  the  year  1884  I  was  for  a  long  time 
accustomed  to  arrang-e  the  successive  senior  classes  of  Amherst  College  on 
the  lawn  before  the  house  of  Dr.  Field,  in  Gill,  and  the  old  man  would 
come  out  and  give  the  boys  a  lecture  on  the  "true  theory  of  bird  tracks," 
claiming,  and  I  think  with  justice,  that  he  first  discovered  the  quadrupedal 
character  of  the  animals  which  made  the  tracks. 

1841.  Final  Report  upon  the  Greology  of  the  State.  This  summarized 
the  geology  of  the  region  to  date,  adding,  however,  very  little  to  the  report 
of  1835,  while  the  discussion  of  the  "bird  tracks"  went  on  vigorously  until, 
in  1844,  the  Report  on  Ichnology  brought  together  all  that  was  known 
on  the  subject,  with  abundant  illustrations — indeed,  vastly  increased  what 
was  before  known,  though  it  did  not  close  the  subject,  since  articles 
descriptive  and  controversial  continued  to  flow  from  the  pens  of  all  those 
mentioned  above,  as  well  as  more  elaborate  works  from  the  two  sons 
of  President  Hitchcock,  while  the  last  scientific  article  published  by  the 
President  himself  (1863)  was  concerning  New  Facts  and  Conclusions 
Respecting  the  Fossil  Footmarks  in  the  Connecticut  River  Valley. 

1860.  Illustrations  of  Surface  Geology.  With  this,  one  of  the  pioneer 
works  in  a  field  which  has  since  become  most  popular,  the  great  work  of 
President  Hitchcock  on  the  geology  of  the  Connecticut  closed. 

1863.  Reminiscences  of  Amherst  College.  This  book  contains  an 
aftermath  of  opinion  on  the  geology  near  Amherst. 

I  may  here  mention,  in  conclusion,  several  persons  who  have  advanced 
the  science  of  mineralogy  in  the  region,  or  at  least  have  gathered  valuable 
collections  for  the  use  of  other.  Mr.  James  T.  Ames,  proprietor  of  the 
well-known  foundries  at  Chicopee,  was  led,  perhaps  from  his  connection 
with  the  Chester  emery  bed,  to  gather  a  collection  very  valuable  for  the 
illustration  of  the  local  mineralogy ;  and  Dr.  H.  T.  Lucas,*  who  had  a  large 
share  in  the  discovery  of  the  emery  at  Chester,  has  been  identified  with 
the  exploitation  of  this  and  many  other  mining  properties  in  Hampshire 
County  for  many  years.  Mr.  M.  A.  Brown,  formerly  of  Northfield,  has 
done  very  useful  work  in  exploring  the  mineralogy  of  eastern  Franklin 

'For  sketch  of  his  life  see  History  of  the  Connecticut  Valley,  Vol.  II,  p.  585. 
2Ibia.,p.  520.  'Ibid.,  p.  576. 

^Ibid.,  Vol.  I,  p.  1064. 


HISTORICAL  SKETCH.  7 

County.  ^Ii".  (-)liver  M.  Clapp,'  of  Amherst,  recently  deceased,  was  an 
ardent  collector  during  his  long  life.  The  finest  collection  for  the  illus- 
tration of  the  local  mineralogy,  excepting,  of  course,  the  great  collection 
of  Professor  Shepard,  was  that  made  by  Mr.  Josiah  D.  Clark,  for  a  long 
time  a  teacher  in  Brooklyn,  but  a  native  of  Northampton,  who  watched 
carefully  the  progress  of  the  work  at  the  last  opening  of  the  Loudville 
mine,  during  the  war,  and  secured  very  abundant  and  wholly  unique 
suites  of  all  the  rare  things  found  there,  as  well  as  valuable  material  from 
all  other  localities  of  western  Massachusetts.  He  sold  his  collection  at 
an  exceptionally  low  price  to  Smith  College,  from  a  desire  that  it  might 
remain  entire  and  in  Northampton. 

The  burning  of  the  great  Shepard  mineral  collection  in  Walker  Hall  of 
Amherst  College  in  1882  may  stand  as  a  next  and  sad  epoch  in  the  history 
of  mineralogy  in  the  Connecticut  Valley,  a  loss  in  many  ways  irreparable, 
for  the  rich  store  of  material  for  the  illustration  of  the  local  mineralogy  can 
never  be  wholly  replaced.  Fortunately  Professor  Shepard  had  published 
largely  concerning  this  material,  and  I  had  taken  quite  full  notes  of  almost 
all  the  collection,  which  have  been  incorporated  in  the  following  report. 

In  December,  1887,  the  collections  made  by  Professor  Shepard  after 
the  sale  of  his  collection  to  Amherst  College  were  presented  in  his  name 
to  the  college  by  his  son.  Dr.  C.  U.  Shepard,  of  Charleston,  South  Carolina, 
and  this  goes  far  toward  restoring  the  monument  to  his  memory,  and  very 
far  toward  filling  out  the  local  collections  at  Amherst,  which  should  be,  of 
coiu'se,  unsurpassed  for  the  region  in  the  center  of  which  the  college  is 
situated. 

It  is  proper  to  call  attention  to  the  fact  that  the  list  of  publications 
upon  the  geology  and  mineralogy  of  the  State  (Chapter  XXIII),  in  which 
I  have  included  those  upon  topography,  is  the  true  history  of  the  progress 
of  these  studies  here  during  the  present  century,  and  that  in  the  preceding 
pages  I  have  purposed  only  to  emphasize  some  names  that  would  otherwise 
be  overlooked,  and  to  indicate  some  salient  points  in  the  history  which  seemed 
to  me  to  deserve  mention. 

'Hist.  Conn.  Valley,  Vol.  I,  p.  241. 


CHAPTER   II. 

TOPOGRAPHY. 

The  great  central  plateau  of  Worcester  County,  averaging  about  1,000 
feet  above  the  sea,  lowers  a  httle  toward  the  west,  and  is  accented  as  it 
passes  into  the  area  under  consideration  by  deep  north-south  longitudinal 
valleys,  the  streams  here  taking  for  long  distances  a  north-south  course,  and 
it  is  cut  deeply  by  two  great  transverse  valleys — those  of  the  Millers  and 
Chicopee  rivers — which  gather  all  the  drainage  from  the  east.  With  this 
modification  the  plateau  is  continued  westward  until  its  border  forms  the 
eastern  edge  of  the  Connecticut  Valley. 

'  The  rim  of  the  valley  on  its  west  side  is  the  border  of  a  similar  broken 
plateau  of  about  the  same  height,  deeply  cut  by  longitudinal  valleys  whose 
waters  also  reach  the  Connecticut  by  two  transverse  valleys — those  of  the 
Deerfield  and  Westfield  (or  Agawam)  rivers — which  are  farther  south  than 
the  corresponding  valleys  on  the  east,  each  by  about  the  same  distance. 
The  plateau  rises  along  the  western  portion  of  the  three  counties  into  the 
Berkshire  Hills.  It  will  be  noted  that  the  Connecticut  Valley  includes 
about  all  of  the  broad,  low  area  underlain  by  Triassic  rocks. 

These  two  plateaus  were  probably  once  parts  of  a  continuous  plain 
that  extended  across  the  Connecticut  and  other  valleys  far  beyond  the 
limits  of  the  area  studied.  This  plain  was  formed  by  erosive  agencies 
which  degraded  the  rocks  nearly  to  sea  level.  It  seems  to  have  been  well 
established  by  Professor  Davis  that  this  degradation  took  place  during  the 
Cretaceous  period,  and  that  a  later  Tertiary  elevation  enabled  the  streams 
to  cut  down  their  valleys  and  clean  out  the  wide  lowlands  in  the  soft  rocks 
that  border  the  Connecticut  and  the  eastern  branches  of  the  Swift  River  in 
Enfield.  The  peaks  and  ridges  of  more  resistant  rock  that  rise  in  these  low- 
lands still  reach  almost  to  the  level  of  the  old  plains,  and  are  remnants  of  it. 

8 


TOPOGRArHY.  9 

Of  the  longitudinal  valleys  the  most  i)eculiar  is  the  l)asiu  in  Greenwich 
and  Enfield,  in  the  eastern  portion  of  the  region,  in  which  the  branches  of 
the  Swift  River  join  and  move  southward.  It  is  a  broad,  low,  sand  plain, 
studded  with  isolated,  high,  rocky  islands  and  stretching  from  north  to 
south  through  these  towns.  The  streams  enter  and  leave  it  by  narrow 
channels,  while  the  plain  continues  south  through  Ware,  and  was  once,  I 
susjiect,  continuous  with  the  deep,  straight  valley  which  extends  through 
the  middle  of  Monson  and  on  into  the  valley  of  the  Willimantic;  and  it 
was  in  its  middle  part  (in  Palmer)  clogged  up  with  till  during  the  Grlacial 
period,  so  that  the  Swift  River,  which  on  this  supposition  formerly  ran 
southward  across  Palmer  and  Monson  into  the  Housatonic,  has  in  post- 
Glacial  time  found  its  way  westward,  breaking  through  the  side  of  the 
basin  to  join  the  Connecticut.  If  this  be  so  it  explains  at  once  why  the 
basin  is  so  disproportionate  to  the  size  of  the  present  river,  and  why  it  is 
on  all  sides  walled  in  by  high  ground,  except  the  narrow  gorge  by  which 
the  Swift  River  escapes  from  it.  It  also  explains  the  very  straight  Monson 
Valley,  in  the  middle  of  which,  just  at  the  State  line,  the  waters  run  south 
to  the  Willimantic  and  north  to  the  Quabaug  at  Palmer. 

The  Connecticut  Valley  stretches  across  the  center  of  the  area  from 
north  to  south,  with  a  width  of  about  IjV  miles  at  the  north,  which  increases 
to  8  J  miles  opposite  Greenfield,  10|  miles  opposite  Amherst,  and  averages 
15  miles  in  the  southern  portion  of  the  State.  It  is  divided  lengthwise  into 
two  portions  of  about  equal  width  by  the  remnants  of  the  red  sandstone 
and  the  long  trap  ridges  of  Deerfield  Mountain  and  the  Holyoke  range; 
and,  except  the  short  canyons  of  the  two  western  tributaries,  the  only 
breaks  in  this  dividing  wall  are  at  its  north  end  in  Bernardston  and  in  the 
long  distance  opposite  Amherst,  between  Sugar  Loaf  and  Mount  Holyoke. 
Post-Glacial  deposits  occupy  the  full  width  of  the  Connecticut  Valley  in 
great  complexity  and  beauty. 

From  the  northern  line  of  the  State  the  eastern  border  of  the  valley, 
sloping  rapidly  to  the  bottom,  runs  nearly  due  south  across  the  State, 
notched  sharply  by  the  gorges  of  the  Millers  and  Chicopee  rivers,  and 
rarely  opening  out  into  a  rounded  high-lying  valley,  as  in  Pelham,  opposite 
Amherst,  or  breaking  down  into  an  elevated  plateau,  as  in  Belchertown. 

On  the  west  the  high  gi-ound  crosses  the  State  line  but  a  little  way  back 
from  the  river,  and  for  a  few  miles  the  valley  preserves  the  same  narrow  limits 


10        GEOLOGY  OF  OLD  HAMPSHIEB  COUNTY,  MASS. 

and  simple  cliaracter  which  mark  its  more  northern  course.  The  crystal- 
hne  rocks  are  then  set  back  7  miles  to  the  west,  along-  the  northern  border 
of  Greenfield,  and  the  rocky  boundary  thence  goes  south,  with  sharp  east- 
ward slope,  notched  only  by  the  Deerfield  gorge,  to  be  again  set  back  by 
about  the  same  amount  along  the  north  of  Northampton.  It  then  runs 
south  again,  interrupted  only  by  the  Westfield  River,  to  and  beyond  the 
south  line  of  the  State. 

On  both  sides  the  brooks  and  the  roads  (which  usually  follow  the 
brooks)  come  down  sharply  from  the  uplands,  and  railroads  can  enter  and 
leave  the  valley  only  by  the  four  tributaries  mentioned  above. 

Just  south  of  where  the  western  boundary  first  turns  westward,  in 
Greenfield,  a  great  block  of  red  sandstone  hills,  occupying  the  whole  town 
of  Gill,  separates  the  valley  into  two  parts,  the  river  occupying  the  eastern 
portion  and  the  narrow,  high  Bernardston  Pass  connecting  it  with  the  north 
end  of  the  western  portion.  From  the  southwest  corner  of  this  mass  the 
Deerfield  trap  sheet  runs  southward,  forming  Deerfield  Mountain,  its  ver- 
tical western  scarp  making  the  eastern  boundary  of  the  western  lateral 
valley,  which  preserves  its  width  southwardly  through  Deei-field,  while  east 
of  it  the  valley  of  the  Connecticut  proper  expands  into  the  Montague  basin, 
the  ridge  being  much  narrower  than  the  block  of  hills  in  Gill,  which  makes 
the  northern  border  of  this  basin.  On  the  south  the  great  mass  of  Mount 
Toby  shuts  in  this  Montague  basin,  the  river  passing  in  a  narrow  valley 
between  it  and  the  south  end  of  the  Deerfield  range,  which  ends  abruptly 
with  Sugar  Loaf,  into  the  much  broader  Hadley  basin,  while  a  deep,  nar- 
row valley  around  the  east  side  of  Mount  Toby  also  connects  the  two. 
By  the  breaking  down  of  the  Deerfield  range  the  Deerfield  Valley  opens 
widely  into  the  broad  Hadley  basin,  which  here  has  the  full  width  of  the 
Connecticut  Valley,  1 4  miles,  between  the  crystalline  borders  on  the  east 
and  west,  though  Mount  "Warner,  a  mass  of  crystalline  rocks,  stands  mid- 
way to  partly  continue  the  ba,rrier. 

South  of  Amherst  the  Holyoke  range  rises  abruptly  athwart  the  valley, 
lea,ving  a  narrow  passage  on  the  east  into  the  Springfield  basin,  like  that 
around  the  east  end  of  Mount  Toby,  while  it  is  broken  through  for  the 
escape  of  the  river  just  as  the  latter  comes  through  a  narrow  passage 
between  Mount  Toby  and  Sugar  Loaf  on  its  entrance  to  the  basin. 

The  Holyoke  range  extends  south  along  the  western  border  of  the 


TOPOGRAPHY.  H 

Sprin<>-field  basin,  \vliilo  its  steep  western  slope  is  the  eastern  boundary  of  a 
lateral  valley,  similar  in  size  and  position  to  the  Deerfield  Valley,  of  which, 
indeed,  it  may  be  looked  upon  as  the  continuation,  and  this  valley  extends 
across  Southampton  and  Southwick  and,  as  the  Farmington  Valley,  is  con- 
tinuous to  the  Sound. 

The  Springfield  basin  is  also  continued  beyond  the  limits  of  the  State, 
and,  though  contracted  at  the  Enfield  Falls,  is  not  terminated  until  it  reaches 
the  narrows  at  Middletown,  Connecticut. 

On  the  east  the  longitudinal  valleys,  especially  the  Enfield  Valley,  are 
largely  due  to  the  folding  of  bands  of  newer  and  harder  schists  down  into 
the  gneiss  and  the  subsequent  deeper  erosion  of  the  latter.  On  the  west, 
where  the  whole  area  is  occupied  by  closely  folded  schists,  one  can  only 
rarely  see  any  connection  between  the  valleys  and  the  dm-ability  of  the 
bottom  rocks. 

The  topography  of  the  northwest  portion  of  Franklin  County  is,  how- 
ever, very  plainly  influenced  by  its  stratigraphy.  The  Deerfield  River,  on 
entering  the  State,  runs  southward  with  the  strike  of  the  Hoosac  schist.  It 
then  bends  and  ciits  across  this  strike  at  right  angles,  and  then  turns  south- 
west again  with  the  strike,  and  repeats  this  zigzag  several  times,  and  at 
last,  reaching  the  great  fault  at  the  portal,  it  turns  sharply  east  across  the 
sericite-schists.  All  the  orographic  lines  in  Rowe — the  mountain  ridges  and 
the  intervening  valleys — are  for  the  same  reason  directed  southwest,  par- 
allel to  the  abnormal  strike  of  the  rocks  thereabout.  The  deep  depression 
in  which  Shelburne  Falls  lies  is  plainly  the  result  of  the  great  quaquaversal 
by  which  the  gneiss  is  here  exposed,  and  is  the  expression  of  its  lesser 
durability. 

Across  the  western  half  of  Hampshire  and  Hampden  counties  the 
drainage  is  southeast,  and  is  only  in  a  minor  degree  controlled  by  the  north- 
south  structure  of  the  rocks.  The  east  branch  of  the  Westfield  River  flows 
from  Cummington  south  to  its  mouth  with  the  strike,  curving  around  the 
Groshen  anticlme,  and  its  gorge  above  West  Chesterfield  Hollow  and  the 
gorge  of  the  Westfield  Little  River  are  the  wildest  in  the  State. 


CHAPTER  III. 

GEOLOGICAL   OUTLINE   AND   GENERAL    COMPARATIVE 

SECTIONS. 

A  long  series  of  Archean  outcrops  runs  from  north  to  south  across  the 
western  portion  of  the  high  ground  between  the  Housatonic  and  the  Con- 
necticut valleys,  and  barely  enters  the  western  border  of  the  area  here 
described.  This  high  ground  is  the  continuation  of  the  Green  Mountain 
range  across  Massachusetts.  Cambrian  conglomerate-gneisses  (Becket 
gneiss)  wrap  around  these  patches  of  Archean,  gi-aduate  westward  into  the 
Stockbridge  limestone,  and  dip  eastward  beneath  the  great  sericite-schist 
series,  which  may  be  placed  parallel  to  the  Berkshire  and  Greylock  schists 
on  the  west.  These  highly  metamorphosed  and  much  foliated  sericite- 
schists  stand  vertical  in  appressed  folds  for  a  long  distance  eastward  and 
then  go  beneath  the  extensive  graphitic  schist  series,  coming  up  farther  east 
in  anticlines  from  beneath  the  latter.  A  remarkable  band  of  amphibolites, 
with  enstatite-bearing  limestones  and  enstatite,  pyroxene,  and  olivine  rocks, 
all  largely  changed  to  serpentine,  and  with  emery,  runs  down  the  middle 
of  the  sericite-schists.  It  seems  to  me  possibly  the  equivalent  of  the  Bel- 
lowspipe  limestone  of  Greylock ;  and  the  Bolton  limestone,  farther  east,  is 
upon  about  the  same  horizon.  The  upper  series  of  graphitic  schists  (the 
Goshen  and  the  Conway  schists)  is  less  metamorphosed,  and  shows  much 
of  the  original  lamination,  though  masked  by  cleavage  and  foliation.  It 
contains  many  beds  of  limestone  in  every  stage  of  change  to  amphibolite. 
It  is  a  graphitic  muscovite-schist,  abounding  in  garnet,  staurolite,  and 
transverse  spangles  of  biotite.  It  graduates  into  the  corrugated  and 
cleaved  Leyden  argillite  (phyllite)  along  the  eastern  border  of  the  elevated 

12 


GEOLOGICAL  OUTLINE,  13 

area  defined,  above,  and  upon  it  rests,  at  the  lower  level  of  the  Connecticut 
Valley,  the  complex  Bernardston  series — conglomerates,  quartzites,  lime- 
stone, mica-  and  hornblende-schists,  and  gneiss — which  is  proved  by  the 
presence  of  many  fossils  to  belong  in  the  Upper  Devonian. 

A  complex  series  of  faults,  with  much  westward  overthrusting,  bounds 
the  elevated  area  on  the  west.  A  series  of  echeloned  faults  also  di-ops  the 
bottom  rocks  of  the  Connecticut  Valley  on  the  east  and  makes  the  elevated 
area  a  "horst"  and  the  valley  bottoms  "graben,"  in  the  nomenclature  of 
Suess.^ 

A  great  stock  of  tonalite,  or  quartz-diorite,  occupies  the  eastern  border 
of  the  area  and  encroaches  on  the  Connecticut  Valley.  This  has  come  up 
through  the  thick  Whately  amphibolite  bed.  It  graduates  westwardly  into 
the  gi'anitite,  or  biotite-granite.  This  has  emerged  in  the  region  of  the 
broad  Whately  limestone  bed.  This  is  followed  outwardly  by  a  great 
group  of  dikes,  of  every  size,  of  granite  or  muscovite-biotite-granite.  This 
is  in  the  region  of  the  muscovite-schists  without  limestone.  Each  of  these 
rocks  seems  thus  to  be  distinctly  influenced  in  its  chemical  constitution  by 
the  rocks  it  has  penetrated  and  dissolved.  On  the  periphery  are  great 
quartz  veins,  and  the  remarkable  tourmaline-  and  cleavelandite-bearing 
dikes,  with  minerals  containing  rare  elements. 

Farther  west  all  the  sericite-schists  and  Cambrian  gneisses  are  free 
from  later  igneous  rocks  except  the  great  isolated  granitite  dike  in 
Middlefield. 

The  valley  of  the  Connecticut  may  in  a  general  way  be  called  a  broad 
syncline,  so  far  as  the  crystalline  rocks  are  concerned.  It  is  rather  a 
broad  area  of  greater  crushing  and  disturbance,  which  has  favored  greater 
erosion,  and  over  its  bottom  the  crystalline  rocks  lie  often  horizontal  or 
in  small  anticlines  and  synclines,  while  on  its  borders  they  dip  toward 
the  center,  often  with  high  angles.  In  attempting  to  trace  the  history 
of  the  valley,  it  will  perhaps  always  be  impossible  to  assign  their  proper 
weight  to  the  erosive  agencies  mentioned  above  in  comparison  with 
another  agency  which  has  been  of  prime  importance  in  the  formation 
of  the  valley.  I  mean  that  which  has  produced  the  great  faults  and 
the    sinking  of  the  areas  between  the  faults.     The  principal  southwest- 

1  E.  Sueas,  Das  Antlitz  der  Erde,  Vol.  I,  pp.  166,264. 


14        GEOLOGY  OF  OLD  HAMPSHIEB  COUNTY,  MASS. 

by-soutli  fault,  which  appears  so  plainly  on  the  map,  forming  the  eastern 
bonndary  of  the  valley  across  Northfield  and  Montague,  is  probably  pro- 
longed in  the  Holyoke  range  fissure  from  Mount  Tom  southward.  From 
a  point  north  of  Mount  Toby  a  fault  branches  from  the  main  one  and 
is  continued  down  the  east  side  of  the  valley,  a  series  of  great  faults 
running  south  by  east  at  the  eastei'n  border  of  the  valley;  and  much 
the  same  seems  true  of  the  western  side,  and  especially  the  two  settings- 
back  of  the  valley  border  seem  due  to  the  two  east-west  faults.  How. 
far  the  valley  bottom  has  been  depressed  between  these  faiilts  I  can  not 
determine,  but  the  great  thickness  of  the  red  sandstone,  as  shown  by 
artesian  wells,  would  indicate  that  the  sinking  must  have  been  consid- 
erable after,  and  perhaps  during  and  before,  the  deposition  of  the  Trias. 

The  region  is  thus  a  great  "graben" — a  band  of  country  sunk  between 
parallel  faults;  and  the  great  Grreenwich-Enfield  basin  has,  at  least  in  part, 
the  same  character,  though  here  erosion  has  been  the  more  important  agent, 
and  in  its  northward  extension  into  New  Salem  and  Orange  the  sole  agent. 

In  both  pre-Triassic  and  Triassic  time  the  Connecticut  Valley  has  been 
a  region  of  extensive  faulting  and  the  pre-Triassic  faulting  extends  con- 
siderably east  of  the  present  bottom  of  the  basin,  especially  in  the  Northfield 
region. 

All  the  rocks  of  the  area  west  of  the  Connecticut  reappear  in  the 
eastern  region.  The  Bernardston  rocks  are  present  only  in  a  few  outcrops 
in  Northfield  and  farther  south,  while  the  Leyden  argillite  appears  in  the 
south  bank  of  the  Connecticut  just  below  the  mouth  of  Millers  River,  and 
seems  to  run  down  the  valley  beneath  the  Trias  and  to  appear  west  of  the 
pond  in  the  center  of  Leverett.  It  is  also  represented  lithologically  in  the 
center  of  the  middle  syncline  in  Monson. 

The  salient  features  of  the  eastern  area  are — 

(:Z)  The  eruptive  rocks,  consisting  of  (a)  the  great  block  of  diallage- 
granite,  or  tonalite,  and  quartz-gabbro  in  Belchertown  and  the  surrounding 
towns,  around  which  the  crystalline  rocks  are  thrown  into  great  confusion; 
(&)  the  block  of  diorite  in  New  Salem  and  Prescott,  which  seems  to  have 
produced  very  little  confusion  in  the  surrounding  rocks;  (c)  The  Coy's  Hill 
porphyritic  granitite ;   (d)  the  large  granite  areas  in  Leverett  and  Amherst. 


GEOLOGICAL  OUTLINE.  15 

(:i)  The  Monson  rjneis.s. — The  great  plateau  of  Cambrian  gneiss  which, 
starting  in  Northfiehl,  runs  through  Wendell,  Shutesbury,  and  Pelham,  and 
ends  against  the  Belchertown  tonalite,  furnishes  the  key  to  the  structure 
of  the  region.  It  is  another  "horst" — a  great  area  of  ancient  crystalline 
rocks  bounded  by  faults  outside  which  the  ground  has  everywhere  sunk 
away.  It  is,  moreover,  a  region  of  very  gentle  dips,  unlike  the  western 
hill  countr)^  The  rocks,  horizontal  in  the  center,  dip  slightly  toward  the 
borders  on  the  east  and  west.  It  is  bounded  by  north-south  faults  on 
either  side,  which  extend  wholly  or  nearly  across  the  State.  These  faults 
are  lines  or  bands  of  extreme  crushing,  and  outside  them  the  rocks  have 
been  compressed  in  sharp  folds,  as  if  they  had  been  thrust  against  the 
vmyielding  shoulders  of  the  great  "horst."  The  normal  Monson  gneiss 
is,  however,  the  ordinary  biotite-gneiss.  One  of  the  faults  mentioned 
runs  at  the  foot  of  the  high  grounds  along  the  east  border  of  the  broad 
Connecticut  Valley,  from  Northfield  south,  through  the  notches  at  the 
east  foot  of  Mount  Toby  and  at  the  east  end  of  the  Holyoke  range,  and 
so  on  through  Granby  and  Wilbraham.  As  noticed  above,  this  fault 
forms  also  the  eastern  boundary  of  the  Connecticut  Valley  "graben."  The 
other  fault  runs  in  a  corresponding  position,  along  the  east  border  of  the 
valley  of  the  west  branch  of  the  Swift  River,  through  Wendell,  New 
Salem,  Prescott,  and  Enfield.  The  faults  are  marked  by  great  crush- 
ing of  the  rocks,  by  the  development  of  curious,  "fault  rocks" — bastard 
granites  and  green  and  buff  hornstones — and  by  the  cementation  of  the 
crushed  rocks  by  comby  vein  quartz  and  specular  iron.  Within  the  "horst" 
the  Monson  gneiss  contains  a  thick  bed  of  a  fine-grained  actinolite-quartzite 
or  at  times  fine  biotite-quartzite  or  biotite-gneiss. 

(5)  The  schists. — Outside  these  faults  the  upper  schists  are  present  in 
the  same  series  as  west  of  the  river,  ^^z:  (a)  A  feldspathic  mica-schist  or  two- 
mica-gneiss,  at  times  a  quartzite  or  quartz-conglomerate,  is  the  equivalent  of 
the  feldspathic  mica-schist  or  Hoosac  schists  and  the  lower  sericite-schist  or 
Rowe  schists  of  the  west  side.  This  is  named  after  the  more  persistent  and 
important  bed  of  the  western  area,  the  Rowe  schist.  (&)  A  hornblende- 
schist=:the  Chester  amphibolite.     (c)  A  micaceous  quartzite,  very  generally 


16        GEOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 

containing  a  hydrated  mica  or  a  greeu  chloritic  mineral,  which  is  at  times 
certainly  derived  from  garnet ;  or  the  series  is  developed  as  a  whetstone- 
schist — that  is,  as  a  thin-bedded,  finely  biotitic,  arenaceous  quartzite.  It  is 
the  upper  sericite-schist,  or  Savoy  schist,  (d)  A  mica-schist,  in  great  thick- 
ness at  times,  exactly  like  the  finely  corrugated  biotite-spangled  garnet- 
schist  of  Conway  and  Groshen,  as  in  Northfield  Mountain,  on  the  Shutesbury- 
New  Salem  line,  and  in  Monson.  Usually  it  is  a  coarse,  barren,  muscovite- 
biotite-schist,  like  most  of  the  Conway  schist,  but  always  without  limestone, 
which  seems  to  be  replaced  by  hornblende-schists.  It  is  the  equivalent  of 
the  Groshen  schist  and  the  Conway  schist.  It  is  named  after  the  more 
important  member  and  the  one  it  most  resembles — the  Conway  schist. 

Instead  of  appearing  in  broad  areas,  succeeding  each  other  from  west 
to  east^i.  e.,  from  below  up,  as  they  do  in  the  western  hills — the  schists 
appear  here  in  sharply  compressed  synclines  which  run  across  the  State, 
disjointed  by  faults  and  thrown  into  confusion  by  the  presence  of  eruptive 
rocks.  Four  such  great  synclines  can  be  traced  across  the  State,  within 
the  limits  of  the  three  river  counties,  though  their  identity  is  disguised 
by  the  fact  that  metamorphic  changes  superinduced  upon  original  variations 
in  composition  have  varied  greatly  both  in  kind  and  degree.  One  may 
especially  adduce  the  fibrolitization  which  has  progressively  affected  the 
mica-schist  from  west  to  east  and  from  north  to  south. 

For  the  reasons  given  above  it  will  be  more  convenient  to  follow  a 
geographical  rather  than  a  geological  order  in  the  discussion  of  the  eastern 
schists  and  to  take  up  the  diff"erent  synclines  in  succession. 

GENEEAL   COMPARATIVE   SECTION   OP   KOCKS   IN  MASSACHUSETTS. 

In  the  first  column  of  the  accompanying  general  section  I  have  placed 
the  section  for  northwestern  Massachusetts,  as  determined  by  the  labors  of 
Professors  Pumpelly,  Dale,  and  Wolff",  ^  though  they  must  not  be  held 
responsible  for  the  exact  parallelism  here  attempted.  The  distinction 
between  the  Becket  conglomerate-gneiss  below  and  the  Cheshire  quartzite 
can  not  here  be  always  maintained,  and  the  quartzite  graduates  both 
laterally  and  vertically  into  the  limestone. 

The  area  east  of  the  Connecticut  and  extending  slightly  into  Worcester 

'Geology  of  the  Green  Mountains  in  Massachusetts:  Men.  U.  S.  Geol.  Survey,  Vol.  XXIII,  1894. 


GEOLOGICAL  OUTLINE. 


17 


County  forms  a  strong  contrast  to  that  west  of  the  river,  and  is  an  area  of 
transition  to  the  much  simpler  structure  of  Worcester  County.  Meta- 
morphism  and  the  part  taken  by  post-Carboniferous  eruptives  increase 
reyuUirly  eastward.  Such  rocks  are  Avanting-  in  the  first  column  and  in 
tlie  western  half  of  the  country  covered  by  the  second.  In  the  eastern  half 
iif  the  latter  the  granites  begin  and  rapidly  become  important;  in  the  second 
other  rocks  are  associated,  and  in  the  area  of  the  last  column  they  cover 
more  than  half  the  surface.  In  a  column  devoted  to  the  Massachusetts 
coast  region  eruptive  rocks  would  be  still  more  predominant. 

General  section  showing  correlation  of  rocks  in  Massachusetts. 

[The  names  given  in  tlie  second  and  third  columns  are  those  used  in  this  monograph.    Those  in  the  foui-th  column  will  he 
used  in  a  forthcoming  memoir  on  the  geology  of  Worcester  County.] 


Taconio  Kange  and 
Houaatonic  Valley. 

Berkshire  Hills  and 
Connecticut  Valley. 

East  of  Connecticut 
River. 

"Worcester  County. 

Black   Eock   diabase 

Tlie    whole    Triassic 

(intruaive). 

series    is    repeated 

Chicopee  shale. 

east  of  the  river. 

Longmeadow    sand- 

stone. 

Granby  tuff. 

g 

Mount  Holyoke  dia- 
base (iuterbedded). 

Sugar  Loaf  arkose. 

Mount  Toby  conglom- 
erate. 

Unconformity. 

•  m  ^ 

Granite.    Granitite, 

G  r  a  nite.    Granitite. 

Granite.    Granitite. 

H% 

Pegmatite.  Albitic 

Pegmatite .    Albitic 

Pegmatite.  Albitic 

granite.    Tonalite. 

p;ranite.      Tonalite. 

granite.     Tonalite. 

g|.§ 

Diorite.    Diabase. 

Diabase.     Olivine- 

"^^^ 

Cortlandite. 

gabbro.    "Wehrlite. 

i 

"Worcester      argillite 

1 

(phyUite). 

1  ' 

u 

o 

Harvard    conglomer- 
ate. 
"Worcester  quartzite. 

EerDardston    mica- 

Bernardston    m  i  c  a  - 

scbist. 

schist. 

Bernardston  araphib- 

^ 

olite. 

g    . 

Bernardston    quartz- 

Bernardston    quartz- 

t- 

ite. 

ite. 

fi 

Bernardston     1  i  m  e  ■ 

stone. 
Vernon    gneiss. 

Vnconforinity. 

MON  XXIX- 


18  GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

General  section  showing  correlation  of  rocks  in  Massachusetts — Continued. 


Taconic    Kange    and 
Houaatonic  V  alley. 

Berkshire  Hills  and 
Connecticut  Valley. 

East  of  Connecticut 
Kiver. 

"Worcester  County. 

r 

Leyden  argillite. 

Leyden  argillite. 

Conway  dark  corru- 

Conway schist,  chang- 

Brimfield rusty  fibro- 

gated     mica-schist 

ing    eastwardly   to 

lite-schist. 

u 

■with  garnets. 

Brimfield   rusty  fi- 

Gosben  flaggy  biotitic 

brolite-schists. 

muscovi  le  -schist 

with  quartzite  and 

limestone  beds. 

I 

Unconformity. 

Haw  ley    actinolitic 

chlorite-schist, 

1, 

ampbibolite,  pyrite, 

and  hematite  beds. 

m 

Greylock  schist. 

Savoy  chloritic  seri- 
cite-schist. 

Savoy  schist. 

Bellowspipe     1  i  m  e  ■ 

Chester  ampbibolite, 

Chester  ampbibolite. 

Fasten    whetstone- 

q3 

stone. 

with  emery,  serpen- 

schist. 

o 

tine,  steatite,    and 
saxonite. 

(Changes  east  of  the 
Carboniferous  into 

Berkshire  schist. 

Kowe  quartzose  seri- 
cite-schist    with 
ampbibolite  beds. 

Kowe  flaggy  schist.  \ 

Bolton    gneiss,    in- 
cluding Boltonlime- 
8  tone.) 

Stockbridge     1  i  m  e  - 

Hoosac  albitic  sericite- 

stone. 

sebist. 

Stockbridge     1  i  m  e  - 

Cheshire  white  gran- 

Pelham quartzite. 

Grafton  quartzite  and 

i 

stone,  lower  part. 

ular  quartzite. 

conglomerate. 

"Vermont  formation 

Becket    white    con- 

Monson conglomerate- 

Sutton  gneiss. 

i 

(quartzite     and 

glomerate-gneiss. 

gneiss. 

u 

gneiss). 

Unconformity. 

Stamford  gneiss  (por- 
phyritic      gneiss 
with  blue  quartz) . 

"Wasbiugton   blue 

quartz-gneiss. 
Tyringbam  stretched 

Ifl'ortbbridge  gneiss. 

d 

biotite-gneiss. 

',3 

EastLee  black  biotite- 

1^ 

o 

hornblende- gneiss. 

< 

Hinsdale  coarse  chon- 
drodite-liniestone. 

Hinsdale  granitoid 
gneiss. 

CHAPTER   IV. 
THE  ALGONKIAN.i 

GEOIiOGICAI/  DESCRIPTION. 

THE    HINSDALE    AREA.^ 

Before  my  work  had  extended  to  the  western  border  of  the  region 
covered  by  this  study,  my  attention  was  called,  in  the  winter  of  1882,  by 
Prof.  J.  D.  Dana,  to  two  interesting  outcrops  of  undoubted  Archean  rocks 
in  Hinsdale,  a  gneiss  and  a  limestone  containing  chondrodite  and  a  ^Deculiar 
peach-blossom-colored  mica,  determined  by  him  to  be  probably  rhodo- 
clirome.  Although  these  localities  lie  beyond  the  western  border  of  the 
river  counties,  the  same  rock  extends  into  the  southwest  corner  of 
Middlefield,  and  Professor  Dana's  discovery  was  very  acceptable  to  me  as 
furnishing  a  possible  base  to  work  from  in  the  complex  region  under 
examination. 

The  two  localities  in  question  are  at  the  first  cutting  west  of  the 
railroad  station  in  Hinsdale  and  at  the  first  cutting  south  of  the  railroad 
station  in  Washington,  and  as  they  give  a  much  fuller  exhibition  of  the 
series  thaa  the  limited  portion  of  the  same  which  enters  Middlefield,  they 
are  made  ih  the  main  tlie  basis  of  the  description  following. 

The  greater  portion  of  the  town  of  Hinsdale  is  occupied  by  an  oval 
anticline,  elongated  north  and  south  and  overthrown  to  the  west.  This 
extends,  much  contracted,  across  "Washington,  and  bending  southeastward 
and  narrowing  still  more  it  enters  Middlefield  and  runs  along  the  south  line 
of  the  town  to  a  point  a  mile  beyond  Becket  station.  The  newer  gneisses, 
all  down  the  east  side  of  the  anticline,  dip  normally  eastward  away  from 
the  older,  but  here — that  is,  where  the  narrow  band  of  Algonkian  extends 
east  along  the  Westfield  River— a  sharp  east-west  wrinkle  forms  in  the  newer 
gneiss,  and  the  older  gneiss  buckles  up  through  the  newer. 

'Azoic  (Lyell),  Eozoic  (Dawson),  Archseau,  Dana. 

"  This  will  be  described  in  detail  in  a  monograph  on  the  Archean  of  Berkshire  County. 

19 


20        GEOLOGY  OP  OLD  HAMPSHIRE  COUNTY,  MASS. 

Counting  from  below  upward,  the  Algonkian  rocks  may  be  divided 
into  four  groups: 

1.  Hinsdale  gneiss. — This  is  a.  group  of  gray  biotite-gneisses,  generally 
quite  coarse  and  with  the  jet-black  biotite  in  distinct,  elongate  patches, 
granitoid  and  yet  well  foliated.  The  broad,  fresh  cleavage  surfaces  of  the 
feldspar  are  often  strongly  curved  from  pressure.  These  gneisses  weather 
with  exceptional  rapidity  and  seem  to  be  calcareous. 

2.  Hinsdale  limestone. — The  coarsely  crystalline  chondrodite-limestones 
form  a  concentric  band  around  the  older  gneisses,  marked  by  a  series  of 
abandoned  limekilns,  for  the  rock  was  economically  important  before  the 
opening  of  the  "Western  Railroad." 

3.  Lee  gneiss. — This  is  a  heavy  black  hornblende-  or  hornblende-biotite- 


gneiss. 


i.  Washington  gneiss. — A  broad  band  of  rusty  graphitic  blue-quartz 
gneiss  forms  the  outer  circle  of  this  Algonkian  nucleus.  It  is  in  the  main 
a  biotite-gneiss,  but  with  little  mica,  and  rusty  from  the  decomposition  of 
hornblende,  pyrite,  pyrrhotite,  and  a  ferruginous  dolomite.  In  the  whole 
circuit  graphite  is  a  never-failing  accessory,  especially  in  the  upper  por- 
tion. The  graphite  mine  at  Washington,  except  for  the  size  of  some  of  the 
constituents,  suggests  the  Ticonderoga  graphite  mines.  Very  coarse  calcite, 
graphite  in  broad,  thin,  hexagonal  plates,  coarse  white  sahlite,  large  green 
pyroxene  and  hornblende  masses,  groups  of  finely  terminated  pistachio- 
green  pyi-oxenes,  brown  sphene,  and  garnets,  followed  paragenetically  by 
coarse  calcite  with  phlogopite,  and  this  by  quartz,  are  some  of  the  points  of 
resemblance.  , 

Another  equally  persistent  and  characteristic  constituent  of  these 
gneisses  is  a  blue  quartz  in  flat  laminse  1  to  3"°™'  in  thickness,  which  has 
often  so  deep  a  tint  of  rich  purplish  blue  as  to  furnish  beautiful  cabinet 
specimens,  and  is  so  abundant  as  to  form  more  than  three-fourths  of  the 
mass  of  the  rock. 

Everywhere  in  the  outer  circuit  of  the  Algonkian  rocks  a  band  having 
the  above  peculiarities  lies  below  the  lowest  beds  of  the  Cambrian  con- 
glomerate-gneiss, viz,  blue  quartz  formed  in  place,  disseminated  graphite, 
beds  of  the  heavy  black  hornblende-gneiss,  and  a  general  abundance  of 
hornblende  and  a  very  general  rustiness,  all  associated  with  intervening 
bands  of  a  common  biotite-gneiss. 


THE  HINSDALE  AKEA.  21 

From  the  Washing-ton  station  the  older  gneiss  narrows  and  occupies 
the  sides  and  bottom  of  the  narrow  canyon,  which  continues  toward  Becket 
station.  The  canyon,  caused  by  the  projection  of  this  narrow  lobe  of  the 
older  rocks,  is  one  of  the  most  curious  and  interesting  topographic  features 
of  the  region.  The  lesser  capacity  of  resistance  to  erosion  of  the  older 
gneisses  and  limestones  has  caused  the  broad  depression  in  which  Hinsdale 
lies,  and  the  southward  projection  of  the  same  rocks  has  determined  the 
long,  nan-ow  canyon  in  which  the  waters  of  the  Westfield  River,  gathering 
in  Washington,  flow  southward,  thus  providing  the  only  chance  for  railway 
communication  between  the  Connecticut  and  Housatonic  valleys.  At 
Becket  station,  south  of  the  river,  everything  is  newer  gneiss.  Just  north, 
in  the  village,  appear  the  hornblende  beds  of  the  upper  Algonkian  band,  and 
following  the  road  north  to  the  pasture  overlooking  the  village,  one 
finds  abundant  outcrops  of  the  blue-quartz  gneiss  and  the  contact  on  the 
conglomerate-gneiss  striking  southeast  and  dipping  northeast — that  is,  in 
the  normal  relation  to  each  other.  This  allows  them — the  older  gneisses — 
to  appear  in  a  band  on  the  north  side  of  the  brook,  which  band  seems  to 
contract  and  come  to  its  apex  just  at  the  point  where  the  i-ailroad  enters 
Middlefield,  so  that  thence  southeastward  it  appears  to  be  wholly  wanting 
at  the  surface,  or  is  perhaps  only  concealed  in  the  bed  of  the  river.  It 
however  makes  its  presence  below  manifest  by  a  continuation  eastward  along 
the  river  of  the  overturned  anticline  without  the  core  of  exposed  Algonkian, 
until,  at  the  junction  of  Coles  Brook  with  the  river,  the  Algonkian  chon- 
drodite-limestone,  accompanied  by  heavy  dark  gneiss,  buckles  irregularly 
up  through  the  conglomerate-gneisses. 

THE   COLES   BROOK  ANTICLINE. 

Just  a  mile  northwest  of  Bancroft  station,  Middlefield,  the  Boston  and 
Albany  Railroad  cuts  off  a  loop  of  the  Westfield  River,  and  Coles  Brook 
enters  this  loop.  The  railroad  runs  in  a  deep  cut  a  long  distance  before 
reaching  this  loop,  and  the  cut  continues  through  the  loop  and  most  of  the 
way  to  the  station.  At  bridge  143  the  Cambrian  white  or  conglomerate 
gneiss  in  synclinal  posture  mounts  up  on  the  older  gneiss,  which  I  have 
called  the  East  Lee  or  black  gneiss  from  its  large  development  just  above 
the  limestone  in  the  Lee-Tyringham  region.  It  is  especially  contorted 
and  cut  by  pegmatite  at  the  junction,  and  consists  of  a  great  thickness  of  a 


22 


GEOLOGY  OP  OLD  HAMPSHIRE  COUNTY,  MASS. 


wavy-bedded  gneiss  of  fine  grain  and  almost  black  from  the  abundance  of 
the  black  biotite.  (See  fig.  1.)  Contorted  white  veins  one-fourth  inch  to  2 
inches  wide  run  through  the  rock,  high  up  in  the  cutting, 
with  most  tortuous  course,  and  on  the  south  side  I  could 
recognize  the  spot  whence  came  a  great  block  which  has 
long  lain  in  front  of  the  geological  museum  at  Amherst  and 
whose  origin  I  had  been  unable  to  learn.  These  "veins" 
are  formed  by  the  expulsion  of  the  biotite  from  their  area, 
the  white  quartz-feldspar  mass  being  continuous  within 
and  without  their  limits. 

The  black  gneiss  abuts,  apparently  by  a  fault,  cer- 
tainly by  a  wholly  abrupt  transition,  upon  a  band  of  the 
coarse  white,  almost  micaless,  Hinsdale  gneiss,  23  feet  wide 
below,  but  narrowing  above.  This  is  followed  by  a  bed 
of  white,  thin-bedded,  highly  crystalline  chondrodite-lime- 
stone,  with  thin  films  of  serpentine,  forming  a  beautiful 
verd  antique,  which  is  separated  by  108  feet  of  the  same 
black  Lee  gneiss  from  a  second  band  of  a  similar  limestone, 
of  which  only  29.5  feet  are  exposed.  This  is  followed  in 
the  brook  bed  at  bridge  142,  and  on  through  the  cutting, 
by  a  large  mass  of  the  dark  gneiss,  carrying  beds  of 
hornblende-schist,  until  we  come,  at  the  fourth  telegraph 
pole  from  bridge  142,  upon  the  fine  unconformity  where 
the  conglomerate-gneisses  mount  upon  the  dark  Lee  gneiss. 
Between  this  point  and  the  Bancroft  station  the  cut- 
tings expose  a  long  extent  of  contorted  and  twisted  rocks, 
where  the  beds  swing  round  from  horizontal  to  vertical 
within  a  few  feet.  Gradually  a  low  dip  eastward  predomi- 
nates, and  this  becomes  steeper,  and  a  band  of  hornblende- 
gneiss  10  feet  wide  sets  in,  and  at  the  eighth  telegraph 
pole  from  the  station,  just  at  the  signal  house,  a  boss  of 
coarse  actinolitic  rock  derived  from  the  older  limestone 
protrudes.  All  east  of  the  unconformity  is  Becket  gneiss, 
^  except  the   few   hornblende-gneiss  masses  and  the  last- 

mentioned  boss  of  actinolitic  rock,  which  are  brought  just  above  the  railroad 
level  by  the  undulations  of  the  Becket  gneiss. 


^. 


THE  COLES  BROOK  ANTICLINE. 


23 


The  Coles  Brook  uuticliue  extends  north  into  Middlefield  more  than  a 
mile  mid  a  halt',  following  the  brook  bed  for  a  hundred  rods.  It  is  well 
exposed  just  south  of  Factory  village,  by  the  roadside,  for  a  long  distance 
south  of  the  schoolhouse.  Large  bosses  of  the  coarse  limestone  appear 
here,  flanked  on  the  west  by  the  Lee  hornblendic  gneiss. 

A  still  more  instractive  section  is  exposed  halfway  between  the  two 
localities  mentioned  above,  where  the  road  going  west  from  Factory  Brook 
up  onto  the  high  ground  crosses  the  limestone  near  the  site  of  H.  Hawes's 
house  (now  destroyed).  In  the  bare  hill  opposite  this  site  the  limestone 
and  the  green  actinolitic  rock  derived  from  its  alteration  are  abundantly 


Hinsdale  Xiirrtestarte 


Pegmatite 


ISnedale  Gneiss    N30'E.75W  N6'E.90' 

ZSFT 
I  I 

Fig.  2. — Detailed  section  of  the  limestone  at  Coles  Brook. 

exposed  in  vertical  strata,  and  the  white  Becket  gneiss  can  be  seen  mantling 
over  it  in  clear  unconfoi'mity,  starting  with  steep  west  dip  on  the  west  side 
of  the  bill,  becoming  horizontal  on  the  top,  and  dipping-  easterly  down  the 
east  side.  The  true  bedding  is  in  places  replaced  by  a  secondary  vertical 
structure.  A  coarse,  rusty  muscovite-biotite-gneiss,  with  graphite  and  tour- 
maline in  quite  large  prisms  (the  equivalent  of  the  Washington  gneiss  far- 
ther west),  accompanies  the  limestone  on  either  side,  extending  east  to  the 
bend  in  the  road  and  west  to  the  house  at  the  top  of  the  hill.  Just  east  of 
this  is  a  bed  of  typical  Becket  gneiss.  In  the  yard  of  the  ruined  house  the 
mantle  of  the  Becket  gneiss  is  so  nearly  continuous  that  a  boss  of  white 
limestone  a  foot  wide  projects  from  the  ground,  and  only  a  few  feet  on 
either  side  the  Becket  gneiss  dips  away  from  it. 

Interest  attaches  to  the  fact  that  the  Becket  gneiss  is  so  strongly  meta- 
morphosed as  to  form  a  quany  stone  of  first  quality  only  in  a  narrow  band 
along  either  side  of  the  limestone  belt,  as  if  the  violent  upthrust  of  the  pre- 
Cambrian  rocks  along  this  narrow  axis  had  exerted  an  influence  upon  the 
Cambrian  gneisses  for  some  distance  outward,  producing  in  them  a  marked 


24        GEOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 

granitoid  structure,  wliicli  disappears  insensibly  as  the  beds  recede  from 
this  center. 

THE    TOLLAND   AREA. 

A  large  outcrop  of  Algonkian  limestone  occurs  on  the  roadside  in 
Eiverton,  Connecticut,  near  the  southwest  corner  of  the  Granville  quad- 
rangle,^ associated  with  a  coarse  fibrolitic  two-mica-gneiss,  which  is  charac- 
teristically Algonkian  in  the  Sandisfield  quadrangle,  next  west  of  this, 
where  it  is  a  variant  of  the  blue-quartz  gneiss.  This  fibrolite-gneiss  enters 
the  Grranville  quadrangle  at  its  southwest  coi'uer  and  runs  north  by  east,  in 
a  tapering  syncline,  to  a  point  north  of  Black  Pond  in  Tolland. 

The  rocks  often  resemble  coarse  mica-schists,  and  are  scarcely  distin- 
guishable from  the  coarse  schists  and  schistose  gneisses  on  the  horizon  of 
the  Hoosac  and  Rowe  schists,  which  lie  next  east  of  the  Becket  gneiss, 
except  that  they  contain  fibrolite  and  lie  beneath  the  Cambrian  gneisses, 
and  in  the  next  quadrangle  west  can  be  traced  into  undoubted  connection 
with  the  blue-quartz  gneisses  and  the  chondroditic  limestones. 

East  of  the  middle  of  the  town  of  Tolland,  at  0.  E.  Slocum's,^  is  a 
great  quantity  of  large  bowlders  of  a  peculiar  coarse  hornblendic  gneiss, 
often  brecciated,  with  black  hornblende,  colorless  quartz,  and  orthoclase. 
Some  masses  are  medium-grained,  some  coarse,  with  hornblendes  4  to 
5  inches  long  and  1  inch  square  at  base.  This  rock  is  mentioned  by 
President  Hitchcock,  but  I  could  not  find  it  in  place.  It  probably  was 
derived  from  the  Algonkian  anticline  to  the  west. 

PETEOGEAPHICAIi  DESCRIPTION. 

LOWER    OR    HINSDALE   GNEISS,  HINSDALE    STATION. 

The  coarse  gneiss  just  above '  the  limestone  is  granitoid  in  texture 
and  contains  in  abundance  a  fresh  black  biotite  in  large  scales,  which  in  its 
upper  layers  are  aggregated  into  concretionary  masses,  flattened-out  lentic- 
ular nodules  made  up  wholly  of  fine  scales  of  biotite  and  epidote.     These 

1  The  four-cornered  division  of  the  earth's  surface  represented  on  one  of  the  sheets  of  the  Topo- 
graphic Atlas  of  the  United  States  is  called  a  quadrangle. 

^  The  manuscript  of  this  work  was  mostly  completed  before  the  atlas  sheets  of  the  United  States 
Geological  Survey  were  issued,  and  the  citation  of  names  refer  to  those  upon  the  county  atlases  of 
F.  W.  Beers. 

• '  Stratigraphically  helow,  as  the  rocks  are  overturned. 

i 


THE  HINSDALE  (JNEISS  AND  LIMESTONE.  25 

iiodnlos  are  placed  in  laiuiuatiou  i)laues  about  30""°'  apart,  the  interspace, 
except  for  rare  thin  iihns  of  the  same,  being  made  up  of  a  dead-white  mix- 
ture of  much  feldspar  and  little  quartz,  mostly  fine  grained,  but  with  here 
and  there  large  curved  cleavage  faces  of  orthoclase  exposed.  It  contains 
pvrite  in  small  pentagonal  dodecahedrons  and  submicroscopic  zircons  of 
dark  clove-brown  color.  Under  the  microscope  the  rock  is  much  dusted 
with  minute  inclusions  which  give  it  an  opaque  white  appearance.  The 
quartz  contains  a  few  short,  straight,  black  microlites,  unlike  the  long 
rutile  needles  of  the  granites.  The  trains  of  cavities  are  very  abundant, 
and  often  run  through  several  grains  of  quartz,  suggesting  crushing.  The 
orthoclase  shows  all  stages  of  decomposition  into  epidote.  At  the  begin- 
ning the  epidote  gathers  in  small  crystals  in  the  two  cleavage  planes.  The 
microcline  is  filled  with  the  same  short,  black  microlites  as  the  quai'tz,  and 
shows  most  beautiful  microcline  structure.  The  only  place  where  a  rock 
of  this  type  appears  in  the  old  Hampshire  County  area  is  in  the  coarse  mass 
which  adjoins  the  Coles  Brook  limestone  on  the  west.  It  contains,  as  does 
the  pre-Cambrian  gneiss  of  the  Tyringham  Valley  farther  south,  a  white 
orthoclase  in  large  cleavage  plates,  which  exhibits  a  rich  blue  opalescence. 

THE    HINSDALE    LIMESTONE,   HINSDALE. 

Fifty  rods  west  of  Hhisdale  station  the  limestone  occurs  with  an 
exposed  thickness  of  25  feet  (the  top  not  seen)  and  dips  30°  E.  Eight 
hundi'ed  and  thirty  feet  farther  west,  at  a  stone  mill,  a  gray  epidotic  gneiss 
occurs,  with  strike  30°  S.  and  dip  65°  E. 

The  limestone  is  a  white  to  pink,  rather  coarse  (grains  3-5™"),  highl}^ 
crystalline  rock,  with  a  certain  translucency  in  the  grains  which  distin- 
guishes it  immediately  from  all  the  other  limestones  of  western  Massachu- 
setts and  allies  it  to  the  limestones  of  the  Adirondacks.  It  carries  coccolite, 
phlogopite,  biotite,  actinolite,  chondrodite,  pyrite,  and  magnetite.  Grenerally 
the  coccolite  or  the  chondrodite,  or  both,  are  so  abundantly  and  evenly 
scattered  through  the  mass  that  it  deserves  the  name  coccolitic  limestone  or 
chondroditic  limestone,  and  the  accessory  minerals  are  so  arranged  as  to 
give  the  mass  a  distinct  foliation,  especially  when  the  chondrodite  and 
biotite  predominate. 


26        GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

An  analysis  performed  in  the  laboratory  of  Amherst  College  by  Mr. 
F.  H.  Fitts  g-ave  the  following  results: 

Analysis  of  Hinsdale  limestone. 


Insoluble  in  HCl  . 

CaO 

MgO 

FeO 

CO, 

Total 


Per  cent. 

21.96 

41.31 

1.87 

0.68 

34.71 


100. 53 


The  chondrodite  is  disseminated  through  the  rock  in  yellow  patches 
elongate  and  parallel  to  one  another,  and  as  it  in  places  changes  into  black 
patches  by  the  admixture  with  it  of  a  green  mica  and  magnetite  the  resem- 
blance to  the  boltonite  from  Bolton,  Massachusetts,  is  striking,  especially  in 
specimens  of  the  latter  which  are  changing  to  serpentine.  In  large  masses 
it  is  a  rich  deep-red,  like  the  chondrodite  from  the  Tilly  Foster  mine.  Under 
the  microscope  the  patches  of  the  minei-al  are  seen  to  be  made  up. of  crys- 
alline  grains  fresh  and  free  from  inclusions,  and  enwrapped  by  scales  of  at 
pale-green  micaceous  mineral,  without  any  indication  that  the  one  mineral 
has  been  derived  from  the  other.  The  mineral  shows  strong  dichroism, 
honey-yellow  to  deep  red-brown.  Toward  the  surface  of  the  ledge  the 
chondi-odite  weathers  to  a  honey-yellow  opaque  mass. 

The  phlogopite  is  in  small,  thick  crystals  with  rounded  bordei's,  having 
exactly  the  same  bronzy  color  as  the  phlogopite  from  Templeton,  Canada. 
Its  crystals  are  generally  surrounded  by  a  band  of  scales  of  greenish-gray 
biotite.  Both  minerals  are  fresh,  and  there  is  no  indication  of  a  transition 
of  one  to  the  other.  The  mineral  is  optically  negative  and  has  the  same 
axial  angle  as  the  Templeton  phlogopite. 

The  biotite  is  disseminated  in  black  scales  through  some  parts  of  the 
rocks ;  at  times  as  isolated  crystals  with  rounded  contours ;  at  times  bordering 
the  phlogopite  in  greenish-gray,  matted  scales,  or  the  chondrodite  in  thinner, 
deeper-green  scales.    All  these  occurrences  are  nearly  uniaxial  and  negative. 

The  pyroxene  occurs  in  dark-green  grains  of  coccolite  scattered  through 
the  limestone  and  in  small,  stout,  limpid  emerald-green  prisms  in  the  pink 
variety  of  the  rock. 

The  magnetite  and  pyrite  are  in  small  crystals  and  crystalline  grains. 


THE  COLES  BROOK  LIMESTONE. 


27 


the  former  often  associated  with  the  choudrodite,  the  hitter  always  in  small 
complex  crystals. 

THE   COLES  BROOK   LIMESTONE. 

The  limestones  of  this  locality  are  first  noted  by  President  Hitchcock 
in  his  Final  Report^  as  occurring-  in  the  west  part  of  Middlefield  on  Pon- 
toosuc  turnpike  and  on  the  railroad  at  the  mouth  of  Coles  Brook  and  1  mile 
east.  Both  beds  are  said  to  extend  south  into  Becket,  one,  the  easterly  (?), 
appearing-  in  the  southeastern  part  of  the  town,  on  the  "Billy  Messinger" 
farm;  also  2  miles  farther  south,  on  the  old  Becket  turnpike.  It  is  a  more 
or  less  crystalline,  white,  impure  magnesian  limestone.  A  delicate  variety 
of  serpentine  is  mixed  with  the  limestone,  forming  a  beautiful  verd  antique, 
and  in  the  south  of  Becket  tremolite,  talc,  and  titanite  occur  in  it. 

The  following  analyses  are  given:  ^ 

Analyses  of  Coles  Brooh  limestone. 

[TSo  1,  Coles  Brook ;  No.  2, 1  mile  east  of  Coles  Brook  (a) ;  No.  3,  Becket,  southeastern  part ;  No.  4,  Blandford.] 


CaCO:!. 
MgCO:, 

FejO:,  . 
SiO.2... 


Sp.  gr. 


56.25 

31.56 

1.12 

U.07 


100.  00 
2.78 


88.02 
9.91 
0.15 
1.92 


100.  00 
2.71 


.58.  31 

28.61 

1.24 

11.84 


100. 00 
2.82 


51.66 

39.48 

0.91 

7.95 


100.  00 
2.77 


a  This  locality,  1  mile  east  of  Coles  Brook,  can  not  be  located.  The  analysis  contains  so  little  magnesium  and 
silicon  that  I  suppose  the  specimen  came  from  a  bowlder  of  the  Stockbridge  marble. 

I  have  added  the  analysis  of  a  limestone  from  Blandford  from  the  same 
table,  which  proves  to  be  a  bowlder,  doubtless  from  the  Becket  locality, 
and,  like  it,  contains  tremolite  and  talc.  These  large  bowlders  occur  abun- 
dantly, and  the  one  whicb  is  noted  in  the  1 841  report  as  a  ledge  of  lime- 
stone, in  the  northwest  portion  of  the  town  of  Blandford,  was  found  to  be 
a  bowlder  by  Mr.  S.  A.  Bartholomew,  who  used  it  and  many  others  in  his 
limekiln  and  traced  them  northwest  to  the  outcrops  in  Becket.  The  micro- 
scopic description  of  the  Hinsdale  station  limestones  given  above  will  apply 
wholly  to  these,  and  the  change  of  choudrodite  into  the  serpentine  may 
be  followed  better  here.     The  former  rock  is,  however,  coarser,  and  the 


'  Geol.  Mass.,  1841,  pp.  81,  85,  and  567. 


2  Ibid.,  p.  80. 


28  GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

included  minerals  are  in  larger  individuals,  and  so  better  fitted  for  mineral- 
ogical  study. 

THE  BLUE-QUARTZ    GNEISS,  PERU.' 

This  is  a  rusty,  fine-grained  gneiss,  with  little  mica  (biotite),  in  distant  flat 
sheets  of  small  scales,  and  with  greasy  blue  quartz  in  grains  and  flat  plates 
1  to  3""  thick,  which  often  coalesce  into  parallel  layers  of  considerable 
extent.  These  layers  are  plainly  secondary  infiltrations  in  a  fine-granular 
ground  which  has  the  aspect  of  a  fine  sandstone  or  quartzite.  Under  the 
microscope  this  ground  proves  to  be  an  exceedingly  fine-grained  mixture 
of  quartz,  orthoclase,  microline,  and,  in  abundance,  minute  scales  of  mus- 
covite,  and  it  is  such  a  structure  as  may  have  been  produced  by  the  crushing' 
of  a  granite  and  the  change  of  most  of  its  feldspar  into  muscovite. 

The  blue  quartz  contains  a  few  miniite  broken  rutile  needles,  rarely 
cavities  containing  small,  rapidly  moving  bubbles,  and  many  sheets  of  very 
fine  pores  or  grains  of  some  mineral.  These  are  rudely  parallel.  There  are 
a  few  distant  fissures.  A  fragment  heated  for  a  long  time  with  the  bellows 
blowpipe  retained  its  color  without  perceptible  change.  It  shows,  with 
plane-polarized  light,  small  traces  of  undulatory  polarization,  and  the 
whole  of  each  of  the  bands  of  the  blue  quartz,  however  large,  polarizes  as  a 
single  individual.  The  sections  were  cut  at  right  angles  to  the  foliation, 
but  with  what  direction  in  that  plane  I  do  not  know.  It  is  interesting  that 
in  each  case  they  are  cut  at  right  angles  to  the  optical  axis,  and  the  slide  can 
be  moved  from  one  end  to  another  of  the  blue-quartz  bands — 1-2™™  wide, 
15°"°  long — and  the  optical  figure  remains  sharply  defined,  regular,  and 
unchanged,  which  would  seem  to  militate  against  the  explanation  of  the  color 
as  due  to  strain. 

It  is,  however,  a  very  remarkable  fact  that  these  slides  still  show  the 
lavender  color  distinctly  with  transmitted  light  when  examined  with  the  lens 
or  the  eye  alone,  in  spite  of  the  fact  that  it  is  of  so  pale  and  dilute  a  charac- 
ter that  one  would  not  expect  to  see  it  in  so  thin  a  film.  Moreover,  narrow 
bands,  at  times  branching,  run  across  the  colored  layers,  in  which  the  color 
is  wholly  wanting;  and  these  bands,  when  examined  in  polarized  light,  are 
made  up  of  a  fine  mosaic  of  quartz  fragments.  It  is  thus  plain  that  the 
blue  color  is  due  to  the  state  of  tension  in  which  the  quartz  is  held,  and 
disappears  when  this  tension  is  reheved  by  rupture  across  the  mass. 

1  Residence  of  H.  A.  Messenger. 


PETEOGRAPHICAL  DESCRIPTION.  29 


THE    LEE    GNEISS. 


Amphlhollte  from  Wasliiiigton.^  Black,  fine-grained,  distinctly  bedded 
rock.  Microscopic  hornblende  abundant  in  small,  thin  plates,  of  medium 
absorption  and  pleoclu'oism.  c=b>a;  empale  indig-o;  lv=olive;  a=pale 
ocher.  Menaccanite  in  large,  shapeless  masses,  with  broad  border  of 
leucoxene,  abundant;  little  biotite. 

The  common  feldspathic  mosaic  forming  the  groundmass  of  the  rock 
is  so  covered  up  by  the  hornblende  blades  and  of  so  fine  grain  that  it  is 
not  possible  to  determine  the  variety  of  plagioclase  which  is  present.  There 
is  not  the  sHghtest  trace  of  cleavage  or  twinning,  and  thus  there  is  small 
ground  to  suppose  the  rock  to  have  been  greatly  influenced  by  shearing  forces. 
At  the  same  time,  the  separate  rounded  or  polygonal  grains  of  which  the 
mosaic  is  composed  show  quite  uniformly,  when  examined  with  plane- 
polarized  light,  a  form  of  undulatory  polarization  which  I  have  called  in 
the  following  notes  concentric  polarization.  A  single  grain  becomes  black, 
first  at  the  border,  and  the  darkening  advances  regularly  toward  the  center, 
and  it  sometimes  requires  a  rotation  of  45°  to  render  the  whole  fragment 
dark.  At  times  such  a  fragment  is  cracked  into  several  parts  without 
disturbing  the  regularity  of  the  above  process. 

In  the  absence  of  cleavage  and  twinning  it  is  not  possible  to  think  of 
this  as  a  result  of  strain  from  the  external  forces  which  have  deformed  the 
rock.  It  also  is  without  the  banded  zonal  arrangement  which  usually 
accompanies  changes  of  chemical  composition,  and  where  a  distinct  crystal 
has  been  broken  up  into  such  a  mosaic  the  fragments  show  this  peculiarity 
in  a  striking  manner.  It  is  a  structure  characteristic  of  the  whole  series  of 
amphibolites  described  in  the  following  pages,  and  especially  of  several  forms 
which  are  certainly  derived  from  limestones.  This  amphibolite  preserves  no 
residual  structures  pointing  to  an  eruptive  origin.  It  is  a  long,  interbedded 
stratum,  parallel  with  and  near  to  the  Hinsdale  limestone,  and  it  is  a  distinct 
associate  of  this  rock  and  reappears  with  it  in  the  Coles  Brook  band.  It 
occurs  also  as  a  continuation  of  the  limestone  seen  on  the  Alderman  farm  in 
Becket,  where  in  one  place  the  limestone  is  changed  into  white  tremolite- 
schist  for  7  feet  in  from  the  contact  and  in  another  into  black  amphibolite. 
It  is  also  seen  at  the  interesting  outcrop  in  Middlefield  described  above; 

'  C.  F.  Lyman's  pasture,  east  of  the  graphite  mine. 


30  GEOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 

and  the  same  is  true  throughout  Berkshire  County.^  I  think  it  probable 
that  the  rock  was  derived  from  an  impure  Hmestone,  but  must  leave  its  ori- 
gin in  doubt,  because  no  lithological  criteria  can  be  found  that  will  distin- 
guish amphibolites  derived  from  lavas  or  tuffs  and  those  derived  from 
impure  limestones.  In  the  succeeding  sections  treating  of  the  amphibolites, 
to  which  reference  may  be  made  (see  Chapter  X),  only  those  from  the  east 
of  the  river  in  Leverett  have  shown  distinct  residual  characteristics  peculiar 
to  eruptives  and  comparable  to  those  found  in  the  altered  eruptives  of  the 
Baltimore  (Maryland)  area  and  of  several  foreign  localities. 

RESUME. 

These  oldest  gneisses  are  coarse,  often  very  coarse,  often  granitoid, 
and  the  cleavage  surfaces  of  the  large  microclines  are  strongly  curved. 
Allanite  is  very  generally  distributed,  at  times  abundant. 

The  chondrodite-phlogopite-limestones  are  characteristic. 

The  upper  gneisses,  often  strongly  foliated,  are  marked  by  the  universal 
distribution  of  graphite,  at  times  so  abundant  as  to  tempt  mining,  and  by 
the  abundance  of  the  peculiar  blue  quartz,  of  hornblende,  and  of  iron  rust. 
Allanite  is  even  more  abundant  here. 

I  Professor  Kemp  haE  recently  called  attention  to  the  fact  that  similar  black  hornblendic  rocks 
are  constant  attendants  of  the  pre-Camhrian  limestones  of  the  Adirondacks,  fringing  the  beds  both 
above  and  below.     Geol.  Moriah  and  Westport :  Bull.  N.  Y.  State  Museum,  Vol.  Ill,  1895,  p.  329. 


CHAPTER  V. 

THE  LOWER   CAMBRIAN   GNEISSES. 

THE  BECKET   CONGLOMERATE-GNEISS. 

This  gneiss  skirts  the  western  border  of  Ham^jshire  and  Hainpden 
counties,  inclosing  narrow  strips  of  Algonkian  rocks  in  Middlefield  and 
Tolland,  and  stretches  westward  across  the  first  two  tiers  of  towns  in 
Berkshire  County,  around  many  pre-Cambrian  areas,  to  enter  into  most 
complex  and  obscure  relations  to  the  Stockbridge  limestone  and  associated 
rocks  of  western  Berkshire.  It  is  thus  much  more  amply  developed  beyond 
the  boundaries  of  the  river  counties  than  within  them,  and  I  have  for 
convenience  given  it  a  name  from  the  town  in  Berkshire  where  it  may  be 
best  studied.  It  rests  upon  the  older  gneiss  in  great  beds  of  highly  altered 
quartz-conglomerate,  as  at  the  Hoosac  Tunnel  central  shaft  and  at  the 
Dalton  Clubhouse,  and  graduates  in  its  upper  portion  into  the  Cheshire 
quartzites,  so  largely  used  for  glass-making.  The  rock  is  unconformable 
upon  the  lower  series. 

With  many  exceptions,  especially  where  it  folds  round  the  older  rock, 
as  given  in  detail  below,  the  strike  is  the  prevailing  one  of  the  region, 
varying  but  little  from  north  and  south,  and  the  dips  are  high. 

CONTACT   UPON  THE  WASHINGTON   GNEISS   BELOW. 

As  it  passes  down  the  eastern  side  of  the  area  of  older  rock  in  Hins- 
dale it  dips  away  from  it  with  some  irregularity,  which  is  confined  to  the 
immediate  vicinity  of  the  contact ;  farther  away  it  regains  the  normal  north- 
south  strike  and  a  dip  which  varies  but  little  from  verticality  for  long  dis- 
tances. As  it  swings  around  the  southern  end  of  the  underlying  gneiss  it 
dips  away  from  it  with  low  angles,  changing  from  east  thi'ough  south  to 
west,  and  it  is  at  the  same  time  so  far  affected  by  the  strong  east-west  com- 
pression which  has  molded  the  whole  region  that  it  is  thrown  into  a  series 
of  subordinate  folds  with  axes  radiating  outward  and  pitching  from  the  old 
gneiss,  which  has  thus  assumed  the  role  of  a  foreign  and  more  resistant 

31 


32  (GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

body  during  the  later  folding  of  the  newer  gneiss.  This  is  well  seen  along 
the  railroad  from  above  Becket  to  Bancroft  station,  in  Middlefield,  where 
one  passes  four  principal  anticlines  with  their  intervening  synclines,  as  well 
as  many  subordinate  flexures,  all  pitching  southward. 

DESCRIPTION   OF  THE   ROCK. 

The  prevailing  rock  is  a  rather  fine-grained  biotite-gneiss,  always  in 
some  degree  friable  and  breaking  crisply,  and  without  the  extremely  firm 
texture  of  the  older  series.  Sometimes  it  is,  while  seemingly  quite  fresh, 
so  softly  saccharoidal  as  to  crumble  under  the  pressure  of  the  fingers,  and 
ao-ain  so  brittle  that  a  blow  of  the  hammer  will  punch  a  square  hole  in  the 
middle  of  a  thin  slab  without  cracking  it.  It  shows  clear  gray  shades, 
dependent  for  their  depth  upon  the  amount  of  the  biotite  present,  which  is 
in  clear  black  to  dark-brown  scales,  both  the  feldspar  and  the  quartz  being 
colorless,  limpid,  and  much  fissured.  It  contains  very  few  accessory  min- 
erals and  only  small  and  unimportant  veins  of  coarse  granite.  It  varies 
from  a  very  thin-fissile  rock — "scaly,"  the  quarrymen  call  it — to  a  fine- 
grained granitoid-gneiss,  furnishing  a  quarry  stone  of  the  first  quality,  equal 
to  anything  in  New  England  for  all  kinds  of  monumental  work. 

It  is  best  exposed  for  study  along  the  Boston  and  Albany  Railroad 
below  Becket  station,  and  a  brief  description  of  this  section  will  give  a 
o-ood  view  of  the  range  of  variation  in  the  rock,  although  it  must  be  noted 
that  the  section  is  not  taken  at  right  angles  to  the  dip,  and  that  it  contains 
several  repetitions  of  the  same  strata,  as  the  folds  around  the  older  gneiss 
are  traversed. 

From  Becket  station  east  to  the  Middlefield  line  the  older,  rusty,  pre- 
Cambrian  gneiss  with  small  segregated  granite  veins  continues,  passing  three 
brido-es,  and  changes  here  immediately  into  a  light-colored,  fine-grained 
granitoid  gneiss,  which  continues  a  long  distance  to  the  next  (fourth) 
brido-e,  becoming  gradually  bedded.  The  change  takes  place  across  the 
strike,  and  the  rock  dips  70°  E. ;  the  passage  being  apparently  from  lower 
to  hio'her  beds.  A  little  farther,  east  of  the  next  (fifth)  bridge,  and  thus 
still  higher  up,  a  stratum  of  thin  and  wavy  bedded  muscovite-gneiss  occurs, 
which  is  quite  exceptional  so  far  east  in  this  series.  Then  for  a  long  dis- 
tance a  "scaly"  biotite-gneiss,  often  subporphyritic  and  rusting  from  the 
abundance  of  the  pyrite  which  is  disseminated  through  it,  runs  on  in  great 


THE  BEOKET  CONGLOMEEATE-GNEISS.  33 

folds,  the  general  strike  coincidiug  with  the  course  of  the  railroad,  until  the 
large  quarries  on  the  north  side  of  the  road  are  reached.  These  were  worked 
in  1887  by  the  Clark  Hill  Granite  Company,  Mr.  J.  H.  Adams,  of  Dalton, 
being  the  principal  owner. 

1  am  indebted  to  the  superintendent,  Mr.  Hopkins,  of  Becket,  who 
opened  some  of  the  first  quarries  in  the  region,  for  much  information  con- 
cerning the  working  of  the  quarry.  Besides  supplying  much  rough  stone  to 
the  railroad  and  shipping  many  paving  stones  to  Holyoke  and  other  cities, 
this  quarry  furnishes  a  fine,  light-colored  granite  of  medium  grain,  obtainable 
in  large  blocks  and  suitable  for  all  the  uses  of  architecture,  and  a  finer- 
grained,  darker  stone  of  very  even  grain,  which,  if  it  can  be  quarried  in  as 
large  blocks  as  the  bed  promises  from  surface  indications,  will  be  very  valu- 
able as  a  monumental  stone  and  for  all  the  finer  classes  of  work  for  which 
granite  is  employed  where  its  somewhat  somber  shade,  when  polished,  is 
not  objectionable.  The  "granite"  extends  far  north  into  Clark  Hill,  on  the 
south  slope  of  which  these  quarries  extend  for  a  long  distance,  parallel  to 
the  railroad,  and  crosses  the  river  to  the  south  into  Becket,  where  also  are 
quarries.  Some  small  segregated  veins  and  lenses  of  pegmatite  cut  the 
rock  at  the  quarry. 

The  bedding  of  the  granitoid  gneiss  of  the  quarry  can  be  clearly  seen,, 
and  is  nearly  horizontal,  corresponding  with  the  more  plainly  foliated  rock 
adjacent,  along  the  railroad,  which  seems  certainly  to  grade  into  the 
quarry  rock. 

Between  the  next  two  bridges  is  again  a  great  development  of  the  same 
granitoid  gneiss,  followed  by  a  thin,  flat-bedded  gneiss,  banded  in  gray  and 
reddish  layers.  Another  band  of  the  fine-grained  granitoid  gneiss  separates 
this  in  the  western  entrance  of  the  Coles  Brook  cut  from  the  heavy,  dark 
gneisses  of  the  Algonkian.     (See  section,  fig.  1,  p.  22.) 

DISTRIBUTION. 

The  rocks  of  this  series  occupy  the  western  part  of  Middlefield,  which 
is  in  Hampshire  County,  but  beyond  the  limit  of  the  map,  and  stretch 
across  Becket,  which  is  in  Berkshire  County.  The  broad  band  of  workable 
granitoid  gneiss  seems  to  be  continuous  across  the  whole  length  of  Becket, 
and  it  is  used  extensively  by  the  Chester  Granite  Company,  which  obtains 
its  materials  from  quarries  in  the  eastern  part  of  Becket,  not  far  south  of  the 

MON  XXIX 3 


34  GEOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 

road  running  west  from  Chester  station.  This  company  has  ah-eady  put 
upon  the  market  a  large  quantity  of  stone  of  the  first  quahty.  The  rock  is, 
when  pohshed,  a  clear,  dark  gray — too  dark  for  many  purposes — and  when 
left  with  a  rough  surface  is  almost  white,  producing  a  marked  contrast 
where  the  two  kinds  of  surface  are  juxtaposed.  The  "sap"  of  the  stone  in 
the  quarry  is  thin  and  white,  showing  it  to  be  very  durable,  and  the  pyrite, 
which  exists  in  small  grains,  seems  not  to  be  subject  to  oxidation,  unlike 
that  in  the  thin-bedded  portions  of  the  same  rock.  If  it  shall  prove  equally 
changeless  in  the  worked  surfaces  after  long  exposure,  the  deposit  is  of  great 
importance,  as  flawless  blocks  of  the  largest  dimensions  can  be  obtained, 
and  the  extent  of  the  quarry  rock  is  very  great. 

The  gneiss  enters  the  area  of  the  map  again  at  the  northwest  comer  of 
Blandford  and  extends,  with  similar  characteristics,  down  the  western  side 
of  the  town,  widening  to  the  east  so  as  to  occupy  the  whole  width  of  Tolland 
and  half  that  of  Granville. 

Following  the  band  across  Blandford,  one  finds  it  supper  portion,  nearest 
the  mica-schist,  to  be  everywhere  thin-fissile,  rusty,  contorted,  and  more  or 
less  shot  through  by  granitic  veins;  and  where  it  widens  out  to  the  south 
the  increased  area  seems  to  be  occupied  by  these  upper  thin-fissile  biotite- 
gneisses  and  worthless  rocks,  and  west  of  Tolland  the  granitoid  gneiss 
either  passes  down  or  has  run  out  entirely. 

In  some  places  in  Tolland  the  rock  approaches  so  closely  the  most 
feldspathic  vaiiety  of  the  next  series — at  the  blacksmith  shop  in  the  village 
even  containing  large  garnets — that  I  have  questioned  whether  one  or  more 
folds  of  this  series  are  not  included  in  the  older  gneisses. 

It  extends  south  into  Connecticut  as  the  western  part  of  Percival's  K  2,^ 
from  which,  on  the  east,  the  mica-schist  is  not  separated.  Far  to  the  east 
the  same  gneiss  rises  again  from  beneath  the  hydromica-schists  east  of 
South  Mountain,  in  the  southern  portion  of  Granville.  It  is  here  a  gran- 
itoid gneiss  of  the  common  type,  which  extends  southward  into  Connecticut, 
and  is  marked  1 2  upon  Percival's  map. 

PETROGRAPHICAL    DESCRIPTION. 

1.  Granitoid  gneiss  from  Clark  Hill  quarries,  Middlefield.  "Finest 
quarry  stone." 


•J.  G.  Percival,  Kept.  Geol.  Conn.,  1842,  p.  113. 


THE  BECKET  CONGLOMERATE-GNEISS.  35 

A  line-g-rained  biotite-granitoid  gneiss  of  gray  color,  with  shade  of 
brown.  The  deep-brown  biotite  is  scattered  through  a  fresh  colorless  mix- 
tui-e  of  quartz  and  feldspar.  Titanite  is  so  abundant  as  almost  to  deserve 
place  as  an  essential  constituent.  The  lens  shows  a  wholly  even-grained, 
very  dusty  mass. 

Under  the  microscope  the  quartz  is  characterized  by  the  small  number 
of  inclusions  it  contains,  rarely  fluid  pores  with  large,  slow-moving  bubbles 
in  the  largest  grains.  The  long  rutile  needles  are  wholly  absent;  stout, 
flat  muscovite  microlites  occur.  Orthoclase  appears  in  large,  clear  grains. 
Microchne  is  the  most  abundant  and  the  most  recent  feldspathic  con- 
stituent. 

Biotite  in  deep  greenish-brown,  jagged  grains  fits  itself  to  all  the  other 
constituents,  and  so  is  of  later  formation. 

Muscovite  appears  in  small  quantity  under  the  microscope. 

Titanite  appears  in  large,  well-formed  crystals,  wine-yellow,  and  in 
abundant  smaller,  irregular-clustered  grains. 

Minute  zircons,  highly  refractive,  elongate,  with  rounded  outlines,  are 
not  rare. 

Magnetite  and  titanic  iron  are  wholly  absent. 

2.  Granitoid  gneiss   from   Clark   Hill   quarries,   Middlefield.     Coarse 

quarry  stone. 

A  medium-grained,  light-gray  muscovite-biotite-granitoid  gneiss,  whose 
clearer  color,  as  compared  with  the  preceding,  is  produced  by  the  increase 
in  the  size  of  grain  of  the  other  constituents,  while  the  mica  does  not  increase 
in  size  or  quantity.  The  lens  shows  larger,  limpid  grains  scattered  in  a 
disconnected,  granular,  dusty,  and  micaceous  groundmass,  which  is  identical 
with  the  whole  mass  of  the  preceding  variety. 

The  quartz  rarely  includes  rutile  needles,  and  contains,  especially  in 
the  larger  grains,  sheets  of  pores,  often  negative  crystals,  a  few  with  large 
motionless  or  slow-moving  bubbles. 

The  orthoclase  is  in  subporphyritic  masses,  rendered  turbid,  as 
usual,  by  an  opaque  white  substance  (kaolin?),  which  also  occurs  as  an 
exquisite  dendritic  growth  thrust  out  among  the  fissures  between  the  quartz 
grains  and  appearing  black  by  transmitted  and  silvery  white  by  reflected 
light. 

In  one  quadrangular  section  of  orthoclase  cut  about  parallel  to  oo  P  cb 


36        GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

(010)  a  great  number  of  sheets  of  fluid  pores  with  moving-  bubbles  appear, 
arranged  part  parallel  to  0  P  (001)  and  part  parallel  to  go  P  (110). 

Microcline  is  abundant,  with  microperthitic  structure. 

A  plagioclase  near  albite  occurs. 

The  biotite  is  deep  red-brown. 

Muscovite  appears  abundantly,  in  microscopic  scales. 

Titanite  is  very  abundant  in  congeries  of  grains,  in  one  or  two  cases 
inclosing  a  grain  of  menaccanite. 

Zircon  appears  in  regular  square  prisms  P  (111)  «>  P  (HO),  colorless. 

3.  Granitoid  gneiss,  Becket.  The  best  quarry  stone  of  the  Chester 
Granite  Company. 

Of  slightly  coarser  grain  than  the  best  stone  at  the  Clark  Hill  quarry, 
and  of  clear  gray  color — a  muscovite-biotite-gneiss.  The  lens  shows  larger 
limpid  grains  in  a  porphyritic  granular  groundmass,  which  contains  all  the 
biotite  and  is  somewhat  dusty. 

The  larger  grains  are  mostly  quartz,  without  rutile  needles,  and  with 
minute  fluid  inclusions  showing  motionless  bubbles  of  elongate  shapes. 

Orthoclase  occurs  in  rare,  large  grains,  much  dusted. 

Microcline  is  in  secondary  growths  cementing  a  great  number  of  grains 
together.     It  is  very  fresh. 

Plagioclase  is  rather  rare. 

The  biotite  is  deep  greenish-brown. 

Titanite  is  visible  with  a  lens,  but  is  present  in  only  small  quantity 
in  the  slide. 

No  zircon  or  magnetite  occurs. 

CRUSHING  TESTS. 

Prof.  J.  F.  Kemp  has  given  ^  some  valuable  facts  in  regard  to  the 
granite  quarried  by  the  Hudson  and  Chester  Granite  Company  at  Becket, 
Massachusetts.     He  says: 

"An  analysis,  which  is  the  mean  of  two  closely  agreeing  duplicates,  was 
made  by  Prof.  L.  M.  Dennis,  of  Cornell  University,  and  the  soda  is  given 
by  difference,  because  in  the  NH^Cl  and  CaCOg  used  in  the  determination 
of  the  alkalies  some  sodium  was  shown  by  the  spectroscope. 

'  Trans.  New  York  Acad.  Sci.,  Vol.  XI,  p.  4. 


CKUSniNG  TESTS  OP  THE  BECKET  GRANITOID  GNEISS. 
Analysis  of  granite  from  quarries  at  Becket,  Massachusetts. 


37 


Moisture  at  110°  C 
Loss  on  ignitiou... 

SiO, 

Fe,0;,  

A1..0;, 

MuO 

CaO 

MgO 

KjO 

S 

NajO  by  difference 


Per  cent. 

0.08 

.74 

69,  465 

2.30 
17.50 
Trace. 

2.57 

.305 

4.07 
.04 


97.07 
2.93 


"Crushing  tests  were  made  on  five  sample  cubes  with  the  Emory  testing 
machine  in  the  School  of  Mines,  and  as  preparatory  to  this  the  specific 
gravity  was  found  on  four  cubes  at  2.688,  2.687,  2.684,  and  2.688.  After 
three  weeks'  soaking  these  cubes  absorbed  water,  respectively,  0.0021, 
0.0021,  0.00224,  and  0.0026  per  cent.  The  cubes  were  first  ground  and 
polished  so  that  the  faces  next  the  jaws  of  the  crusher  were  parallel  within 
a  limit  of  error  of  0.005  inch.  The  cushion  employed  between  the  cubes 
and  the  jaws  was  blotting  paper.  The  crushing  tests  gave  the  following 
results: 

Crushing  tests  of  granite  from  quarries  at  Becket,  Massachusetts, 


Height inches.. 

Breadth inches . . 

Thickness inches . . 

Area sq.  inches.. 

Maximum  compression pounds . . 

Crushing  strength per  sq.  inch . . 


2.033 
2.0 
2.1 
4.2 
113,  200 
26,  952 


II. 


1.983 
2.13 
1.99 
4.23 
122,000 
28, 841 


III. 


2.059 
2.02 
2.03 
4.1 
106, 000 
25,  853 


IV. 


2.011 
1.97 
2.03 
4.0 
101,  400 
25,  350 


2.009 
2.03 
2.03 
4.12 
108,  700 
26, 383 


' '  The  cubes  exploded  without  previous  cracking.  This  strength  is  excep- 
tionally high,  as  the  general  run  of  granite  is  far  less.  It  does  not,  however, 
equal  the  elaiolite-syenite  of  Little  Rock,  Arkansas,  which  was  tested  by  the 
late  J.  Francis  Williams  (see  Annual  Report  of  Arkansas  State  Geologist, 


38        GEOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 

1890,  Vol.  II),  where  results  of  over  30,000  pounds  were  obtained;  but  it  is 
far  beyond  the  requirements  of  building. 

"Cubes  of  the  rock  were  also  boiled  in  acid.  One  which  was  thus 
treated  for  five  hours  in  boiling  dilute  HCl  (1  part  HCl  of  specific  gravity 
1.20  to  20  parts  HgO)  lost  0.59  per  cent  in  weight.  A  second  cube  treated 
in  the  same  way  in  boiling  dilute  H2SO4  (1  part  H2SO4  of  specific  gravity 
1.84  to  20  parts  HjO)  gave  a  loss  of  0.48  per  cent.  Both  these  results  indi- 
cate a  great  resistance  to  natural  solvents.  Two  large  cubes  were  placed  in 
a  muffle  and  maintained  at  a  bright  red  for  half  an  hour.  One  was  allowed 
to  cool  just  below  redness  and  then  plunged  in  cold  water.  It  caused 
one  crack  that  extended  half  through.  The  other  cube  was  allowed  to 
cool  slowly  in  the  air,  and  showed  a  thin  external  crumbling  layer.  When 
these  results  are  compared  with  somewhat  similar  tests  of  other  granites,  as 
set  forth  by  Mr.  Gr.  P.  Merrill  in  his  valuable  work,  Stones  for  Construction 
and  Ornament,  and  with  others  in  Vol.  I  of  the  Final  Report  of  the  Geo- 
logical Survey  of  Minnesota,  and  others  by  Dr.  A.  W.  Jackson  in  the  recent 
annual  reports  of  the  State  mineralogist  of  California,  it  appears  that  the 
Chester^  stone  endured  well." 

THE   GISTEISS  AT  SHEIiBUR]SnE. 

The  oval  area  of  gneiss  on  the  Deerfield  Eiver,  at  Shelburne  Falls, 
has  long  attracted  attention  as  a  very  striking  illustration  of  erosion.^  It  is 
a  regular  quaquaversal.  The  gneisses  in  the  center  of  the  area  are  in  the 
main  horizontal,  though  much  contorted.  Toward  the  borders  they  dip 
under  a  bed  of  hornblende-schist,  which  frames  them  beautifully,  and  this 
schist  in  turn  dips  outward  on  all  sides  beneath  the  mica-schists,  and  these 
dip  outward  also,  with  gradually  increasing  inclination. 

The  erosion  which  wore  through  the  newer  beds  domed  over  the  gneiss 
has  cut  more  rapidly  into  it,  so  that  the  gneiss  occupies  now  the  bottom  of  a 
deep  circular  basin  and  rises  high  up  the  sides  of  the  surrounding  hills,  where 
it  is  capped  by  the  newer  beds.  This  basin  is  cut  across  by  the  Deerfield 
River  and  its  tributary,  the  North  River. 

The  rock  is  very  largely  a  biotite-gneiss  of  medium  grain,  granitoid  and 
light-gray,  as  at  the  quarry  by  the  railroad  on  the  western  boundary  of  the 

1  This  should  be  Becket ;  the  quarries  of  the  company  are  in  Becket  and  the  workshops  in  Chester. 
2E.  Hitchcock.     "Ten  thousand  feet  of   vertical  thickness  have  disappeared."     Elementary 
Geoloji.v,  I860,  p.  121. 


THE  GNEISS  AT  SHELBUENE.  39 

outcrop.  Here  it  is  not  to  be  distinguished  from  the  Becket  or  Monson 
gneiss.  Under  tlie  microscope  it  is  so  fresh  that  the  quartz  and  feldspar 
aj-e  scarcely  visible  without  polarizer.  Below  the  falls  the  gneiss  is  greatly- 
dislocated,  and  many  varieties  alternate  in  much  confusion.  A  white  bio- 
tite-granitoid  gneiss  is  followed  conformably  by  a  similar  but  thin-bedded 
rock.  These  are  faulted  against  a  greenish  gneiss  containing  many  inter- 
mixed fragments  of  schist,  and  against  this  rests  the  contorted  hornblende- 
gneiss  which  furnished  the  beautiful  bowlder  now  adorning  the  vestibule 
of  the  geological  museum  at  Amherst,  which  was  figured  by  President 
Hitchcock.^  The  rock  is  made  up  of  thin  bands  of  a  very  hornblendic 
gneiss,  alternating  with  equally  thin  bands  of  a  white  gneiss,  and  the  whole 
folded  with  a  remarkable  complexity.  On  the  south  side  of  the  stream  the 
black  hornblende  rock  rests  upon  the  biotite-gneiss  exactly  as  it  does  on  the 
top  of  Bald  Mountain  (now  called  Massaemet),  and  it  is  not  impossible  that 
the  deep  basin  has  been  formed  by  a  sinking  of  its  bottom  about  1,200  feet. 
Bald  Mountain  is  the  eastern  border  of  the  basin. 

Toward  the  southwest  of  the  area  the  rock  is  a  thin-bedded  biotite- 
hornblende-gneiss  with  few  garnets  and  with  pyrite. 

At  the  contact  under  the  bridge  on  the  road  to  Charlemont  the  rock  is 
a  rather  fine-grained,  thin-fissile  biotite-gneiss,  with  few  red  garnets  and 
some  thick,  compact  quartzose  beds.  Above  this  is  a  very  cortorted  horn- 
blende-gneiss. On  the  road  south  from  Shelburne  Falls  along  the  east  side 
of  the  river,  and  near  the  south  border  of  the  gneiss,  the  latter  wraps  around 
a  great  mass  of  hornblende-schist,  as  if  it  were  a  granite  rather  than  a  gneiss. 

It  is  with  some  reserve  that  I  identify  this  gneiss  with  the  Becket  and 
Monson  gneisses.  The  gray  gneiss  can  not  be  distinguished  from  the  upper 
portion  of  the  Monson  gneiss,  except  that  it  is  not  "stretched."  The  thin- 
bedded  hornblendic  gneiss  in  many  ways  suggests  the  idea  that  it  is  devel- 
oped from  the  hornblende-schists  which  surround  and  once  capped  the 
gneiss,  and  it  is  unlike  the  hornblendic  layers  in  the  Monson  gneiss.  I  have 
been  brought  to  weigh  these  matters  with  care  because  of  a  more  serious 
difficulty.  At  the  Groshen  antichne,  next  south,  the  calciferous  mica-schists 
are  broken  through,  and  we  have  the  normal  section  in  descending  order: 

1.  Corrugated  schists = Conway  schist.  ^  Calciferous  mica-schist. 

2.  Flags=Goshen  schist.  ) 

3.  Chloritic  and  hornblende-schists=:Hawley  schist. 


IE.  Hitchcock,  Elementary  Geology,  1860,  p.  26. 


40        GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

Going  west  across  Groshen  and  Cummington,  we  find  the  same  series 
repeated  and  carried  still  lower,  thus: 

4.  The  upper  sericite-schist=Eowe  schist. 

5.  The  hornblende- serpentine  band=Ohester  amphibolite. 

6.  The  lower  sericite-schist=Savoy  schist. 

7.  The  feldspathic  mica-schist=Hoosac  schist. 

8.  The  Becket  gneiss. 

Now  in  the  Shelburne  anticline  one  passes  directly  from  the  corrugated 
schists  (1)  to  the  gneiss  (8),  with  only  the  intervention  of  a  single  horn- 
blende band,  often  not  more  than  50  feet  tliick,  and  this  bed  thus  replaces 
the  Groshen  flags  and  the  whole  sericite-schist  series. 

It  is  true  that  the  first  bed  of  limestone  above  the  hornblende-schist  is 
white  and  slightly  actinolitic,  but  it  has  a  border  of  hard,  black  hornblende- 
garnet  rock,  so  characteristic  of  the  limestones  of  the  Conway  schist.  An 
inspection  of  the  map  will  show  that  the  normal  succession  of  the  beds 
occurs  across  Shelburne  exactly  as  across  the  towns  north  or  south  of  the 
Shelburne  gneiss,  from  which  one  is  inclined  to  hesitate  between  three  sup- 
positions: (1)  That  the  Shelburne  rocks  are  the  sericite-schist  (4  to  6  above) 
grown  feldspathic;  (2)  that  all  the  beds  of  the  flagstone  and  sericite-schist 
series,  so  abundantly  developed  just  to  the  west,  have  thinned  out  to  the  east, 
so  that  they  are  represented  only  by  the  thin  hornblende  band;  and  (3)  that 
the  granitoid  gneiss  is  an  intrusive  rock  grown  gneissoid  by  pressure.  I 
am  inclined  to  accept  the  second  supposition,  as  the  hornblende-schist  is 
almost  certainly  the  continuation  of  the  Hawley  schist,  and  one  may  assume 
that  the  gneisses  formed  an  island  larger  than  the  present  exposure  during 
the  deposition  of  the  sericite-schists  and  the  flagstones.  The  diminished 
thickness  of  these  two  series  east  of  the  Connecticut  harmonizes  with  this 
assumption.     The  coloring  adopted  on  the  map  accords  with  this  hypothesis. 

Contacts. — Groing  south  along  the  west  side  of  the  river  into  Conway, 
20  rods  north  of  L.  W.  and  B.  A.  Andrews's  house,  one  passes  for  a  long 
distance  over  a  thick-bedded,  white  biotite-gneiss,  and  finds  this  changing, 
in  the  hillside  west  of  the  road,  into  a  thin-bedded  hornblende-biotite-schist 
with  garnets  and  pyrites. 

The  transition  is  sudden  to  the  hornblende-schist  above,  and  the  two 
rocks  are  not  separated  by  any  fissure,  but  are  welded  together  intimately. 
The  schist  is  a  thin-bedded  hornblende-schist  with  few  garnets,   black, 


THE  MONSON  GNEISS  AND  ASSOCIATED  KOCKS.  41 

lustrous,  with  some  beds ,  gneissoid  and  some  marked  by  the  absence  of 
liornblende  from  spots  which  appear  Hke  porphyritic  feldspars  but  are 
composed  of  a  granular  feldspathic  mass.  At  the  top  of  the  hornblende- 
schist  the  contact  is  also  visible,  and  the  change  is  sudden  into  a  rather 
coarse,  slightly  rusty,  gray  muscovite-schist  with  few  garnets. 

Directly  across  the  river,  back  of  J.  Dole's  house,  the  rather  coarse 
white  gneiss  is  followed  immediately  by  an  arenaceous  hornblende-schist, 
gneissoid  as  before,  and  this  is  separated  from  the  mica-schist  above  by  a 
small  mineral  vein. 

THE  MONSOK  GNEISS  AND  ASSOCIATED  BOCKS. 

Amos  Eaton  says,^  referring  to  the  gneiss  range  east  of  the  river: 
"This  range  evidently  passes  under  the  Connecticut  River,  accompanying 
the  granite  and  covered  by  other  strata,  and  rises  with  it  on  the  western 
side,"  and  I  have,  myself,  no  hesitation  in  associating  the  bands  of  gneiss 
which  cross  the  State  east  of  the  Connecticut  with  the  Becket  gneiss  on  the 
west  of  the  river,  on  both  lithological  and  stratigraphical  grounds.  They 
are,  however,  nowhere  known  to  come  into  visible  contact,  and  in  default 
of  this  final  proof  of  their  identity  I  may  consult  convenience  and  give 
this  rock  also  a  separate  name  and  treatment.  It  is  the  C  4  of  Percival.^ 
Beginning  north  of  the  great  bend  of  the  Connecticut,  opposite  Middletown, 
it  runs  north,  and  in  a  quaiTy  at  Portland,  to  which  I  was  kindly  guided 
by  Prof.  WilHam  North  Rice,  of  Middletown,  it  is  so  exactly  like  its  con- 
tinuation farther  north  that  in  hand  specimens  and  in  mass  it  could  not  be 
distinguished  from  the  products  of  the  quarries  of  Monson  or  Pelham.  It 
enters  the  State  from  the  south  in  two  narrow  bands,  separated  by  newer 
rocks,  and  the  eastern  band  is  limited  on  the  east  by  the  deep  sand-fiUing  of 
the  central  valley  of  Monson. 

The  two  bands  of  this  rock,  separated  by  an  infolded  complex  of 
hornblende-  and  mica-schists,  and  bounded  also  on  the  west  by  a  repeti- 
tion of  the  latter,  may  be  followed  across  Monson  and  Wilbraham  into 
Palmer.  Here  they  are  all  twisted  together  in  extreme  metamorphism  to 
form  the  hornblendic  border  of  the  intrusive  tonalite  (syenite,  Hitchcock), 
from  which  they  extricate  themselves  in  the  latitude  of  Belchertown  village, 


'Index,  1820,  p.  119.  ^J.  G.  Percival,  Kept.  Geol.  Conn.,  1842,  p.  233. 


42        GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

and  the  gneiss  then  extends  continuously  across  the  State  to  Northfield, 
where  it  is  partly  covered  by  newer  rocks  before  reaching  the  State  line. 
The  eastern  band  runs  north  to  Orange,  where  it  disappears  completely 
within  the  limits  of  Massachusetts. 

On  returning  to  the  study  of  the  Monson  gneisses,  after  long  experience 
with  the  change  of  the  Cambrian  conglomerates  into  the  white  gneisses  in 
the  Berkshire  Hills,  the  traces  of  the  same  change  struck  me  in  the  stretched 
gneisses  of  Monson  and  Pelham.  The  traces  of  pebbles  may  now  and  then 
be  clearly  seen,  and  I  present  a  reproduction  of  a  photograph  of  the  north- 
east corner  of  Walker  Hall,  one  of  the  buildings  of  Amherst  College,  which 
shows  this  clearly  (PI.  I,  p.  64).  The  rock  is  from  Monson,  and  in  1890 
a  great  wall  of  conglomerate  was  exposed  in  the  quarry  just  north  of  the 
trap  dike,  but  it  was  all  quarried  away  in  1892.  In  many  cases  the  flat 
patches  of  lighter  color  and  of  long  elliptical  shape  which  appear  on  the 
cleaved  foliation  faces  of  the  gneiss  seem  to  be  the  remains  of  pebbles 
wholly  flattened  out  into  films,  as  was  suggested  by  President  Hitchcock 
in  his  remarkable  investigation  of  distorted  pebbles.^ 

THE    PELHAM    AND    WILBRAHAM    AREA. 

THE    GNEISS.    ' 

The  broad  anticline  of  this  area  enters  the  towns  of  Northfield  and 
Warwick  from  New  Hampshu-e,  and  though  its  surface  is  at  first  covered  in 
part  by  isolated  areas  of  newer  rocks,  it  soon  expands  to  a  greater  width 
than  any  other  gneiss  in  the  counties,  and  maintains  this  width  nearly  across 
the  State,  interrupted  by  the  protrusion  of  the  Belchertown  tonalite. 

It  is  in  Northfield  a  fine  quarry  stone,  especially  marked  on  foliation 
faces  by  small  squarish  blotches  of  jet-black  hornblende,  and  it  continues 
to  be  good  quarry  stone  in  large  part  clear  across  the  State.  It  differs 
curiously  from  the  other  areas  in  that  it  is,  across  the  central  portion  of  the 
State,  a  broad  anticline  with  all  its  central  portions  almost  horizontal  and 
at  the  edges  bending  down  quite  sharply  beneath  the  newer  rocks.  A 
further  distinction  of  this  area  is  found  in  the  presence  of  a  great  bed  of  an 
actinolite-quartzite,  which  will  be  S23ecially  described,  and  in  the  presence 
of  three  great  intrusions  of  an  olivine-enstatite  rock,  which,  with  its  complex 
contact  phenomena,  will  be  also  the  subject  of  a  separate  chapter. 

'  Geology  of  Vermont,  Vol.  I,  1861,  p.  28. 


THE  PELHAM  AND  WILBRAUAM  AREA.  43 

To  the  south  the  rock  is  coarser  than  in  the  other  areas,  and  in  contact 
with  the  great  mass  of  the  Belchertown  tonalite  is  considerably  altered. 

In  Wilbrahara  its  attitude  is  nearly  vertical,  and  it  forms  the  core  of  an 
anticline  which  is  slightly  overturned  to  the  east,  as  the  dips  are  high  to 
the  west. 

At  Power's  mine,  in  Greenwich,  on  the  high  hill  overlooking  the  house 
of  S.  B.  Estey,  considerable  blasting  has  been  done  upon  a  vein  of  coarsely 
granular  magnetite,  containing  much  coarse  red  garnet  and  pyrite — an 
entirely  worthless  deposit. 

PETROGRAPHICAi  DESCRIPTION. 

1.  Granitoid  gneiss  from  Massachusetts  Agricultural  College  quaiTy, 
Pelham.     This  may  be  taken  as  a  type  of  the  Monson  gneiss. 

A  very  clear,  fresh,  gray,  stretched  biotite-gneiss.  It  is  a  most  crisp 
and  friable  stone,  showing  no  trace  of  decomposition,  the  fresh  black  biotite 
appearing  in  the  mixture  of  limpid  quartz  and  feldspar. 

Titanite  is  an  abundant  constituent,  and  rarely  a  trace  of  epidote 
appears  in  the  neighborhood  of  the  biotite.  The  lens  shows  the  jet-black 
biotite  scattered  in  an  almost  limpid  granular  mass,  with  faint  trace  of 
porphyi'itic  structure  and  slight  nacreous  dusting.  Under  the  microscope 
the  quartz  shows  swarms  of  minute  inclusions,  with  groups  of  larger  cavities 
having  moving  bubbles.  One  grain  alone  was  filled  with  long  rutile  needles, 
and  this  had  a  slightly  reddish  shade. 

Orthoclase  occurs  in  larger  crystals  than  the  other  constituents  and 
includes  rounded  quartz  grains.     It  is  quite  abundant. 

Microcline  is  abundant  and  of  late  formation,  crystallized  out  so  as  to 
cement  a  great  number  of  quartz  grains. 

Albite  occurs  rarely. 

The  biotite  is  in  separate  black  scales,  and  with  the  lens  is  seen  to  be 
abundant,  much  notched  and  often  extended  to  include  several  quartz 
grains. 

Titanite  is  in  angular  grains  of  the  same  size  as  the  other  constituents, 
and  in  distinct  crystals,  pale  greenish-brown  exteriorly  and  deep  red- 
brown  in  the  interior,  the  boundary  between  the  two  colors  being  generally 
distinct,  but  in  one  case  a  red-brown  crystal  is  inclosed  by  a  pale-yellow 
one,  the  two  being  of  common  orientation  and  the  outer  bounded  by  fewer 
faces. 


44  GEOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 


Zircon  is  quite  regularly  disseminated  in  colorless  to  pale-yellow  crys- 
tals one-fiftli  to  one-tenth  tlie  size  of  the  other  constituents  and  regularly 
crystallized  in  stout  prisms,  some  almost  cubical.  The  forms  P,  2  P  2,  co  P  oo 
could  be  seen  in  one  crystal.     It  is  included  in  all  the  other  constituents. 

Magnetite  is  absent. 

2.  Biotite-giieiss  from  Bassett's  quaiTy,  Northfield. 

A  fine  quarry  gneiss,  light-gray.  On  the  foliation  faces  distant,  squar- 
ish, thin  plates  of  hornblende  make  the  rock  appear  as  if  ink-spattered.  The 
feldspar  appears  as  glassy  as  the  quartz,  which  is  common  in  all  these  gneisses, 
though  it  shows  traces  of  change  into  muscovite  under  the  microscope. 

There  are  present  orthoclase,  microcline,  and  albite;  a  fragment  of  the 
latter  gave  extinction  -f  15°  on  go  Poo  ,  and  the  tri clinic  feldspar  in  all  these 
gneisses  give  commonly  an  extinction  of  -+-4°  on  either  side  of  the  twinning 
sutures  on  0  P.     Fine  minute  zircons  are  present,  but  no  titanite. 

3.  Hornblende-gneiss  from  southwest  Shutesbury,  opposite  W.  Thresher's, 
adjoining  trap  dike.  It  is  a  sandy-granular  rock  of  very  fine  and  even 
grain,  and  of  very  dark-gray  color.  It  is  a  rock  quite  common  in  the  Monson 
gneiss,  and  found  also  in  the  Becket  gneiss,  in  the  northeast  of  Tolland.  It 
becomes  much  more  abundant  in  the  eastern  area,  in  its  southern  exten- 
sion into  Connecticut,  where  it  is  Percival's  C  3Mn  its  eastern  portion. 

Microscopical  character :  The  background  is  made  up  of  little  quartz, 
little  albite  (extinction  6°  on  either  side  twinning  lines),  and  much  limpid 
orthoclase,  without  cleavage,  and  determined  only  by  its  positive  biaxial 
character. 

The  abundant  hornblende  molds  and  incloses  the  other  constituents; 
it  shows  peculiar  basal  cleavage  in  fine,  close,  straight  lines.  Its  absorp- 
tion and  pleochroism  are  exceedingly  strong  jc>tr>a.  c=deep  blue ;  tt=deep 
olive;  a=bright  yellow;  much  deep-green  biotite  and  large  light-red  garnet, 
many  plates  of  tremolite,  miich  black  and  red  ore,  and  a  single  group  of 
leucoxene  grains. 

4.  Biotite- gneiss  from  east  foot  of  Mount  Hygeia,  upper  quarry.  A 
white  gneiss,  making  heavy  beds  above  the  normal  gneiss  of  Pelham,  dif- 
fering from  it  by  the  small  amount  of  black  biotite  in  distant  scales  and 
the  abundance  of  small  red  garnets. 

The  quartz  contains  no  rutile  needles,  and  is  in  rounded  grains  that 

'Eept.  Geol.  Conn.,  p.  222. 


THE  PELHAM  AND  WILBKAHAM  AKEA.  45 

suggest  water-wear.  These  are  cemented  by  newly  deposited  quartz  and 
feldspar.  It  contains  cavities,  which  are  often  negative  crystals  with  very 
large,  motionless  bubbles,  and  other  long  trains  of  cavities,  showing  in 
great  numbers  smaller  bubbles  in  rapid  motion,  not  affected  by  being 
heated  to  70°  C. 

Orthoclase  predominates.  Albite  and  microcline  are  present.  Biotite 
occurs  in  deep  brownish-green  scales.     There  is  little  muscovite. 

A  single  square  prism  of  deep-red  rutile  was  seen  in  the  slide. 

Zircons  are  rare.  Single  large  grains  of  menaccanite  were  seen, 
changing  to  leucoxene. 

THE   ACTINOLITBQUARTZITE. 

The  central  portion  of  the  Pelham  gneiss  area  presents  two  peculiari- 
ties as  compared  with  the  other  similar  areas,  viz,  the  series  of  olivine- 
enstatite  rocks  and  the  great  quartzite  beds  here  described. 

The  biotite  of  the  gneiss  disappears  at  a  certain  level  and  reappears 
again  as  suddenly,  leaving  a  great  bed,  perhaps  300  feet  thick,  between 
two  beds  of  the  Monson  gneiss  which  can  not  be  distinguished  from 
each  other.  The  intervening  quartzite  bed  varies  from  a  fine-grained 
quartzite  to  an  equally  fine-grained  quartz-feldspar  mass,  with  needles  of 
tremolite  or  pale  grass-green  actinolite,  just  visible  to  the  eye,  scattered 
through  the  mass.  It  becomes  at  times  a  more  distinctly  bedded  rock,  and 
almost  continuous  films  of  the  same  pale-green  actinolite  appear  on  the 
foliation  faces.  Small  garnets  are  quite  commonly  disseminated,  and  at 
times  distant,  minute  scales  of  an  amber  mica  replace  the  actinolite. 

Distribution. — The  outcrop  of  the  rock  is  quite  peculiar  and  depends 
upon  the  great  flatness  of  the  dome  of  the  gneiss  synchne  in  Pelham. 
The  bed  is  exposed  by  the  double  scalping  of  the  undulating  surface  of 
this  syncline,  and  appears,  therefore,  in  one  closed  ring  in  Shutesbury  and 
in  a  loop  open  to  the  south  in  Pelham. 

Beginning  in  the  northwest  corner  of  Belchertown,  it  runs  north  along 
the  eastern  slope  of  the  Pelham  range,  passing  just  east  of  Pelham  post- 
office  and  just  west  of  the  poor  farm,  and  continues  north  through  the 
center  of  Shutesbury  and  a  little  beyond  it;  then  it  turns  sharply  southwest, 
and  its  dip,  which  had  been  low  east,  becomes  westerly.  It  then  runs 
southwest  into  Pelham  again  and  ends  in  the  high  peak  of  Hygeia.     Its 


46        GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

extension  is  shifted  more  tliau  a  mile  eastward  to  the  waterworks  dam  by 
a  fault,  and  it  continues  from  this  point  southwardly,  passing-  east  of  the 
"asbestos  mine." 

'The  other  great  area  occupies  the  eastern  portion  of  Leverett,  is  cut  off 
on  the  north  by  a  fault  at  the  Rattlesnake  Grutter,  and  projects  southwardly 
across  Shutesbury  into  the  western  portion  of  Pelham,  where  it  ends  under 
Mount  Hygeia,  approaching  near  the  other  band. 

PETKOGRAPHICAL  DESCRIPTION. 

1.  Adinolite-tremolite-gneiss  from  Northfield,  east  of  R.  H.  Minot's,  and 
adjoining  the  great  north-south  fault.  A  greenish-gray,  stretched,  ligniform 
rock,  the  abundant  needles  just  visible  to  the  eye.  In  a  fresh,  granular 
quartz-orthoclase  base  the  abundant  parallel  needles  of  pale-green  actino- 
lite  and  tremolite  appear.  They  show  a  delicate,  close  prismatic  cleavage, 
distant,  strong  basal  parting,  and  strong  absorption  and  pleochroism.  Green 
and  brown  biotite  are  abundant,  and  there  is  much  magnetite. 

This  is  the  only  occurrence  of  the  rock  in  the  western  portion  of  the 
Pelham  area,  and  it  is  soon  cut  off  on  one  side  by  the  fault  and  on  the 
other  by  granite. 

2.  Micaceous  quartzite  from  Pratts  Comer,  southwest  Shutesbury.  In 
a  white,  fine-grained,  only  subgranular  quartz  mass  are  scattered  small, 
rounded,  red  scales  of  biotite.     No  feldspar. 

Under  the  microscope  the  quartz  mass  shows  only  rarely  a  fissure,  and 
is  so  homogeneous,  colorless,  and  free  from  foreign  bodies  that  it  is  invisible 
in  common  light.  "With  crossed  nicols  it  shows  a  most  complex  mosaic  of 
interlaced  grains 

The  red  scales  of  biotite  are  all  in  parallel  planes,  and  inclose  zircons 
which  are  surrounded  by  a  marked  deep-brown  pleochroic  border.  The 
zircons  are  also  scattered  through  the  quartz  in  fine  crystals.  Red-brown, 
stout  rutile  prisms  occur  surrounded  by  a  granular,  colorless  leucosene. 

3.  Actinolite-qtiartsite  from  north  side  of  brook  and  about  100  feet  east 
of  the  dam  of  the  Amherst  waterworks  in  Pelham.  To  the  eye  the  rock 
is  like  a  fine-grained,  white  sandstone  or  crisp,  friable  quartzite,  with  scat- 
tered needles  of  pale-green  to  almost  colorless  actinolite.  The  lens  rarely 
detects  a  grain  of  feldspar.  It  is  whiter  and  contains  less  actinolite  than 
the    Mount    Hygeia  rock,  but  is  closely  like   it.     Under   the  microscope 


THE  PELHAM  AND  WILBRAHAM  AREA.  47 

the  fresh  o-ranular  quartz  is  free  from  fluid  pores  and  acicular  microlites. 
Feldspar  is  uot  distiuguishable. 

The  nearly  colorless  actiuolites  are  parallel,  and  contain  large,  rounded 
grains,  common  also  in  the  quartz,  which  are  strongly  refringent  and  polarize 
brilliantly;  they  may  be  zircon.  Other  grains  clustered  along  the  actinolite 
crystals  seem  to  be  epidote. 

4.  ActinoUte-quartzite  from  east  bluff  of  Mount  Hygeia,  Pelham.  A 
granular  quartz,  white  and  of  medium  grain,  with  parallel  needles  of  color- 
less to  aquamarine  actinolite. 

In  the  granular  quartz  ground  the  actinolite  needles  are  irregularly 
arranged;  here  and  there  is  a  scale  of  biotite.  There  are  large  zircons  and 
microlites  inclosed  in  quartz  and  actinolite ;  also  grains  of  titanite. 

SAXONITE   AND   SERPENTINE   IN  MONSON   GNEISS. 
THE  PELHAM  ASBESTOS  QUARRY. 

This  locality  has  been  long  known  as  furnishing  large  masses  of  a 
hard  asbestos,  and  the  mineral  has  been  extensively  quarried. 

Its  interest  from  a  mineralogical  point  of  view  was  greatly  increased 
by  the  discovery  in  1869,  by  Mr.  A.  B.  Kittredge,  of  corundum  in  hard 
nodules  in  the  biotite,  which  occurs  there  in  great  abundance.  Later,  Pro- 
fessor Shepard,  observing  the  difficult  fusibility  of  the  "asbestos,"  analyzed 
it  and  found  it  to  have  the  composition  of  bronzite,  but  gave  it  the  wholly 
superfluous  name  asbestite.  He  also  analyzed  a  tough,  black,  granular 
mineral  which  occurs  in  large  masses  in  the  deeper  parts  of  the  several 
excavations  and  found  it  to  have  the  composition  of  oli^dne,  but  named  it 
pelhamine,  a  name  equally  supei-fluous,  as  the  mineral  is  optically  as  well 
as  chemically  identical  with  olivine,  and  its  black  color  is  due  to  dissemi- 
nated magnetite  and  chromite. 

The  pits  by  which  the  bed  is  exposed  are  scattered  for  a  distance  along 
an  eastward-sloping  hillside,  and  as  the  dip  is  40°  W.,  while  the  strike  of 
the  inclosing  Monson  gneiss  is  due  north,  the  lenticular  mass  is  exposed 
by  erosion  in  a  plane  at  right  angles  to  its  dip,  giving  a  length  of  about  200 
feet  and  a  greatest  thickness  of  40  feet. 

This  is  a  great  lens  or  short  dike — probably  an  old  volcanic  core — of 
the  highly  basic  igneous  rock  saxonite,  in  the  highly  acid  conglomerate 


48 


GEOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 


gneiss;  and  during  the  strong  metamorphism  which  has  transformed  the 
conglomerate  into  a  gneiss,  the  saxonite  has  been  largely  changed  into 
anthophyllite,  and,  what  is  of  higher  interest,  a  broad  selvage — a  "reaction 
rim "  on  a  grand  scale — has  formed  by  the  mutual  influence  of  the  basic 
core  and  the  acid  surrounding.  This  selvage  consists  largely  of  minerals 
containing  little  or  no  silica — apatite,  corundum,  magnetite,  tourmaline, 
anorthite,  and  biotite.  It  wraps  around  the  saxonite  with  great  irregularity, 
often  folding  deeply  into  its  mass. 

Measured  downward  from  the  hanging  wall,  the  mass  is  greatly  decom- 
posed for  a  depth  of  from  3  to  12  feet,  and  as  the  pits  have  been  sunk  in 
this  decomposed  portion  and  work  stopped  as  the  hard  unaltered  rock  was 


'^^^±¥*€rt^*"''^^^^^ 


8  FT 


Fig.  3.— Southwest  wall  of  Pelham  asbestos  quarry  in  1890.  A,  Pelham  gneiss;  B,  anorthite  rook;  C,  black 
tourmaline  masses ;  D,  biotite  layer ;  D',  vermiculite  layer  (Termiculite  and  steatite  from  biotite  and  actinolite) ;  B,  saxonite ; 
F,  anthophyllite  derived  from  saxonite. 

approached,  attention  has  been  directed  almost  entirely  to  this  decomposed 
portion,  which  will  be  discussed  a  little  later.  The  pits  everywhere 
disclose  at  the  bottom  the  black  rock,  which  consists  of  granular  olivine, 
chromite,  magnetite,  and  bronzite  (saxonite),  without  admixture  of  any 
other  minerals,  and  of  this  rock  the  whole  intruded  mass  originally 
consisted. 

At  the  top  of  the  wall  in  the  large  central  cutting  the  contact  of  the 
superincumbent  gneiss  upon  the  olivine  rock  can  be  well  studied,  and  it  is 
very  peculiar.  (Fig.  3.)  The  gneiss  penetrates  the  olivine  rock  in  a  great 
club-shaped  apophysis,  the  lamination  of  the  gneiss  being  first  bent  down 


THE  PELHAM  AND  WILBKAHAM  AREA. 


49 


toward  rlu'  latter  iuul  then  somewhat  confused,  but  distinctly  traceable  far 
iiUi)  it  and  dyiui;-  oTit  gradually  by  the  slow  disappearance  of  the  biotite 
and  ([uartz,  until  the  whole  of  the  great  projection  is  made  up  of  a  mass  of 
snow-white,  extremely  fine-granular,  massive  anorthite,  carrying  toward  its 
borders  a  large  quantity  of  black  tourmaline  in  great  irregular  bunches, 
which,  at  the  apex  of  the  mass,  afi'ords  blocks  of  pure,  coarsely  crystalline 
tourmaline  over  2  feet  across.  The  fluorine  of  the  biotite  has  gone  into 
the  tourmaline.  Many  small  crystals  of  allanite  are  shot  through  the 
anorthite,  and  when  broken  across  the  latter  mineral  shows  the  usual 
puckered  surface  radiating  from  the  allanite. 


■-  ■•■;> 


8  FEET 


FiS.  4.— "West  wall  of  Pelham  asliestoa  quarry=rigbt  half  of  fig.  3,  qnarried  deeper.    Letters  as  in  flg.  3.    G,  cortmdiim 

nodules;  H,  apatite. 

The  tourmaline  breaks  into  large  imperfect  crystals,  often  8  to  12 
inches  long,  and  in  cavities  shows  terminations  always  Avith  broad  0  P 
planes.  It  contains,  in  cavities  between  crystals,  zoisite,  apatite,  and  beau- 
tiful geniculate  twins  of  rutile,  together  with  perfect  apatites  alone  in  other 
cavities  and  in  the  mass  itself.  Under  the  microsco^ie  it  often  shows  an 
exquisite  micropegmatitic  intergrowth  with  the  anorthite,  the  latter  taking 
the  place  of  the  quartz  in  graphic  granite,  while  the  tourmaline  is  extin- 

MON  XXIX 4 


50        GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

guished  as  a  single  individual  over  broad  surfaces  and  in  large  disconnected 
reticulate  portions.  At  the  line  of  contact  of  the  tourmaline  and  the 
anorthite  many  microscopic  deep-red  rutiles  occur. 

This  anorthite  projection,  which  is  a  thickened  part  of  the  outer  layer 
of  the  "reaction  I'im,"  is  separated  from  the  olivine  rock  by  a  thick  band  of 
a  deep  bronze-colored  biotite  in  large  scales,  which  is  wrapped  around 
and  extends  beyond  this  projection.  As  it  separates  the  gneiss  at  the 
north  end  of  the  bed  from  the  olivine  rock,  it  may  very  probably  be  a  con- 
tinuous layer  around  the  latter.     Nothing  can  be  seen  of  the  lower  contact. 

This  biotite  band,  usually  4  to  8  inches  thick,  reaches  in  places  a  thick- 
ness of  nearly  4  feet,  and  incloses  hard  nodules  of  a  blackish-green  matted 
hornblende  and  of  the  finest  emerald-green  parallel-fibered  actinolite,  and 
other  similar  nodules  which  contain  large,  imperfect  crystals  of  gray 
corundum  with  central  spots  and  streaks  of  rich  sapphire-blue  (see  fig.  4), 
which  are  wrapped  in  a  greenish  chloritic  mineral  of  large  axial  angle 
and  marked  pleochroism,  probably  clinochlore.  Still  other  nodules  contain 
large  friable  masses  of  a  fine  grass-green  actinolite. 

It  is  interesting  to  note  how  the  extremely  basic  character  of  the  olivine 
rock  is  continued  outward  in  the  biotite-corundum  rock  and  beyond  in  the 
anorthite-tourmaline  rock,  and  to  observe  how  uniform  this  collocation  of 
minerals  is  in  all  parts  of  the  world — a  subject  to  which  I  recur  after  describ- 
ing the  Chester  emery  bed  (Chapter  VI). 

The  broad  border  of  decomposition  products  of  the  olivine  rock  men- 
tioned above  is  of  the  highest  interest,  and  for  its  understanding  reference 
may  be  made  to  the  accompanying  fig.  3  (p.  48).  Between  the  biotite  (d) 
and  the  unchanged  olivine  (e)  is  a  layer,  generally  about  3  feet  thick, 
which,  nearer  the  outcrop  (at  the  left  of  the  figure),  is  13  feet  thick,  and 
consists  of  olivine  changed  in  part  to  a  pale-yellow,  friable,  granular 
villarsite,  and  in  part  to  an  earthy  mass  of  ochery  appearance.  Through 
this  runs  an  irregularly  anastomosing  network  of  veins  of  fibrous  antho- 
phyllite  (f),  which  reach  at  times  a  thickness  of  8  inches,  at  times  run 
out  to  extreme  thinness  and  disappear.  They  are  for  the  most  part  made 
up  of  a  woody  mass  of  fibers,  which  are  placed  at  right  angles  to  the 
walls  of  the  vein  and  meet  on  a  suture  at  the  center.  In  the  thicker 
veins  the  visibly  fibrous  poi'tion  exists  only  a  few  inches  fi-om  the  walls 
on  either  side,  and  the  central  portion  is  made  up  of  a  compact,  woody 


THE  PELIIAM  AND  WILBRAHAM  AREA.  51 

mass,  splittiiiji'  in  ;i  direction  at  right  angles  to  the  walls,  and  pearl-gray 
when  not  blackened  by  manganese. 

More  rarely  the  vein  filling  is  completely  asbestiform  and  the  fibers 
cross  the  vein  from  side  to  side;  very  often  they  are  all  bent  somewhat  to 
one  side  or  the  other  as  they  approach  the  wall,  being  compressed  by  their 
own  growth. 

In  other  parts  of  the  excavation  these  veins  have  swollen  to  much 
greater  width,  and  great  ligniform  masses,  20  to  30  inches  in  length,  have 
been  excavated.  This  is  the  "asbestos"  of  the  quarry,  and  many  hundred 
tons  have  been  excavated  and  sold  for  grinding  into  paint  and  for  asbestos 
papers.  The  resemblance  of  this  structure  to  the  well-known  microscopic 
olivine  network  is  extremely  striking,  and  it  would  seem  difficult  to  avoid 
the  conclusion  that  the  anthophyllite  here  must  be  of  secondary  oi-igin  and 
a  derivative  from  the  olivine,  probably  under  conditions  of  considerable 
pressure  and  heat,  and  therefore  at  an  early  period  in  the  history  of  the 
changes  which  the  deposit  has  undergone.  Its  exact  resemblance  to  the 
transverse  fibrous  vein  fillings  of  calcite,  gypsum,  and  chrysotile  will  hardly 
admit  for  it  any  essentially  different  explanation. 

The  anthophyllite  occurs  also  in  large,  rather  coarse-matted  fibers.  It 
polarizes  very  brilliantly  and  is  quite  fresh  and  limpid,  the  gray  color  being 
due  to  fine  magnetite  dust. 

At  the  northern  excavation  and  at  the  large  opening  there  are  sparingly 
disseminated  in  the  fresh  oUvine  rock  squarish  plates,  J  to  ^  inch  across,  of  a 
pale  bronzy  enstatite  or  bronzite,  making  an  ordinary  olivine-enstatite  rock. 
This  is  a  primary  bronzite. 

Masses  of  a  bright  emerald-green  actinolite  in  matted  fibrous  arrange- 
ment of  the  single  crystals  were  produced  from  the  large  opening,  but 
their  relations  to  the  other  minerals  can  not  now  be  observed.  At  a  new 
excavation  made  during  the  year  1883,  near  the  south  end  of  the  bed, 
a  long  band  of  this  mineral  was  struck  just  below  the  drift,  and  resting 
upon  the  thick  decomposition  layer  of  anthophyllite,  in  the  midst  of  which 
several  thin  layers  of  the  actinolite  also  appeared. 

The  biotite  containing  nodules  of  the  dark-green  hornblende  here  also 
folded  deep  into  the  saxonite,  as  at  the  large  cutting.  The  anthophyllite 
layer  was  followed  in  the  bottom  of  the  excavation  by  the  usual  black, 
undecomposed  olivine  rock.     The  biotite  has  also  been  attacked  on  a  large 


52  GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

scale  by  a  decomposition  which  has  resulted  in  the  fonnatiou  of  a  mass  of 
soft,  greasy  scales  of  vermiculite  (D'  fig.  4),  which,  when  boiled  with  sul- 
phuric acid,  yields  a  residue  of  white  scales  of  pure  silica.  This  has  been 
named  pelhamite  by  Prof  J.  P.  Cooke,  and  thus  the  town  of  Pelham  has 
lent  its  name  to  two  equally  poor  minerals. 


PETROGEAPBICAL   DESCRIPTION. 


1.  Saxonite,  or  olivine-enstatite  rock  (pelhamine,  Shepard).  This  is  a  very 
fresh  mixture  of  olivine  and  enstatite,  both  dusted  thi-ough  with  black  ore, 
largely  chromite.  It  is  a  dull-black  rock  of  very  great  toughness.  The 
olivine  grains  have  often  many  crystalline  faces.  The  enstatite  is  in  rare, 
small  plates,  with  parallel  sides  and  ii'regular  ends,  and  with  a  fine  wavy 
lamination,  which  is  often  marked  by  lines  of  black  ore  generally  concen- 
trated in  some  part  of  the  plate,  especially  the  center.  Although  neai'ly 
colorless  or  pale  bronzy  in  common  light,  it  has  marked  pleochroism.  It  is 
plainly  rhombic,  and  grades  into  the  asbestiform  decomposition  product  in 
veins  running  tlu-ough  the  section.  The  distant,  strongly  marked  transverse 
cleavage  so  common  in  enstatite  is  wanting. 

2.  Secondary  asbestiform  anthopliyllite  occurs  in  the  altered  saxonite  in 
clear  gray  masses  parallel  or  matted  fibrous,  in  the  former  case  so  fine- 
grained as  to  resemble  silicified  wood,  in  the  latter  made  up  of  a  mass  of 
short  needles  without  radiated  structure.  It  has  very  harsh  feel.  With  a 
lens  it  seems  to  be  entirely  fresh,  transparent,  and  colorless,  the  gra}?-  color 
being  due  to  disseminated  magnetite,  which  is  visible,  and  may  be  removed 
fi'om  the  powder  by  a  magnet. 

Under  the  microscope  it  presents  a  mass  of  colorless  needles  and  blades 
with  delicate  longitudinal  striation,  which  breaks  off  here  and  there  against 
a  transverse  cleavage.  The  needles  are  broken  across  by  a  distant  fracture 
not  exactly  at  right  angles  to  the  length.  Long,  fine,  straight  needles, 
breaking  up  at  times  into  a  row  of  grains,  are  present,  and  thoixgh  not  very 
abundant,  are  concentrated  more  in  the  center;  they  appear  black,  but  at 
times  red  with  high  powers.  In  crystals  cut  across  the  blades  the  form  and 
cleavage  of  hornblende  can  be  detected,  and  I  was  able  to  separate  and 
measure  one  needle,  obtaining  55.30°.  They  polarize  brilliantly,  and  always 
strictly  as  rhombic  crystals,  and  this  is  the  case  with  the  silky  asbestos. 

3.  The  ]}lagioclase-feldspars  of  the  contact  zone.  Professor  Shepard 
analyzed  the  two  varieties  of  massive  triclinic  feldspar  found  in  the  great 


THE   I'ELIIAM  AND  WILBEAHAM  AREA.  53 

apopliysis  ])cuetratinj>'  tlie  saxonite:  (a)  tlm  white  saccliavoidal  portion 
ibrining-  its  extremity  and  nearest  to  the  oHvine;  (h)  the  Ijhiish-white,  coarser- 
grained  portion  which  formed  the  neck  of  the  mass  and  passed  into  the  gneiss. 
For  the  former  he  fonnd  the  composition  of  anorthite,  and  for  the  Litter 
that  of  andesite.  The  Litter  portion,  as  it  approaches  the  common  gneiss,  is 
less  pnre  than  the  other,  containing  much  biotite,  but  with  the  microscojje 
the  characters  of  anorthite  were  presented  clearly  by  both  varieties;  here 
and  there,  however,  the  larger  crystals  were  very  distinct  and  were  clearly 
andesite.  The  mass  is  like  the  feldspar  accompanying  the  "fringe  rock" 
of  the  Chester  emery  bed. 

The  portion  called  andesite  by  Shepard  is  compact  to  fine-granular, 
translucent,  bluish-white,  fresh-looking,  showing  slight  flesh  color  from  the 
abundance  of  small  disseminated  biotite  crystals,  and  having  seams  and 
irregular  masses  of  black  tourmaline  scattered  through  it.  Occurring 
largely  in  the  latter,  and  more  sparingly  disseminated  in  the  feldspar,  are 
minute  crystals  of  zircon: 

The  anorthite  grains  are  often  almost  entirely  single  individuals;  here 
and  there  a  few  very  fine  distant  twin  laminae  are  interposed,  but  these 
run  out  in  a  short  distance,  and  in  many  cases  the  whole  surface  is  covered 
by  distant  laminge  lying  at  right  angles  to  each  other.  The  maximum 
extinction  was  31°  to  34°. 

Under  the  microscope  the  feldspar  shows  through  a  lacelike  network 
of  brightly  polarizing  films  or  raveled-out  scales  of  muscovite,  and  this 
increases  until  in  slides  cut  from  seemingly  quite  fresh  material  the  feld- 
spar can  scarcely  be  distinguished  in  the  mat  of  mica  scales. 

The  biotite  is  optically  uniaxial,  and  is  often  decomposed  wholly  or  in 
part,  the  sides  being  dissolved  into  a  congeries  of  colorless  scales,  or  the 
change  attacking  one  or  several  of  the  laminae  and  proceeding  quite  across 
the  specimen;  and  much  of  the  new  mineral  has  wandered  out  and  surrounds 
the  biotite  crystals  in  large  spots,  which,  with  reflected  light,  are  seen  to 
surround  the  remnant  of  the  original  crystal  like  a  growth  of  glistening 
white  mold,  and  these  white  spots  are  visible  to  the  eye  all  over  the  slide. 

The  zircons  are  white,  with  a  faint  tinge  of  red  and  a  high  adamantine 
luster,  or  deep  amber  color  to  pale  red  by  reflected  and  reddish  olive-green 
by  transmitted  light.  The  white  crystals  are  most  regularly-formed,  long, 
square  prisms  with  sharp  termination  P  and  3  P,  and  apparently  3P  3.     The 


54        GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

red  crystals  show  at  times  a  sharp  prismatic  cleavage,  being  often  very 
irregular  lobed  masses  and  often  very  regular  crystals  with  shining  faces. 

The  andesite  (Shepard's  type)  crystals  are  about  20  by  10  by  10"™, 
not  bounded  by  distinct  faces,  but  embedded  in  a  granular,  compact  mass 
of  anorthite,  translucent  and  bluish- white,  with  many  small  scales  of  biotite 
intermixed.  Sections  cut  parallel  to  0  P,  go  P  &,  and  oo  P  oo  were  much 
decomposed  and  impregnated  with  scales  of  muscovite,  placed  principally 
in  the  planes  of  principal  cleavage  and  in  especially  large  plates  parallel 
to  00  P  do.  It  is  poly  synthetically  twinned  parallel  to  oo  P  do  in  broad 
continuous  plates  of  equal  width;  extinction  on  co  P  do,  — 13°  to— 14°; 
on  OP,  — 4°  to  — 5°,  agi-eeing  thus  exactly  with  andesite 

4.  Serpentine  from  Pelham,  about  100  yards  west  of  the  "asbestos'' 
mine.  Dull  black-green  serpentine,  changed  an  inch  deep  into  white  talc 
and  showing  deep  in  the  interior  "ph8estine"-like  aggregations  of  talc,  from 
alteration  of  the  bronzite. 

Slides  cut — (a)  from  the  outer  talc  layer,  (6)  from  the  layer  of  transi- 
tion, (c)  from  the  interior  deep-green  serpentine — showed: 

(a)  A  mass  of  wavy  talc  scales  containing  remains  of  bronzite,  with 
long  jet-black  hairs,  slightly  curved,  placed  parallel  to  the  vertical  axis  of 
the  bronzite  and  ending  on  the  mass  of  talc  scales  into  which  the  mineral 
is  decomposed;  (V)  a  matted  mass  of  actinolite  fibers  of  pale-green  color, 
very  strongly  dichroic;  (c)  a  mass  of  actinolite  fibers  and  talc  scales,  with 
small  portions  of  serpentine  and  in  places  with  grains  showing  the  olivine 
network,  the  whole  having  the  outward  aspect  of  a  common  serpentine. 

The  specimens  labeled  "Black  serpentine  and  talc,  Pelham,  Mass.," 
No.  132,  in  the  Massachusetts  State  Survey  collection  of  President  Hitch- 
cock, is  from  the  above  locality. 

5.  Epidote-gneiss  from  Pelham;  asbestos  quarry.  An  even,  fine-  or 
medium-grained  mixture  of  flesh-colored  orthoclase,  gray  quartz,  and  bright 
pistachio-green  biotite,  with  small  black  grains  of  tourmaline. 

Under  the  microscope  the  epidote  is  scattered  in  long  crystals  exactly 
like  the  plagioclase  in  a  diabase.  Minute  veins  are  entirely  filled  with 
epidote;  only  orthoclase  is  present  as  a  feldspathic  constituent,  and  around 
nuclei  of  this  broad  bands  of  epidote  needles  are  arranged  parallel  to  the 
former  cleavage  planes  or  outlines  of  the  feldspar,  showing  the  nucleus  to 
be  only  a  remnant  of  a  larger  crystal. 


THE  PELHAM  AND  WILBKAHAM  AREA.  55 

TIIK    rm.EIAM   SERPENTINE. 

About  325  feet  west  of  the  asbestos  mine,  on  a  small  flat  which  inter- 
rupts the  western  slope  of  the  hill  on  the  eastern  side  of  which  the  mine  is 
situated,  a  great  boss  of  serpentine  rises  through  the  till,  and  a  little  south  of 
it  a  second,  of  which  it  can  only  be  said  that  they  occur  within  the  limits  of 
the  Monson  gneiss.  The  rock  is  a  deep  dull-green,  opaque  when  wet,  and 
containing  chromite  in  some  abundance.  Over  a  large  portion  of  its  surface 
it  is  changed  for  some  distance  inward  into  a  white  talc,  and  as  this  change 
follows  the  surface  of  the  rock  it  is  plainly  a  change  of  the  serpentine  into 
talc  since  the  erosion  of  the  Glacial  period. 

THIS   SHUTESBUKY   SERPENTINE. 

A  second  locality  identical  with  the  "asbestos"  mine  in  Pelham  occurs 
a  mile  south  of  the  village  of  Shutesbury,  in  a  pasture  south  of  the  house 
of  C.  Leonard.  Fragments,  some  of  large  size,  lie  over  the  surface  in  a 
space  a  few  yards  square,  turned  up  by  plowing.  One  large  mass  of 
rusty-brown,  half-decomposed  olivine  rock,  shot  through  by  white  anthophyl- 
lite  fibers  and  full  of  chi-omite,  is  not  to  be  distinguished  from  similar 
masses  at  the  Pelham  locality.  The  fibrous  asbestiform  and  woody  varieties 
of  anthophyllite  are  repeated  here  also,  and  masses  of  a  green  chloritic 
mineral  occur.  The  dej^osit  is  surrounded  on  all  sides  by  outcrops  of  the 
Monson  gneiss,  but  its  exact  relation  and  size  can  not  be  determined. 

THE   NEW   SALEM   SERPENTINE. 

This  locality  is  situated  on  the  west  slope  of  Rattlesnake  Hill,  about 
300  yards  northeast  of  A.  A.  Haskell's  house.  The  country  rock  is  a  rather 
coarse  biotite-granitoid  gneiss,  striking  north-south  and  dipping  90°.  The 
old  digging  is  covered,  and  no  contacts  can  be  seen.  The  olivine  rock  is 
at  most  50  feet  wide  and  may  be  150  feet  long.  The  nearest  outcrops  of 
the  gneiss  are  wholly  normal  and  do  not  betray  the  presence  of  the  foreign 
body.  This  is  apparently  a  lenticular  mass,  its  greatest  diameter  coinciding 
Avith  the  strike.  The  greater  portion  of  the  rock  taken  out  is  deep  dull- 
black  olivine,  with  small  glistening  scales  of  a  micaceous  mineral,  appar- 
ently clinochlore.  The  rock  weathers  to  a  pale  isabella-yellow  from  the 
removal  of  the  black  ore  and  the  hydration  of  the  olivine.  Associated 
with  it  in  some  quantity  is  a  fine  fibrous  light-gray  anthophyllite,  largely 
altered  to  an  imperfect  steatite.     I  was  guided  to  the  spot  by  an  aged  man 


56        GEOLOGY  OP  OLD  HAMPSHIKE  COUNTY,  MASS. 

who  had  owned  the  land  for  more  than  half  a  century,  and  I  asked  him  how 
the  rock  had  been  discovered  in  the  thick  woods.  He  told  me  that  when  he 
was  a  small  boy  his  father  had  cleared  the  hillside,  a  desolate  slope  consist- 
ing largely  of  uncovered  ledges,  and  his  older  brother,  while  harrowing  in 
oats  on  the  spot,  noticed  that  the  harrow  teeth  made  no  noise  over  one  por- 
tion of  the  ledge,  but  gouged  deeply  into  the  rock.  He  thereupon  took  a 
large  piece  of  the  rock  home  and  put  it  into  the  fire,  but  could  not  melt  it. 
His  pyrognostic  experiments  do  not  seem  to  have  proceeded  much  further, 
but  long  after,  abovit  thirty-five  years  ago,  the  owners  dug  a  deep  trench 
into  the  mass,  dumping  a  great  quantity  over  the  bluff,  but  did  not  find 
anything  of  value  for  use  -as  soapstone,  only  a  small  portion  of  the  rock 
having  completed  the  change  to  steatite. 

THE  ORANGE  AND  MONSON  AREA. 

This  band  of  gneiss  extends  nearly  across  the  State  as  a  naiTow  anti- 
cline, and  near  its  north  line  in  Orange  the  axis  of  the  anticline  dips  down 
northwardly  beneath  the  fibrolite-schists.  Because  it  yields  more  readily 
to  erosion,  the  gneiss  occupies  the  bottom  of  a  deep  amphitheater  open  to 
the  south,  its  bottom  deepest  outwardly,  just  at  the  foot  of  the  sharp,  higli 
schist  hills  beneath  which  it  sinks.  At  its  northern  end  the  gneiss  is  quite 
granitoid  and  much  disturbed  by  small  intrusions  of  pegmatite.  Around 
Orange  village  it  is  a  fine  quarry  stone.  Much  of  it  is  a  dark  biotite-horn- 
blende-gneiss,  much  a  lighter  gneiss  containing  angular  fragments  of  the 
darker  variety,  and  very  tortuous. 

At  the  railroad  east  of  Orange  village  the  light-colored  granitic  gneiss 
folds  around  great  fragments,  or  groups  of  fragments,  of  the  dark  hornblende- 
gneiss,  which  have  been  but  slightly  moved  and  cemented  by  the  lighter 
o-neiss.  In  this  it  resembles  the  Shelburne  Falls  gneiss.  Two  east-west 
faults,  17  feet  apart,  here  include  a  much  darker  and  more  hornblendic 
o-neiss.  It  contains  prehnite  and  stilbite  in  fissures.  All  down  its  western 
border  in  Orange  its  contact  with  the  schists  above  is  more  like  that  of  an 
eruptive  with  an  overlying  sedimentary  than  like  that  between  two  sedi- 
mentary beds.  At  L.  Mayo's  it  is  very  granitic  and  is  intermixed  with 
the  lower  schists  in  a  confused  way.  In  the  village  of  Orange,  between 
Main  and  High  streets,  it  is  in  direct  contact  with  the  hornblende -schist, 
and  it  continues  in  contact  with  the  schist  across  into  New  Salem.     In  this 


THE  ORANGE  AND  MONSON  AliEA.  57 

town  au<l  jK-ross  Greeuwicli  aiul  Kutield — that  i«,  tor  20  iniles  soutla — it 
forms  the  bottom  of  a  very  peculiar,  deep  valley,  in  the'  center  of  which 
rise  strange,  isolated  peaks  which  have  in  some  unexjjlained  way  escaped 
the  general  erosion. 

Continuing  south  across  Ware  and  Palmer,  the  gneiss  band  narrows 
somewhat  and  the  valley  is  interrupted,  though  this  is  in  part  only  apparent, 
being  due  to  the  filling  of  the  valley  by  the  abundant  glacial-lake  deposits 
in  this  latitude.  Farther  south  the  valley  reestablishes  itself  in  Monson 
and  continues  far  beyond  the  limits  of  the  map  (PI.  XXX]  V). 

Across  Orange  the  newer  rocks  dip  toward  the  gneiss  from  all  sides, 
forming  a  fan  structure.  Across  the  remaining  area  it  forms  the  center  of 
a  closely  appressed  anticline,  slightly  overturned  to  the  east,  as  the  dips  are 
all  70°-80°  W. 

GENERAL   DESCRIPTION. 

The  Monson  gneiss  is  a  clear-gray,  friable  biotite-gneiss,  in  mass  made 
up  of  small  angular  grains  of  quartz  and  orthoclase,  equally  limpid  and 
colorless,  and  so  loosely  joined  that  there  are  many  interstices,  and  one  can 
sometimes  rub  a  fragment  into  powder  between  the  fingers.  Scattered 
through  this  aggregate  are  grains  of  shining  black  mica,  Avhose  parallel 
arrangement  produces  the  more  or  less  clearly  marked  foliation  visible  upon 
cross  fracture  and  the  equally  marked  "stretching"  seen  upon  the  foliation 
face.  The  foliation  is  produced  by  the  concentration  of  the  black  biotite 
in  bands  which  have  between  them  long  linear  or  elliptical  spaces  that 
appear  white  upon  the  gray  ground,  and  in  which  the  knots  of  feldspar 
mostly  occur  when  the  rock  becomes  subporphyritic.  The  stretching  is 
manifested  upon  the  foliation  faces  by  the  greater  concentration  of  the 
biotite  along  broad,  imperfectly  marked  parallel  bands;  and  oftentimes 
when  by  incipient  decomposition  the  feldspar  has  been  rendered  opaque 
white  or  flesh-colored  it  is  seen  to  have  the  same  linear  parallel  arrange- 
ment. This  structure  often  obtrudes  itself  more  readily  upon  the  attention 
than  the  foliation  itself  There  is,  however,  little  or  no  greater  tendency  in 
the  quarry  slabs  to  split  parallel  to  this  structural  feature,  and  blocks  are 
frequently  gotten  out  with  the  "stretching"  running  diagonally  across  their 
broad  faces. 

The  biotite,  although  so  important  for  the  color  and  structure  of  the 
rock,  is  present  in  rather  inconsiderable  amount. 


58  GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

There  are  also  here  and  there  in  the  mass,  and  especially  upon  the 
foliation  faces,  squarish  spots  of  a  black  hornblende,  generally  from  half  an 
inch  to  an  inch  across,  but  at  times  forming  great  lustrous  masses  larger 
than  one's  fist,  and  in  other  places  concentrating  in  distinct  strata — often 
accompanied  by  a  trace  of  copper — to  so  great  an  extent  as  to  form  a  black 
hornblendic  gneiss,  as  in  the  western  side  of  the  Monson  quarry  and  for  a 
long  distance  north  and  south.  This  bed  does  not,  however,  so  differentiate 
itself  from  the  remainder  of  the  gneiss  that  I  thought  it  desirable  to  separate 
it  upon  the  map. 

Titanite  is  a  very  generally  distributed  constituent  of  the  rock,  in 
honey-  to  straw-yellow  crystals,  flat,  often  well  formed,  and  reaching  a 
size  of  from  2  to  5""™. 

Pistachio-  to  oil-green  epidote  in  grains  is  aggregated  with  the  biotite, 
and  especially  with  the  hornblende,  making  a  loose  border  to  the  squarish 
plates  of  the  latter.  Garnet  and  magnetite  occur  in  small  grains.  A  pale- 
green  pyroxene  appears  rarely  in  large,  stout  prisms  embedded  in  the  rock. 

The  narrow,  white  interrupted  planes  which  express  the  foliation  are 
structure  planes  and  not  planes  of  separation  of  the  rock,  and  the  latter 
planes  are  at  times  so  closely  approached  as  to  divide  the  rock  into  thin 
plates  (about  4  inches  thick),  whereby  it  becomes  "scaly"  (the  local 
quarrymen's  term)  and  useless  as  a  building  stone.  In  other  places  the 
latter  planes  separate  more  widely,  furnishing  thick  banks  of  excellent 
quarry  stone.  The  blotching  with  hornblende,  or  with  large  roundish 
masses  of  white  feldspar,  and  the  amount  and  parallel  arrangement  of  the 
biotite  may  vary  in  all  these  structural  varieties,  forming  two  types  of 
special  importance.  On  the  one  side,  by  the  great  increase  of  the  feldspar 
nodules,  a  strongly  marked  "augen-gneiss"  is  formed,  which  is  the  "sub- 
porphyritic"  gneiss  of  Percival,^  the  "glandulous  gneiss"  of  E.  Hitchcock,^ 
and  which  differs  decidedly  from  the  porphyritic  gneissoid  granite  of 
Worcester  County,  for  that  is  a  complete  granite  with  porphyritic  carlsbad 
twins,  while  here  the  feldspar  is  in  rovmdish  masses  with  no  approach  to 
crystallographic  outline  and  not  twinned.  On  the  .other  hand,  by  the 
sinking  of  all  the  constituents  to  the  same  size  and  by  the  more  uniform 
arrangement  of  the  biotite,  a  fine-grained  granitoid  rock  results,  like  the 
best  at  the  Monson  quarry,  though  it  is  nowhere  so  completely  granitoid 
as  at  the  Middlefield  and  Becket  quarries. 

'  Geol.  CoDn.  -Am.  .Jour.  Sci.,  1st  series,  Vol.  VI,  1823,  p.  19. 


THE  ORANGE  AND  MONSON  AREA.  59 

PETKOGRAPHICAL  DESCRIPTION. 

As  the  type  of  the  Monson  gneiss  the  rock  of  Flynt's  quarry  at 
Mouson  is  naturally  taken  for  detailed  description,  and  for  this  purpose 
fine  specimens  of  the  two  varieties  which  served  for  the  analyses  quoted 
on  page  62  wei'e  kindly  furnished  me  by  the  proprietor  of  the  quarry, 
Mr.  W.  N.  Flynt,  and  form  the  material  of  the  following  description: 

(rt)  The  darker  variety  is  a  rather  dark  pure-gray  granitoid  rock  of 
medium  and  very  even  grain.  The  quartz  and  orthoclase  are  almost 
equally  colorless  and  glassy,  so  that  they  are  not  easily  distinguished;  the 
latter  is  disseminated  in  a  certain  small  porphyritic  way,  so  as  to  show  many 
shining  facets  upon  freshly  broken  surfaces.  The  black  constituent  is  pres- 
ent in  small  quantity,  but  from  the  translucency  of  the  other  constituents 
it  gives  a  quite  dark  color  to  the  mass.  It  is  this  translucency  which  causes 
the  marked  distinctions  between  the  dark  polished  and  the  white  pounded 
surface.  The  black  constituent  is  a  lustrous  black  biotite,  greenish-brown 
or  bright  emerald-green  by  transmitted  light.  It  is  arranged  with  very 
imperfect  parallelism,  and  yet  is  somewhat  concentrated  along  certain 
lamination  planes,  although  not  joined  into  membranes,  and  this  alone  gives 
the  rock  its  gneissoid  texture.  Seen  edgewise,  it  resembles  hornblende, 
but  I  have  not  detected  this  mineral  in  the  present  variety.  Wine-yellow 
grains  of  titanite  are  associated  with  it,  and  rarely  grains  of  a  light-red 
garnet.     Plagioclase  could  not  be  detected. 

The  biotite  is  often  changed  to  a  bright-green  chlorite,  and  parallel  there- 
with is  an  abundant  development  of  hematite  in  isolated,  regular  hexagonal 
plates  or  elongated  congeries.  A  few  deep-green  prisms  of  tourmaline 
occur,  short,  stout,  and  hemimorphic. 

(b)  The  lighter  variety  is  characterized  by  a  somewhat  coarser  grain. 
The  black  constituent  is  almost  equally  biotite  and  magnetite.  It  is,  how- 
ever, much  less  abundant  and  so  arranged  in  the  cleavage  planes  that  trans- 
verse to  these  the  rock  is  mottled  with  white  elongate  spots  from  which  it 
is  absent. 

The  important  distinction  between  the  two  is  in  the  fact  that  musco- 
vite  in  thin,  membranous  patches  is  quite  abundant  upon  the  lamination 
planes  of  this  variety.  This  is  an  exception  to  the  rule  that  muscovite  is 
absent  from  the  Becket  and  Monson  gneiss  in  the  three  river  counties  and 
characteristic  of  the  next  formation  above. 


60  GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

The  quartz  is  often  inclosed  in  the  orthoclase  in  wholly  rounded  grains. 
It  contains  great  swarms  of  cavities  of  large  dimensions  and  the  most  dis- 
torted shapes,  often  spun  out  into  long  capillary  tubes,  which  sometimes 
connect  distant  cavities.  Often  these  appear  empty;  often  they  contain  a 
fluid  with  large,  motionless  bubble;  sometimes  they  appear  to  contain  two 
fluids,  with  moving  bubble;  sometimes,  also,  they  are  negative  crystals, 
with  very  large  bubbles.  Rutile  needles  occur  rarely  in  the  quartz.  The 
orthoclase  is  in  large  cr}^stals  intergrown  with  albite.  The  plagioclase 
extinguishes  at  25°  to  28°,  is  optically  negative,  and  is  a  lime-soda- 
feldspar  near  anorthite.  Large  grains  are  free  from  multiple  twinning, 
except  near  the  borders,  where  it  is  caused  by  pressure. 

The  change  of  feldspar  to  muscovite  is  of  great  beauty.  Often  everj'- 
other  lamina  of  a  triclinic  feldspar  is  changed  to  a  mass  of  fine  nacreous 
scales,  the  intervening  laminae  being  unchanged. 

The  biotite  is  red-brown,  rarely  green,  and  then  associated  with  hex- 
agonal scales  of  hematite.  Zircon  occurs  in  small,  highly  refringent  prisms. 
Garnet  is  in  hyacinth-red  grains  and  dodecahedra,  inclosing  smaller  dodec- 
ahedral  crystals  or  cavities.  There  is  no  magnetite,  menaccanite,  or  titanite. 
Resume. — Friable,  light-gray,  medium  to  fine  grained  biotite-gneisses, 
which,  beyond  the  boundaries  of  the  county,  show  abundant  evidence  of 
their  derivation  from  conglomerates,  of  which  traces  are  not  wanting 
within  the  boundaries  of  the  three  counties  along  the  western  border,  but 
fail  almost  entirely  in  the  three  eastern  areas.  They  are  contrasted  with 
the  older  gneiss  by  the  failure  of  all  the  peculiarities  enumerated  at  the 
close  of  the  last  chapter  (p.  30)  and  marked  by  the  abundance  of  titanite 
in  pale,  flat  crystals,  both  macroscopically  and  microscopically  present. 
This  mineral  is  very  rare  in  the  older  gneisses,  except  in  or  near  limestone, 
and  it  occurs  there  in  larger  and  more  sharply  defined  crystals. 

Beds  of  hornblende-schist  are  almost  always  absent.  Important  beds 
of  a  fine  actinolite-quartzite  and  of  olivine-chromite-enstatite  rock,  with  fine 
contact  phenomena,  characterize  the  Pelham  area. 

THE  MONSON   QUARRY. 

The  following  account,  copied  from  the  Springfield  Republican  of 
May  9,  1884,  and  verified  as  to  its  accuracy,  may  find  a  place  here,  giving. 


THE  MONSON  QUARRY.  Gl 

as    it  does,  a  detailod   history   ot"  the   most   iiuportant   (jiiarry   in   western 
Massachusetts : 

"W.  N.  Flynt  &  Co.'s  granite  quarries,  situated  a  mile  north  of  tlie 
\-illage  of  Monson,  on  a  spur  track  of  the  New  London  Railroad,  were  first 
opened  eighty  years  ago  by  agents  of  the  United  States  Government,  who 
took  from  there  stone  for  the  foundation  of  the  Springfield  armory.  In 
1825  Rufus  Flynt  put  four  or  five  men  at  work  in  the  quarry  to  supply  the 
local  market,  and  tlie  front  of  the  Chicopee  Bank  building  in  this  city  was 
soon  afterwards  built  of  this  stone.  Since  1836  W.  N.  Flynt,  son  of  Rufus 
Flynt,  has  had  charge  of  the  work,  and  has  greatly  enlarged  the  business, 
until  at  present  the  yearly  output  of  stone  is  20,000  to  30,000  tons,  valued 
at  $150,000  or  $200,000.  In  1887  28,700  tons  were  produced,  and  in  1888 
33,460  tons. 

"The  quarry  land  owned  by  the  company  amounts  to  500  acres,  all 
underlain  by  granite,  only  a  small  part  of  which,  however,  has  yet  been 
worked.  The  stone  lies  in  horizontal  layers  from  1  to  12  feet  thick,  a,nd 
wedges  are  mainly  depended  upon  for  getting  out  even  the  largest  masses 
of  rock,  powder  being  used  only  to  lift  the  loosened  la3^er  from  its  bed. 
The  largest  single  piece  which  has  yet  been  taken  out  was  354  feet  long, 
11  wide,  and  4  high,  and  1,104  wedges  were  used  in  detaching  it. 

"The  present  workings  are  on  the  slope  of  a  hill,  and  although  75  feet 
below  the  crest  of  the  hill,  are  above  the  surrounding  country,  so  that  water 
gives  no  trouble  and  the  rock  is  the  more  easily  handled.  From  March 
to  December  about  100  quarrymen  and  40  stone  dressers  are  employed, 
and  during  the  winter  an  almost  equal  force  is  kept  at  work.  Last  3^ear 
(1883)  28,403  tons  of  granite  were  shipped,  and  in  all  branches  of  the 
work  between  600  and  700  men  were  employed. 

"Specimens  of  the  Flynts'  workmanship  are  shown  in  the  Monson 
Library,  costing  $35,000,  and  in  a  memorial  hall  now  being  constructed  at 
a  cost  of  $30,000,  in  both  of  which  the  light  and  dark  varieties  of  granite 
yielded  by  the  quai'ries  are  artistically  blended. 

"The  Church  of  St.  Francis  Xavier,  in  New  York  City,  was  also  built 
of  this  stone,  as  were  also  the  Walker  Hall  and  the  stone  churches  in 
Amherst." 


62 


GEOLOGY  OP  OLD  HAMPSHIEE  COUNTY,  MASS. 


The  following  letter  is  also  published  by  the  kind  permission  of  Mr. 

Flynt: 

Massachusetts  Institute  op  Technology, 

February  14, 1881. 
Messrs.  W.  N.  Flynt  &  Co. 

Gentlemen  :  The  two  sorts  of  Monsou  granite  which  were  sent  to  us  have  been 
carefully  averaged,  and  several  analyses  of  each  have  been  made,  with  the  following 
results : 


Silica 

Alumina 

Magnetic  oxide  of  iron 

Lime 

Magnesia 

Soda 

Potash , 

Sulpllur 

Copper 


Light. 


73.47 

15.07 

L15 

4.48 

.12 

5.59 

.38 

Trace. 

Trace. 


100. 26 


Dark. 


69.35 

18.83 

2.00 

5.94 


3.78 


99.90 


In  this  granite-mica  is  replaced  by  hornblende,'  as  in  the  Quincy  and  Eockport 
granites.  Such  stones  are  much  less  affected  by  chemical  agents  than  those  which 
contain  mica. 

The  percentage  of  the  alkalies,  potash  and  soda,  has  much  to  do  with  the  power 
of  resisting  atmospheric  influences.  The  amount  of  alkali  in  both  specimens  is 
uncommonly  small  for  granites.  The  sum  is  less  in  the  dark-colored  one,  because 
that  contains  a  much  larger  proportion  of  the  black  hornblende,  which  probably  is 
free  from  alkali.  The  potash  and  soda  come  from  the  feldspathic  ingredient  of  the 
mixed  minerals.  This  part  seems  to  correspond  nearly  to  andesite  rather  than  to 
ordinary  potash-feldspar. 

We  have  in  Hull's  Treatise  on  Building  and  Ornamental  Stones  the  analyses 
of  thirteen  European  granites,  which  show,  respectively,  as  the  sum  of  the  potash  and 
soda:  6.74,  7.27,  6.16,  7.91,  7.74,  7.98,  8.61,  9.67,  7.46,  5.63,  7.40,  5.82,  9.00  per  cent, 
while  the  Monson  granite  shows  5.97  and  3.78.  So  far  as  the  alkalies  are  concerned, 
the  dark  is  superior  to  all  of  the  thirteen,  and  the  light  is  better  than  all  except  the 
twelfth,  which  was  from  Mont  Blanc,  and  the  tenth,  which  was  from  Meineckenberg. 

The  iron  in  the  Monson  granites  is  in  the  form  of  magnetic  oxide,  which  is 
unchangeable.  Were  it  in  the  form  of  pyrites  it  would  be  liable  to  oxidize  and  would 
give  rusty  stains  on  long  exposure. 

'  This  is  a  mistake,  as  the  black  constituent  of  the  specimens  analyzed,  which  were  submitted 
to  me  for  study,  was  biotite.  The  alkali  determination  given  above  differs  greatly  from  that  given 
for  the  Beeket  gneiss  and  from  the  results  of  microscopical  examination,  which  indicate  the  presence 
of  potash-feldspar. 


THE  MONSON  GNEISS.  63 

As  far  as  we  may  jutlge  from  the  chemical  and  mineralogical  composition,  these 
Monsoii  granites  should  remain  practically  unchanged  for  an  indefinite  length  of  time, 
since  those  constituents  which  favor  disintegration  are  present  in  unusually  small 
proportion. 

Yours,  truly,  John  M.  Ordway, 

Professor  Industrial  Chemistry. 

STRENGTH  OP   THE   MONSON   GNEISS. 

Interesting  data  concerning  the  strength  and  durabihty  of  the  Monson 
granite  are  given  by  Mr.  A.  P.  Merrill.  A  block  7.6  by  7.4  inches,  placed 
with  the  bedding  horizontal,  was  crushed  by  a  weight  of  15,390  pounds  to 
the  square  inch,  and  one  6  by  6.1  inches,  with  the  bedding  vertical,  was 
crushed  by  a  weight  of  12,720  pounds  to  the  square  inch.^  These  results 
may  be  compared  with  those  given  for  the  Becket  rock  on  page  36. 

CONGLOMEKATE     STRUCTURE    IN    THE    MONSON    GNEISS,    AND     SUDDEN    EXPANSION    OF    THE    UOCK    IN 

QUARRYING. 

The  trimmings  of  Williston  Hall,  one  of  the  buildings  of  Amherst 
College,  was  made  of  rock  from  the  Monson  quarries.  I  had  been  familiar 
with  the  buildings  since  my  college  days,  and  I  was  startled,  two  years  ago, 
upon  observing  distinct  traces  of  pebbles  in  the  blocks  forming  the  coign  on 
the  northeast  corner,  especially  in  those  between  8  and  12  feet  from  the 
ground.  PI.  I,  coign  of  Williston  Hall,  Amherst  College,  represents  these 
blocks,  and  is  copied  from  a  photograph.  A  little  later  I  discovered  traces  of 
the  same  structure  in  the  quarry  at  Monson,  in  a  portion  of  the  rock  6  or  8 
feet  square,  near  the  surface  of  the  ledge,  and  a  rod  north  of  the  trap  dike 
that  intersects  the  quarry.  I  took  a  photograph  of  the  wall,  and  the  next 
year  found  the  whole  quarried  away  and  secured  a  photograph  of  one  large 
block  which  had  recently  been  blasted  from  the  spot.  These  pebbles  were 
uniformly  compressed,  so  that  they  were  of  a  flattened  egg-shape;  the 
shortest  diameter,  about  an  inch  or  an  inch  and  a  half,  was  east  and  west; 
the  next,  2  inches,  was  north  and  south,  and  the  longest,  nearly  3  to  4 
inches,  was  vertical.  The  foliation  here  stands  nearly  vertical  and  strikes 
north  and  south;  the  gneiss  lies  in  the  core  of  a  close-pressed  anticline, 
and  the  pebbles  have  been  flattened  in  the  foliation  plane  by  an  east-west 

'  stones  for  Building  and  Decoration,  New  York,  1891,  p.  406. 


64  GEOLOGY  OP  OLD  HAMPSHIRE  COUNTY,  MASS. 

force  and  were  able  to  expand  but  slightly  in  tlie  north-south  direc- 
tion because  of  the  resistance  of  the  adjacent  rock.  They  have  been 
extended  almost  entirely  in  the  vertical  direction,  but  as  this  naOtion  took 
place  against  the  great  weight  of  the  superincumbent  rock,  there  was  a 
strong  expansive  stress  or  resistance  in  the  north-south  direction,  and  it  is 
this  tendency  to  expansion,  still  stored  in  the  gneiss,  which  would  seem  to 
explain  the  sudden  north-south  elongation  of  blocks  of  the  rock  when  they 
are  quan-ied.  These  most  remarkable  phenomena  have  been  described 
fully  by  Professor  Niles.-^ 

The  face  of  the  quarry  looks  westerly,  and  horizontal  joint  planes  are 
utilized  in  quarrying.  Except  for  these  planes  the  rock  is  remarkably  free 
from  joints.  Slabs  3  to  5  feet  in  thickness  and  10  feet  wide  from  east  to  west, 
and  of  very  great  length  from  north  to  south,  are  split  off  by  a  long  line  of 
wedges,  and  while  one  end  of  the  rock  still  retains  its  connection  with  the 
ledge  the  other  expands  so  that  the  halves  of  the  drill  holes  fail  to  match. 
In  one  case,  in  1869,  a  block  4  feet  thick,  11  feet  wide,  and  354  feet  long 
was  split  by  the  use  of  nearly  1,200  wedges.  As  the  block  was  followed 
up  from  the  attached  end  the  halves  of  the  drill  holes  soon  ceased  to  match 
exactly,  and  this  increased  with  regularity  to  the  other  end,  where  the  elonga- 
tion amounted  to  an  inch  and  a  half  Many  such  cases  have  occurred  at  all 
seasons  and  times  of  the  day.  Several  were  carefully  studied  by  Professor 
Niles,  and  I  have  myself  seen  one  most  striking  case.  Where  a  long  line 
of  wedges  was  put  in  about  6  feet  back  from  the  quarry  face,  and  before 
the  cross  channel  was  cut  at  the  south  end  of  the  proposed  block,  the  crack 
started  of  itself  and  ran  beyond  the  line  of  the  wedges  for  a  long  distance 
to  the  north,  while  at  the  south  end  it  soon  left  the  line  of  the  wedges  and 
went  west,  and  ran  out  to  the  quarry  face,  and  the  expansion  then  caused 
the  block  to  project  at  the  south  end  westerly  over  the  face  of  the  quarry. 
As  much  as  10,000  tons  of  rock  have  been  quarried  out  by  a  single  fissure. 
,  In  the  same  way  the  expansion  causes  the  horizontal  sheets  of  the  rock 
to  rise,  often  quite  suddenly,  in  considerable  anticlines,  with  the  arch  as  much 
as  50  feet  long  and  the  rise  3  or  4  inches.  These  anticlines  forin  some- 
times with  explosive  violence,  throwing  large  fragments  of  the  rock  more 
than  2  feet  from  their  original  position.  The  large  area  of  shattered  rock 
produces  the  impression  of  a  small  but  violent  earthquake.     The  explosions 

1  Proc.  Boston  Soc.  Nat.  Hist.,  Vol.  XIV,  p.  80 ;  Vol.  XVI,  p.  41 ;  Vol.  XVIII,  p.  272 ;  and  Proc.  Am. 
Assoc.  Adv.  Sci.,  Vol.  XXII,  part  2,  p.  156. 


U.   S.   GEOLOGICAL  SURVEY 


MONOGRAPH  XXIX       PL. 


NORTHEAST  COIGN  OF  WILLISTON   HALL,   AMHERST  COLLEGE. 

Showing  the  Cambrian  conglomerate-gneiss  from  -the  Monson  quarry,  with  traces  of  pebbles,  and  shear 
zones  darkened  by  excess  of  biotite.  {The  pebbles  are  much  more  distinct  in  the  photograph  than 
in  the  repioduction,  especially  at  the  left.) 


THE  MONSON  (iNEISS.  65 

are  likened  by  the  miners  to  the  firing  of  a  blast,  and  have  been  heard  a 
mile  away  from  the  quarry. 

Professor  Niles  explains  the  phenomena  here  described  as  the  result  of 
a  force  of  compression  acting  from  north  to  south.  This  would  be  a  later 
exertion  of  the  same  mountain-making  force  which,  acting  from  east  to 
west,  has  folded  the  rocks  in  meridional  lidges.  I  know  of  no  independent 
evidence  of  the  replacement  of  the  east-west  force  by  a  later  north-south 
compression.  The  changes  of  level  in  the  Glacial  period,  and  along  our 
coast  in  later  ages,  seem  to  come  under  a  different  category. 

The  rock  is  certainly  in  a  state  of  elastic  compression  in  a  north-south 
direction  at  present,  while  the  last  traceable  dynamic  change  it  has  under- 
gone was  the  strong  east-west  pressure  which  crushed  its  pebbles  into  flat 
disks  and  caused  them  to  be  so  greatly  stretched  in  the  vertical  direction. 
In  the  resolution  of  this  force  some  portion  of  its  north-south  component 
seems  to  have  been  stored  in  the  rock  as  an  elastic  stress  which  expresses 
itself  in  expansion  when  the  surrounding  masses  are  removed. 

A   COMPLEX    MINEBAI,  VEIN   OF   THE    GNEISS. 

A  curious  vein  occurs  in  the  northwest  corner  of  the  Monson  quarry, 
adjacent  to  the  region  where  the  gneiss  is  highly  hornblendic.  The  earliest 
filling  of  the  vein  was  a  matted  mixture  of  pale-green,  fine-fibroiis  actino- 
lite,  granular  to  short-bladed  epidote,  clinochlore,  magnetite  in  octahedra,  a 
little  quartz,  and  colorless  prehnite  in  thin,  flat  blades  of  the  form  0  (001), 
oo  P  Ob  (010),  CO  P  CO  (100),  00  (110),  flattened  on  0  and  elongate  parallel 
to  the  short  axis.  They  are  very  minute,  but  were  determined  crystallo- 
graphically  by  fixing  the  position  of  the  optical  axes.  This  ends  with  a 
downy  surface  of  thin,  colorless  prehnite  blades,  and  a  second  series  begins 
with  calcite  in  fine,  transparent,  cleavable  masses,  followed  by  rich-green 
prehnite  in  rosettes  and  sheaf-like  forms,  upon  which  is  a  final  generation 
of  calcite  in  distinct  crystals — the  rhombohedron  R  with  its  edges  replaced 
by  a  scalenohedron. 

In  other  parts  of  the  vein  this  is  followed  by  laumontite,  at  first  inter- 
grown  with  the  prehnite  and  then  resting  upon  it.  It  is  in  fine,  large  crys- 
tals and  coarse-granular  crystalline  aggregates  of  pink-white  color.  The 
series  is  closed  by  a  leek-green  hornstone,  which  fills  the  vein  and  envelops 
the  laumonite. 

MON  XXIX 5 


CHAPTER   YT. 

THE    LOWER    SILURIAN    SERICITE-SCHISTS  AND  AMPHIBO- 
LITES  ON  THE  WEST  SIDE  OF  THE  VALLEY. 

THE  HOOSAC   SCHIST  =  THE  ALBITIC  MICA-SCHIST.' 

Next  east  of  and  next  above  the  Becket  gneiss  a  continuous  band  of 
feldspathic  inica-schist,  often  sericitic,  crosses  the  State,  and  the  in-egular 
western  boundaries  of  the  counties  here  studied  include  three  portions 
thereof  within  Monroe,  Middlefield,  and  Blandford,  while  a  loop  of  the 
same  rock  is  brought  up  in  the  Grranville  anticline. 

The  bed  has  so  decidedly  the  habit  of  a  mica-schist  and  is  so  closely 
associated  with  the  mica-schist  next  above  that  I  have  chosen  the  name 
"albitic  mica-schist"  rather  than  gneiss  for  it.  At  its  northern  extremity, 
however,  the  amount  of  feldspar  increases  and  the  rock  becomes  a  gneiss, 
porphyritic  with  small  crystals  of  albite.  It  is  shown  below  that  this  is 
the  Grreen  Mountain  gneiss  of  Adams.  At  the  base  of  this  formation  a 
dark,  highly  garnetiferous  mica-schist  forms  the  passage  bed  from  the 
Becket  gneiss  to  the  main  portion  of  the  series.  The  latter  has  the  habit 
of  a  mica-schist,  although  it  is  generally  quite  feldspathic.  The  small, 
rounded  crystals  of  albite  scattered  porphyritically  in  the  mass  have  often 
in  crystallizing  cemented  several  grains  of  quartz  together.  Both  micas 
are  present,  and  the  rock  is  generally  quite  dark  from  the  abundant  biotite. 
It  shares  with  the  following  formation  the  greasy  feel  from  the  hydration 
of  its  muscovite.  Where  it  crosses  the  Boston  and  Albany  Railroad  the 
basal  garnetiferous  schist  has  disappeared,  and  the  whole  series  is  from 
the  base  up  a  light-gray,  quartzose  sericite-schist,  porphyritic  with  many 
small,  rounded  albite  crystals,  which  often  cement  the  quartz  grains. 

'  Base  of  the  talcose  schist  of  President  Hitchcock. 
66 


THE  HOOSAO  SCHIST.  gy 

THE    MONROE    AREA. 

Prof.  C.  H.  Adams  introduced  the  name  Grreen  Mountain  gneiss  for 
the  o-ueiss  of  the  Green  Mountain  range  in  Vermont,  in  lii.s  first  report/  but 
without  definition  or  detail.  The  name  occurs  in  his  eimmeration  of  the 
primary  rocks,  between  talcose  slate  and  gneiss  proper,  and  he  remarks  that 
in  and  south  of  Mount  Holly  the  gneiss  replaces  more  or  less  the  talcose  slate. 

In  the  second  report  of  Professor  Adams  ^  is  a  letter  from  President 
Hitchcock,  who  calls  attention  to  the  fact  that  the  broad  band  of  gneiss 
which  makes  the  axis  of  the  Green  Mountains  across  Vermont  seems  in 
Massachusetts  to  be  replaced  suddenly  by  mica-slate,  and  fears  an  appear- 
ance of  discrepancy  between  the  maps  of  the  two  surveys  if  the  gneiss  is 
made  to  run  up  to  the  south  line  of  Vermont.  He  expresses  the  belief  that 
the  rocks  change  on  the  strike  in  the  neighborhood  of  the  State  line,  and 
adds  that  much  of  the  rock  is  halfway  between  gneiss  and  mica-slate. 

In  his  own  final  report  on  the  geology  of  Vermont^  President  Hitch- 
cock says  that  Professor  Adams  gave  the  above  name  to  distinguish  from 
true  gneiss  this  range  of  gneiss,  which  is  characterized  by  a  deficiency  of 
feldspar,  so  that  the  rock  is  often  mica-schist,  or  at  the  best  feldspathic 
mica-schist. 

On  a  later  page*  reference  is  made  to  the  sudden  change  of  the  Green 
Mountain  gneiss  into  the  gneiss  and  mica-schist  of  the  Hoosac  range,  and 
this  change  is  explained  thus: 

1.  The  mica-schist  of  Hoosac  Mountain  and  the  gneiss  of  the  G-reen  Mountains 
belong  to  the  same  formation,  and  the  Massachusetts  stratum  of  mica-schist  becomes 
gneiss  extremely  near  the  State  line  by  the  addition  of  a  little  feldspar.  It  is  a  case 
of  the  metamorphism  of  one  rock  into  another. 

2.  There  is  a  narrowing  of  the  formations  very  near  the  State  line.  Both  the 
gneiss  formation  and  the  mica-schist  curve  to  the  westward,  so  that  in  Massachusetts 
the  mica-schist  and  gneiss  are  narrower  than  in  Vermont. 

It  will  be  seen  below  that  the  Green  Mountain  gneiss  in  Heath  and 
Monroe  dips  beneath  and  does  not  pass  into  the  mica-schist  of  the  Hoosac 
range. 

1  First  Ann.  Rept.  Geology  of  Vermont,  1845,  p.  62. 
5^  Second  Ann.  Eept.  Geology  of  Vermont,  1846,  p.  248. 
3  Rept.  Geology  of  Vermont,  Vol.  I,  1861,  p.  454. 
"Ibid.,  p.  462. 


68        GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

In  a  later  section,  signed  specially  by  President  Hitchcock/  this  is 

said : 

On  the  south  line  of  Massachusetts  almost  the  whole  breadth  of  the  range,  not 
less  than  20  miles,  is  tolerably  well  characterized  gneiss.  Yet  as  we  pass  northerly 
on  the  line  of  strike  along  the  eastern  margin  the  gneiss  is  rapidly  succeeded  by  mica 
and  talcose  schist,  and  the  gneiss  becomes  so  pinched  up  as  to  form  a  mere  wedge 
before  we  get  across  the  State;  and  it  is  doubtful  whether  the  mica-schist  does  not 
absolutely  cut  off  the  gneiss  ere  we  reach  the  north  line.  We  incline  to  the  opinion, 
however,  that  a  narrow  belt  of  Green  Mountain  gneiss  does  extend  across  the  whole 
State. 

In  accordance  with  this  opinion,  a  band  of  gneiss  is  represented  in  the 
section  through  Hoosac  Mountain  on  the  line  of  the  tunnel  and  occupying 
its  middle  third.^ 

These  further  details  are  given  concerning  the  gneiss  along  the  north 
border  of  the  State: 

The  eastern  part  of  this  range  as  it  first  appears  in  Vermont  is  a  very  distinct 
gneiss.  ...  It  lies  much  to  the  east  of  the  Green  Mountains.  .  .  .  That  which 
forms  the  axis  of  the  Green  Mountains  in  the  southeast  part  of  Stamford  is  scarcely 
distinguishable  from  mica-schist.  ...  In  the  village  of  Stamford  and  at  Hart- 
wellville  the  gneiss  almost  passes  into  quartz  rock.     .     .    . 

In  Whitingham  and  Readsboro  there  is  a  large  amount  of  dolomite  and  saccha- 
roid  limestone  present  in  the  gneiss  in  the  form  of  beds.  The  gneiss  west  of  Deer- 
field  River  in  Readsboro  is  rather  peculiar.  It  is  a  very  coarse,  greenish,  massive 
rock,  sometimes  containing  multitudes  of  garnets  and  blotches  of  what  resembles  clay 
slate.  Most  of  the  course  of  Deerfield  River  in  Vermont  lies  in  the  trough  of  a 
synclinal.  Hence  the  strata  of  gneiss  in  a  part  of  their  course,  as  in  Wilmington, 
are  nearly  horizontal.^ 

Distribution. — An  inspection  of  the  map  will  show  that  the  Hoosac  schist 
extends  farther  east  here  (at  the  north)  than  farther  south,  and  that  its  upper 
boundary  is  more  irregular.  Entering  the  town  of  Rowe  from  Vermont,  the 
upper  boundary  goes  southwest  across  that  town,  crosses  the  Deerfield  River 
at  the  northwest  corner  of  Florida,  and,  bending  in  a  great  semicircle  open 
to  the  north,  it  leaves  the  county  across  the  west  line  of  Mom-oe,  so  that 
nearly  the  whole  of  this  town  is  underlain  by  this  rock  in  a  broad  anticline, 
with  north-south  axis  and  sharp  southward  pitch. 

North  of  the  tunnel  entrance,  at  the  last  house  on  the  river  road  before 
the  Monroe  line  is  reached,  the  Hoosac  schist  is  abundantly  exposed  behind 
the  house  and  800  feet  south  of  the  line,  while  about  the  same  distance 
farther  south  the  overlying  Rowe   schist  occurs.     The  latter  is  a  much 

'  Kept.  Geology  of  Vermont,  Vol.  1, 1861,  p.  470.  =  Ibid.,  pi.  15,  fig.  5.  » Ibid.,  p.  463. 


THE  HOOSAO  SCHIST.  69 

(•i-unii)le(l  inag-iietite-beann<^-  luusoovite-scliist  (the    mica  often  hydrated), 
witli  an  abnndance  of  tlie  t-liaracteristic  chlorite. 

The  Hoosac  schist  appears  in  its  usual  development  as  a  small  por- 
phyritic  mica-schist  or  augen-gneiss  It  very  closely  resembles  the  Rowe 
schist  above,  except  (1)  that  it  is  darker  and  (2)  that  there  are  developed 
in  large  numbers  between  the  folia  small,  rounded  grains  of  feldspar  2 
to  3"™  across,  so  that  the  rock  may  be  called  a  feldspathic  hydromica-  or 
sericite-schist.  It  contains  the  same  chlorite  as  the  rock  above,  though  in 
greatly  lessened  quantity.  It  thus  differs  decidedly  from  the  granitoid 
gneiss  of  Becket  and  Shelburne.  Its  feldspars  have  been  determined  by 
Dr.  J.  E.  Wolff  to  be  albite,  though  as  a  rule  they  lack  the  tri clinic  striation 
on  cleavao-e  faces.  The  Hoosac  and  Rowe  schists  both,  strike  N.  80°  E.  and 
dip  S.  60°  at  this  point,  so  that  the  former  dips  beneath  the  latter. 

Going  west,  the  boundary  closely  follows  Mill  Bi-ook,  arching  round 
to  the  northwest,  and  crosses  the  road  to  Florida,  just  south  of  where  this 
brook  crosses  it,  with  a  strike  of  N.  30°  W.,  the  Hoosac  schist  dipping  65°  S. 
beneath  the  Rowe  schist.  Still  following  the  curvature  of  the  brook,  the 
Hoosac  schist  strikes  east-west  south  of  C  Stafford's  sawmill  and  dips  30°  S. 
beneath  the  Rowe  schist,  and  the  beds  continue  in  this  posture  to  the  west 
line  of  the  town.  Both  the  Hoosac  and  the  Rowe  schists  are  quite  uniform 
in  character  along  this  line. 

From  the  point  of  starting  on  the  Deerfield  River,  the  boundary  bends 
around  to  the  northeast,  crossing  the  road  from  Monroe  to  Rowe  just  south 
of  the  second  brook-crossing  and  north  of  J.  F.  Brown's,  with  a  strike  of 
40°  E.,  the  gneiss  dipping  40°  SE.  beneath  the  schist.  The  Hoosac  is  here 
a  dark,  subporphyritic,  gneissoid  biotite-mica-schist.  Farther  on  it  swings 
round  to  run  N.  20°  E.  and  dips  20°  E.  and  crosses  the  town  line  with  the 
most  westerly  of  the  roads  from  Rowe  into  Vermont,  far  to  the  west  of  the 
point  where  upon  the  Vermont  map  the  corresponding  boundary  is  made 
to  cross  the  State  line.  The  boundary  is  well  defined  in  Massachusetts,  and 
especially  well  exposed  where  it  crosses  the  Monroe-Rowe  road  in  a  ravine 
visible  to  the  east  from  the  road.  One  sees  to  the  left  (northwest)  the 
whole  hillside  made  up  of  the  subporphyritic  gneiss  (Hoosac),  to  the  right 
a  dark,  rusty,  barren  mica-schist  (Rowe). 

The  boundary  of  the  Hoosac  schist  upon  the  Becket  gneiss  below  is 
found  far  beyond  the  border  of  the  county  to  the  west,  and  Dr.  J.  E.  Wolff 


70  GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

was  so  kind  as  to  guide  me  to  it.  Just  south  of  where  the  tunnel  crosses 
the  west  hne  of  Florida  the  Becket  gneiss  wraps  around  the  Archean 
nucleus  of  Hoosac  Mountain  and  the  feldspathic  mica-schist  wraps  around 
the  Becket  gneiss,  and  Dr.  Wolff  called  my  attention  to  the  fact  that  the 
mica-schist  is  at  base  a  rather  dark  garnetiferous  mica-schist. 

Thickness. — I  have  not  been  able  to  form  an  opinion  concerning  the 
thickness  of  the  Hoosac  schists  from  this  region.  They  are  cut  across  in 
the  Hoosac  Tunnel  and  are  7,000  feet  thick  measured  horizontally,  and 
this  with  a  mean  dip  of  35°  would  give  4,000  feet  for  their  thickness,  but  it 
is  not  certain  that  the  section  is  free  from  repetitions  or  faults. 


THE  MIDDLEFIELD  AREA. 

The  band  of  Hoosac  schist  continues  from  the  point  where  it  leaves 
Monroe,  in  Franklin  County,  a  little  east  of  south  across  Berkshire  County 
to  the  point  where  it  enters  Middlefield,  in  Hampshire  County ;  and  in  all  this 
distance  (24  miles)  I  have  found  the  bed  to  maintain  its  character  unchanged. 
There  is  a  garnetiferous  mica-schist  stratum  at  the  base,  and  above  this  a 
heavy  bed  of  a  feldspathic  mica-schist  fairly  well  deserving  this  name,  as  it 
is  not  so  albitic  as  that  in  Monroe.  It  changes  everywhere  rather  suddenly 
into  the  stratum  above,  the  change  consisting  only  in  the  disappearance  of 
the  porphyritic  albites  and  part  of  the  mica,  the  rocks  being  otherwise  alike. 

In  both  the  mica  is  very  extensively  hydi-ated  and  greasy  to  the  feel, 
and  the  rocks  have  been  called  talcose  schists,  talcoid  schists,  and,  lastly, 
hydromica-  or  sericite-schists.  It  is  generally  barren,  but  in  some  bands 
is  garnetiferous.  The  garnets  are  uniformly  quite  large — 12  to  15°""  may 
be  an  average — and  are  widely  scattered  through  large  beds  of  the  rock, 
not  often  massed  together  in  a  single  layer,  as  in  the  calciferous  mica- 
schist.  They  are  almost  always  trapezohedra,  while  in  the  last-mentioned 
schist  they  are  rhombic  dodecahedra.  They  are  often  surrounded  by  a  layer 
of  chlorite,  which  has  sometimes  wholly  replaced  the  gai'net,  and  scattered 
bunches  and  scales  of  the  same  green  mineral  appear  everywhere  on  the 
cleavage  surfaces  of  the  schists,  distinguishing  this  and  the  Rowe,  Savoy, 
and  Hawley  schists  from  all  others  in  the  series.  The  micaceous  minerals 
are  generally  present  in  but  small  quantity,  and  much  of  the  rock  could 
be  described  as  a  micaceous  quartz-schist. 


THE  HOOSAC  SCHIST.  71 

As  it  blends  soutliwardh'  with  the  Uowe  schist,  which  becomes  t'eld- 
spathic,  and  as  it  is  liere  also  doubled  by  its  reappearance  in  East  Grranville, 
the  whole  of  its  southern  portion  was  associated  with  the  gneiss  below  by 
President  Hitchcock,*  though  in  his  first  publication  he  suggests  doubtfully 
"the  passage  of  the  mica-schists  into  gneiss  along  the  line  of  strike,"  and 
reiterates  the  idea  more  decidedly  in  the  first  report  on  the  geology  of 
Massachusetts."  He  continues,  however,  to  color  his  map  in  accordance 
with  the  lithological  character  of  the  rock,  representing  the  gneiss  as  a 
broad  wedge,  tapering  northward,  and  the  mica-schist  as  a  wedge  of  about 
equal  size,  tapering  southward  and  scarcely  reaching  the  south  line  of 
the  State.  Prof.  C.  H.  Hitchcock,  from  a  study  of  the  data  given  by  his 
father,  and  of  Percival's  report,  has  in  part  corrected  this  in  a  map  published 
in  Walling's  Atlas  of  the  State  of  Massachvisetts.' 

SECTION  ALONG  THE  BOSTON  AND  ALBANY  RAILROAD. 

The  variety  presented  by  the  schist  from  below  upward  is  well 
illustrated  by  a  continuation  of  the  section  along  the  railroad  from  the 
point  reached  upon  page  32.  Just  east  of  Bancroft  station,  where  Factory 
Brook  joins  the  Westfield  River,  the  lowest  bank  of  Hoosac  schist  rests 
upon  the  granitoid  Becket  gneiss  with  clear  unconformity.  It  is  a  well- 
defined  hydi-omica-schist,  light-gray,  quartzose  and  thin-fissile,  but  porphy- 
ritic  with  an  abundance  of  small  albite  crystals,  which  are  of  rounded 
outline  and  are  filled  with  the  quartz  grains  in  the  midst  of  which  they 
have  formed. 

Twenty  rods  east,  at  the  beginning  of  the  cutting,  the  green-spotted 
hydromica-schist  carries  large,  fine  garnets  (co  0),  and  alternates  tln-ough 
the  cut  with  sandy  gneissoid  layers — layers  which  are  gneiss  in  composition, 
but  of  an  arenaceous  texture,  like  that  of  the  Devonian  feldspathic  quartz- 
ites  described  later  from  Bernardston,  rather  than  that  of  the  older  gneisses. 
The  appearance  of  the  rock  is  as  if  a  later  development  of  feldspar  and  mica 
in  a  sandstone  had  transformed  the  rock  into  a  gneiss  which  retains  a  sandy 
texture  very  different  from  that  of  the  lower  gneisses,  where  the  constituents 
are  closely  interwoven. 

On  passing  the  second  bridge  the  hydromica-schist,  still  feldspathic,  is 

>  Geology  of  the  Connecticut :  Am.  Jour.  Soi.,  Ist  series,  Vol.  VI,  1828,  p.  19. 
=  Geology  of  Massachusetts,  1835,  p.  332. 
3  Boston,  1871. 


72  GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

filled  with  flattened  lenses,  placed  witli  the  bedding,  of  quartz  and  of  quartz 
and  feldspar ;  and  from  this  point  the  road  runs  for  nearl}^  a  mile  through 
an  almost  continuous  cutting  of  the  light-gray,  flat-bedded  hydromica- 
schists  belonging  to  the  next  series — the  Rowe  schists,  which  are  without 
accessory  minerals  of  any  kind  and  preserve  a  monotonous  uniformity. 
The  dip  is  nearly  vertical,  and  the  section  line  is  nearly  at  right  angles  to 
the  strike. 

RELATION   TO   THE   BECKET   GNEISS. 

It  has  been  already  stated  that  at  the  brook  junction  east  of  Bancroft 
station  the  change  from  the  compact,  flesh-colored,  granitoid  gneiss  of  the 
Becket  series  below  to  the  porphyritic  hydromica-schist  is  abrupt;  The 
contact  between  the  two  is  exposed  for  a  good  distance  and  is  a  fissure,  the 
rocks  not  being  welded  together,  and  the  discordance  in  strike  is  consider- 
able and  in  dip  very  large.  There  is  certainly  unconformity  and  probably 
faulting  at  this  point,  but  the  nearness  of  the  point  to  the  area  where  the 
Becket  gneiss  is  so  irregularly  wrapped  around  the  southern  end  of  the 
Hinsdale  gneiss,  and  the  fact  that  the  Becket  gneiss  is  peculiarly  irregular 
in  structure  clear  up  to  the  junction,  make  it  possible  that  this  unconformity 
is  only  local,  and  at  all  events  deprive  it  of  a  decisive  weight  in  setthng  the 
question  of  real  unconformity.  The  junction  can  be  well  followed  north 
from  the  railroad  to  the  center  of  Middlefield,  and  the  series  retains  exactly 
its  character,  showing  a  great  development  of  feldspathic  hydromica-schists 
and  imperfect,  sandy  gneisses,  and  above  these  a  much  greater  mass  of 
barren,  gray,  and  green-blotched  schists,  belonging  to  the  Rowe  schists. 
The  transition  between  the  two  series — the  gneiss  and  the  feldspathic 
schist — is  best  studied  between  the  village  and  the  Fair  Grounds  in  Middle- 
field  Center. 

Just  below  the  point  where  the  roads  join  at  M.  Smith's,  south  of 
the  Fair  Grounds,  the  Rowe  hydromica-schist,  while  retaining  exactly  its 
dip  and  strike  (strike  N.  10°  E.,  dip  70°  to  80°  E.),  its  flat-fissile,  schistose 
appearance,  its  gray  surface  spotted  with  green,  and  the  multitude  of  small 
corrugated  and  twisted  quartz  lenses,  becomes  indistinctly  porphyritic,  the 
feldspar  here  and  there  cementing  together  a  group  of  sand  grains.  As  one 
goes  lower  (i.  e.,  westerly)  this  alternates  many  times  in  thick  and  thin 
beds  with  the  common  hydi'omica-schist,  often  chloritic,  until  the  beds 
which  strike  through  the  Fair  Grounds  become  a  quite  well-characterized 


THE  IIOOSAC  SCHIST.  73 

gneiss,  but  still  tilled  with  the  small  tortuous  quartz  veins,  and  differing 
from  the  Beeket  gneiss  below  by  the  presence  of  two  micas,  the  muscovite 
being  the  prevailing  variety.  In  the  village  itself,  but  a  few  rods  farther 
west,  the  true  Becket  gneiss  appears  and  occupies  all  the  region  westward 
with  exactly  the  same  strike  and  the  same  high  dip,  and  though  the  exact 
line  of  contact  is  not  exposed,  there  is  nothing  to  suggest  unconformity. 
Everything  here  points  to  a  gradual  passage  of  the  gneiss  up  into  the 
hydromica-schist.  On  the  other  hand,  the  rocks  here  all  stand  vertical  side 
by  side  and  have  been  subjected  to  the  greatest  compression,  and  the  traces 
of  an  unconformity  of  considerable  importance  may  well  be  masked. 

However,  going  south  from  the  railroad  across  Becket,  Blandford,  and 
Tolland,  along  the  winding  junction  line  of  the  two  formations,  one  finds 
marked  evidence  of  a  considerable  unconformity,  in  that  while  the  newer 
formation  conforms  in  strike  to  the  undulations  of  tlie  boundary  line,  dip- 
ping away  from  it  to  the  east,  the  strike  of  the  older  is  in  all  this  distance 
uniformly  N.  40°  to  45°  E.,  almost  at  right  angles  to  the  boundary,  and 
thus  to  the  strike  of  the  newer  rocks. 

I  conclude  that  the  unconformity  between  the  two  formations  is 
general,  and  that  the  feldspathic  character  of  the  lower  half  of  this  forma- 
tion is  due  to  its  derivation  from  the  older  gneisses,  against  which  it  rests 
in  the  form  of  a  coarser,  feldspathic  material,  while  the  upper  portion  was  a 
more  arenaceous  sediment,  largely  deprived  of  its  alkaline  constituents,  and 
this  conclusion  seems  to  me  strengthened  by  the  study  of  the  same  junction 
on  the  east  side  of  the  Connecticut. 

THE    GRANVILLE    AREA. 

This  area  comprises  Blandford,  Tolland,  and  Granville,  in  Hampden 
County,  and  Hartland  and  Granby  in  Connecticut. 

South  of  the  railroad  section  given  above,  along  the  south  line  of  Mid- 
dlefield,  the  feldspathic  mica-schist  continues  across  Becket  in  Berkshire 
County  to  its  southeast  corner,  and  there  it  enters  the  Granville  quadrangle  at 
its  northwest  corner,  and  at  the  same  time  Hampden  County.  Its  relations, 
especially  to  the  Rowe  schist  above,  can  best  be  studied  on  the  road  west 
from  Chester,  where  the  pale  greenish-gray  hydromica-schist  (Rowe  schist) 
succeeds  the  hornblende-schist  as  one  goes  west  from  the  Emery  mine, 
and  is  well  exposed  at  the  iron  watering  trough.     Just  beyond  the  first 


74  GEOLOaY  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 

bridge  in  Becket  the  gray,  garnetiferous,  feldspathic  mica-schist  sets  in  and 
continues  to  the  sawmill,  where  the  Becket  gneiss  appears  in  a  large  quarry. 
Still  farther  south,  in  the  west  comer  of  Blandford,  the  Rowe  schist  narrows 
and  occupies  only  the  width  of  the  North  Meadow  Pond,  but  is  still  a  well- 
defined  band  of  sericite-schist,  while  the  Hoosac  schist  retains  its  width  and 
appears  in  the  high  hills  west  of  North  Blandford. 

Two  miles  farther  south,  at  Blair  Pond,  the  rock  from  the  Becket  gneiss 
below  to  the  liornblende-serpentine  band  above,  and  including  thus  both  the 
Hoosac  and  Rowe  schists,  is  a  rather  coarse  mica-schist,  not  sericitic,  but 
quite  feldspathic,  and  in  places  abounding  in  staurolite  crystals.  The 
country  begins  in  this  latitude  to  abound  in  granite  stocks  and  swarms  of 
dikes,  and  the  feldspathic  character  of  the  schists  seems  to  depend  largely 
on  an  impregnation  from  this  granite,  and  the  feldspathic  constituent  is 
arranged  in  flat  blotches  on  the  foliation  faces,  rather  than  in  abundant  small 
porphyritic  crystals,  as  is  the  case  farther  north.  The  lithological  dis- 
tinctness of  the  Hoosac  schists  and  the  Rowe  schists  disappears,  from  the 
loss  of  the  hydrated  mica  in  the  upper  bed  and  of  the  porphyritic  albite 
in  the  lower,  and  I  have  not  tried  to  separate  the  two  beds  in  the  Granville 
quadrangle. 

By  the  development  of  three  anticlines  in  these  schists,  in  the  two  outer 
of  which  the  Becket  gneiss  comes  to  the  surface,  and  by  the  troughing  out 
of  the  hornblende-schists  in  the  intervening  synclines,  this  complex  expands 
eastwardly  to  cover  the  whole  of  the  Granville  quadrangle,  wrapping  around 
the  separate  area  of  gneiss  in  East  Granville  and  Granby.  (See  map,  PI. 
XXXIV.) 

Granite  continues  abundant,  and  the  rock  becomes  in  the  whole  south- 
ern portion  of  the  Granville  qviadrangle  a  very  coarse  muscovite-biotite- 
schist,  showing  on  foliation  faces  continuous  films  of  large  muscovite  plates, 
or  muscovite  and  biotite  regularly  intergrown,  Avith,  at  times,  feldspar  or 
pegmatitic  quartz-feldspar  masses  in  the  interstices,  in  place  of  the  usual 
granular  quartz.  Toward  the  base  of  this  complex  on  its  western  border, 
and  in  better  development  around  the  Granville  gneiss,  is  a  rock  of  very 
attractive  appearance.  It  is  a  white,  gneissoid  rock  of  rather  coarse  grain. 
In  the  limpid,  gramilar  quartz  mass  the  rather  distant  scales  of  silvery  musco- 
vite, pale-red  biotite,  and  pyrite  are  compressed  into  perfect  parallelism,  so 
that  on  foliation  faces  a  very  bright,  silvery  luster  occurs.     Considerable  well- 


THE  HOOSAO  SOMLST.  75 

striated  plugioclase  appears  in  limpid  grains  in  tlie  granular  quart/,  ground, 
and  the  rock  is  the  gneissoid  development  of  the  albitic  Hoosac  schists, 
whose  places  it  takes,  though  it  did  not  seem  constant  enough  to  furnish  a 
basis  for  the  division  of  the  rock  in  mapping. 

HORNBLENDIC    BANDS    IN    THE    ALBITIC    MICA-SCHIST. 

Along  the  eastern  portion  of  the  area,  on  the  east  slope  of  Sodom 
Mountain,  in  Granville,  bands  of  nodules  of  a  pale-green  actinolite-garnet 
rock  occur,  of  a.  type  which,  so  far  as  I  have  observed,  has  always  been 
derived  from  limestone. 

On  the  west  slope  of  the  same  mountain  is  a  narrow  band  of  flat, 
fissile,  garnetiferous  hornblende-schist  of  gneissoid  structure.  The  horn- 
blende is  in  black,  shining  grains,  and  the  mass  of  the  rock  is  black,  but  is 
closely  spotted  with  round,'  whitish  spots  4-6""  in  cross-section,  in  which 
the  hornblende  is  in  larger  crystals  but  much  less  abundant.  Farther  south 
the  same  rock  contains  garnets  of  the  same  size  and  arrangement  as  the 
whiter  spots,  so  that  it  seems  the  hornblende  may  have  been  kept  out  of 
these  spaces  by  garnets  which  have  since  disappeared,  to  give  place  to  a 
later  development  of  larger  crystals  of  hornblende. 

THE  SHELBURNE  FALLS  ANTICLINE. 

Nearly  everywhere  around  the  Shelburne  Falls  anticline  hornblende- 
schist  seems  to  rest  directly  upon  the  gneiss,  and  in  several  places  it  can  be 
seen  to  do  so,  but  on  the  west  side,  near  J.  W.  Whitney's,  there  occurs  just 
below  the  hornblende-schist  a  white  quartzite  containing  distant  scales  of 
biotite,  magnetite  octahedra,  and  rutile  needles.  This  may  be  taken  as  a 
possible  remnant  of  the  hydromica-schist  series.  .  (See  section  3  of  the 
Hawley  section  sheet,  PI.  XXIV.) 

Accessory  minerals. — Excepting  garnet,  which  occurs  locally  in  the 
greatest  abundance  in  large  crystals  (12-20""),  generally  with  trape- 
zohedral  form,  the  formation  is  very  poor  in  accessory  minerals. 

Staurolite  occurs  in  quite  good  crystals,  in  both  forms  of  twinning,  on 
the  road  west  of  Blair's  pond,  in  Blandford. 

Cyanite  appears  in  gray  crystals  just  where  the  formation  crosses  the 
State  line  on  the  south,  and  near  the  south  line  of  Blandford  on  the  West 
Granville  road. 


76  GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

THE  ROWE  SCHIST=THE  LOWER  SERICITE-  OR  HYDROMICA-SCHIST. 

For  two-thirds  of  the  way  across  the  State,  starting  from  the  north, 
the  stratum  between  the  albitic  mica-schist  below  and  the  interrupted  horn- 
blende-serpentine band  (the  Chester  amphibolite)  is  a  thick  but  extremely 
monotonous  bed;  and  as  for  the  purpose  of  working  out  the  architecture 
of  the  region  every  valid  distinction  needs  to  be  utilized,  I  have  marked 
this  bed  separately  from  the  Hoosac  schist  as  far  south  across  the  State  as 
practicable.  It  is  the  rock  of  the  first  7,000  feet  of  the  Hoosac  Tunnel. 
In  Hampden  County,  as  already  indicated,  it  becomes  feldspathic,  and  can 
not  be  easily  distinguished  from  the  band  below,  as  it  is  followed  south 
from  that  region. 

FRANKLIN    COUNTY. 

The  schist  enters  Franklin  County  from  the  south,  across  the  line 
between  the  east  portal  of  the  tunnel  and  the  great  serpentine  deposit  at 
E.  King's,  nearly  a  mile  east,  and,  with  high  dips  to  the  southeast,  bends 
around  the  south  end  of  the  Grreen  Mountain  gneiss,  and  extends,  with  a 
width  of  a  mile,  northeast  into  Vermont. 

At  the  tunnel  portal  and  east  to  the  serpentine  it  is  a  very  quartzose, 
pale-green,  hydromica-schist,  stretched  so  that  it  has  often  a  ligniform 
structure.  It  contains  a  few  garnets,  trapezohedra,  and  many  flattened 
lenses  of  quartz,  which  rarely  contain  dolomite. 

Followed  northeast,  where  it  crosses  the  Rowe-Monroe  road  it  is  very 
chloritic  in  its  upper  portion,  and  at  the  base  is  a  dark,  rusty  mica-schist, 
resembling  the  Conway  schist. 

A  thin  section  was  cut  from  the  rock  4,000  feet  from  the  east  portal  of 
the  tunnel ;  it  is  a  light-gray,  schistose  rock  of  greasy  feel,  a  true  sericite- 
schist,  from  whose  powder  the  magnet  removes  much  magnetite.  It  shows 
under  the  microscope  a  mosaic  of  fine  quartz  grains,  dusted  with  magnetite 
and  wrapped  around  with  muscovite  and  pale-green  chlorite  scales. 

HAMPSHIRE    COUNTY. 

As  the  Rowe  schist  crosses  Middlefield  it  has  the  same  monotonous 
character.  It  is,  however,  more  garnetiferous,  and  the  garnets  are  very 
generally  chlorite-bordered,  and  on  foliation  faces  blotches  of  chlorite 
appear  mixed  with  the  hydrated  mica. 


THE  ROWE  SCHIST.  77 

It  is  bt'st  studied  in  the  ccmtiiuiiitiou  of  the  section  along-  the  Boston 
and  Albany  Railroad,  beginning  at  the  point  reached  on  page  72,  at  the 
second  bridge  east  of  Middlefield  station.  There  is  from  this  point  a  nearly- 
continuous  cutting  for  almost  a  mile  through  these  light-green,  quartzy 
sericite-schists,  here  -wholly  barren  and  monotonous. 

Just  beyond  the  fourth  bridge  many  beds  of  a  flat-fissile,  epidotic 

amphibolite  and  of  sericite-schist  are  exposed,  as  follows,  eastward  from  the 

bridge : 

Section  of  Bowe  sckist  containing  amphibolite. 

Feet. 

Sericite-schist 78 

Amphibolite 33 

Sericite-schist 23 

Amphibolite 3 

Sericite-schist 7 

Amphibolite 3 

Sericite-schist 30 

Amphibolite 150 

Sericite-schist 59 

The  same  rock  extends,  poorly  exposed,  with  a  single  small  band  of 
am.phibolite  to  the  Chester  amphibolite  at  the  Chester  line;  whole  thick- 
ness, 820  feet. 

This  is  the  first  case  where  any  amphibolite  occurs  below  the  Chester 
amphibolite,  and  it  is  here  that  the  remarkable  overfolding  or  overcrushing 
of  the  vertical  beds  of  thin-fissile  amphibolite  occur,  which  has  been  figured 
by  President  Hitchcock,  who  refers  it  to  crushing  by  ice.^ 

HAMPDEN    COUNTY. 

The  rock  is  best  studied  along  the  Chester-Becket  road,  westwai'd 
from  the  Chester  emery  mine,  where  miich  rock  cutting  has  been  done  to 
protect  the  highway  from  the  mountain  brook  along  which  it  runs.  It  is  a 
soft,  greasy  sericite-schist,  often  becoming  very  quartzose  and  then  of  firmer 
texture.  It  enters  the  Granville  quadrangle  (and  at  the  same  time  Hampden 
County)  at  its  northwest  corner,  and  continues  with  a  width  of  half  a  mile 
to  the  pond  at  North  Blandford.  Two  miles  farther  south,  as  noted  in  the 
description  of  the  Hoosac  schists,  the  whole  area  across  from  the  Becket 
gneiss  to  the  Chester  amphibolite  is  biotitic  and  feldspathic  and  not  marked 

'  Elementary  Geology,  p.  139. 


78        GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

by  liydrated  mica.     As  the  iuterveuing  area  is  almost  wholly  covered,  the 
line  is  drawn  upon  the  map  with  much  doubt. 

THICKNESS. 

The  section  gone  over  from  the  Middlefield  station  to  the  top  of  the 
series  at  the  Chester  line  is,  measured  directly  across  the  strike,  6,970  feet, 
which,  with  an  average  dip  of  nearly  80°,  would  give  a  thickness  for  the 
series  of  6,897  feet,  provided  there  be  no  repetitions  from  close  folding  or 
secondary  structure  simulating  bedding— a  thing  one  would  be  very  unwill- 
ing to  admit.  This  includes,  it  will  be  noticed,  the  two  beds  between  the 
Becket  gneiss  and  the  big  hornblende  bed;  that  is,  the  Hoosac  and  Rowe 
schists. 

THE   CHESTER  AMPHIBOLITE  AISTD  SERPEKTIKES. 

The  albitic  mica-schist  and  the  lower  sericite-schist  already  described, 
the  hornblendic  band  which  is  separately  discussed  in  this  chapter,  and  the 
upper  sericite-schist  and  the  chloritic  schist  next  to  be  treated  (that  is,  the 
Hoosac  schists  to  the  Hawley  schists,  inclusive)  are  certainly  one  conform- 
able series  of  beds,  and  form  a  group  well  demarcated  from  all  above  and 
below.  The  correlation  of  the  strata  has  been  attended  with  great  difficulty, 
owing  in  large  part  to  the  fact  that  southward  along  the  line  of  strike  the 
hydration  of  the  mica  becomes  less,  and  at  last  becomes  inappreciable,  while 
the  chlorite  also  disappears  and  the  feldspar  increases  in  quantity,  so  that 
what  in  Hampshire  County  is  well-characterized  hydi'omica  and  chloritic 
schist  becomes  in  Hampden  feldspathic  mica-schist,  or  even  quite  well- 
marked  gneiss.^ 

I  have  therefore  found  the  broad  band  of  amphibolite,  associated 
abundantly  with  serpentine  and  talc,  although  interrupted,  to  form  an 
exceedingly  useful  horizon  clear  across  the  State.  Carrying  as  it  does  the 
unique  emery  vein  at  Chester,  it  is  also  of  great  interest  in  itself. 

GENERAL    DESCRIPTION. 

The  amphibolite  is  a  dark-green  rock,  either  flat  thin-fissile  or  ligni- 
form,  and  rarely  massive.  It  is  almost  always  epidotic.  Along  its  eastern 
(that  is,  its  former  upper)  surface  at  various  points  occur  great  masses  of  ser- 
pentine or  serpentine  and  steatite  (the  latter  above  the  serpentine),  or  rarely 

•This  change  is  caused  by  the  great  quantity  of  granite  in  and  south  of  Blandford,  from  which 
the  schists  are  greatly  soaked  witli  feldspar. 


THE  CHESTER  AMPHIBOLITE  AND  SERPENTINES.  79 

of  steatite  alone.  These  lenticular  masses  have  eaten  their  way  into  the 
amphibolite  for  various  distances,  and  it  is  suggestive  that  they  always 
appear  along  the  upper  surface  of  the  amphibolite,  or  on  the  upper  surface 
of  separate  bands  where,  as  is  often  the  case,  the  latter  rock  does  not  occupy 
the  whole  space  assigned  to  it  on  the  map,  but  has  intercalated  subordinate 
layers  of  sericite-schist. 

The  Chester  emery  bed  occupies  the  same  position  along  the  eastern 
border  of  the  amphibolite.  The  character  of  the  serpentine  bands  which 
accompany  the  amphibolite  changes  in  Blandford.  At  Osborn's  quarry  is 
a  bed  of  sahlite-serpentine,  one  of  olivine-serpentine,  and  the  first  of  a 
series  of  enstatite-serpentines,  which,  as  the  bed  is  followed,  becomes  of 
greater  relative  importance  and  gradually  almost  replaces  the  amphibolite 
and  is  itself  at  last  almost  replaced  by  coarse  dolomitic  limestone. 

The  band  is  in  its  whole  extent  conformable  with  the  sericite-schists 
and  runs  across  the  country  with  dip  varying  very  little  from  90°  and  in 
strike  conforming  to  the  winding  of  the  schists. 

FRANKLIN  COUNTY. 

THE   ROWE   SERPENTINE. 

In  the  northern  portion  of  the  State  the  band  enters  the  town  of  Rowe 
from  Vermont,  exactly  at  its  northeast  corner,  and  extends  southwest  across 
the  town  as  a  heavy  bed,  1 0  to  20  rods  wide,  of  a  black,  thick-bedded,  epidotic 
amphibolite.  It  seems  to  be  continued  far  north  to  the  important  actinolite 
bed  at  Newfane.  It  is  well  exposed  at  the  bottom  of  the  hill  south  of  the 
house  of  J.  Streeter,  jr.,  and  runs  about  a  mile  west  of  Rowe  Center,  where, 
49  rods  northeast  of  A.  C.  Bliss's,  it  carries  on  its  east  border  a  heavy  bed  of 
steatite  (bed  No.  1^),  which  is  very  hard  and  chloritic.  From  this  point  it 
takes  the  same  curve  as  the  Deerfield  River  to  the  west,  and  forms  the  crest 
of  a  ridge  until,  at  J.  C.  Cressy's,  it  crosses  the  road  running  down  to  Hoosac 
Tunnel.  It  is  here  30  rods  wide,  is  very  fine-grained,  black  schist  in  its 
western  portion,  and  on  the  east  is  an  epidotic  quartz-hornblende-schist, 
and  there  are  one  or  two  other  bands  a  few  rods  east  in  the  hydromica- 
schist.  It  continues  down  the  hill,  and  where  it  cuts  across  a  sharp  bend 
in  the  road  it  changes  suddenly  almost  entirely  into  serpentine  and  steatite 
(bed  No.  2),  only  7  feet  of  the  amphibolite  remaining  on  the  western  border. 

1  For  convenience  of  reference  I  have  numbered  the  beds  of  steatite  and  serpentine  described  in 
this  section. 


Chester  amphibolite .  < 


80  GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

Here  the  following  section  is  exposed,  from  below  upward,  i.  e.,  from  west 

to  east: 

Section  at  Bowe  serpentine  quarry. 

Feet.  Inch. 

Rowe  schist 1.  Sericite-schist. 

r  2.  Hornblende-schist 7    0 

3.  Talcose  schist 0    1 

4.  Serpentine,   showing  structure  of 
amijhibolite 450    0 

5.  Talcose  schist 46    0 

v6.  Chlorite-schist 7    0 

Savoy  schist 7.  Sericite-schist.  

Total  thickness,  from  2  to  G  inclusive 510     1 

No.  4  is  a  serpentine  altered  from  amphibolite;  3  and  5  are  masses  of 
schistose  talc,  representing  a  further  stage  of  the  alteration.  It  abounds  in 
dolomite.  It  has  been  extensively  quarried,  but  the  large  buildings  erected 
for  working  it  are  abandoned. 

THE  BAST  PORTAL  FAULT. 

The  series  maintains  a  width  of  about  30  rods  down  to  a  point  100 
feet  above  the  Deerfield  River,  and  the  continuation  of  the  band  can  not 
be  found  across  the  river  on  the  south;  but  it  is  shifted  a  mile  to  the 
west,  to  Mount  Serpentine,  by  an  important  fault  running  in  the  bed  of 
the  "Westfield  River  at  this  point.  It  is  thus  carried  beyond  the  limit 
of  Franklin  County,  but  as  it  is  still  within  the  Hawley  quadrangle 
its  further  course  is  traced  to  the  point  where  it  enters  Worthington,  in 
Hampshire  County. 

The  steep  mountain  rising  west  of  Rice's  tavern,  at  the  east  portal 
of  Hoosac  Tunnel,  and  easily  distinguished  from  the  others  that  surround 
the  valley  by  its  bare  precipitous  walls,  is  Mount  Serpentine,  and  is  a 
great  mass  of  the  rock  which  has  given  it  its  name.  Its  north  face  seems 
to  be  the  face  of  the  fault  here  described;  its  east  wall  appears  to  be 
foi'medby  the  peeling  off  of  the  vertical  schist  from  the  massive  serpentine. 

The  mountains  as  seen  from  the  valley  are  projections  of  the  plateau, 
notched  by  the  successive  brook  gorges;  and  taking  the  road  running  up 
southwest  from  Rice's  tavern,  one  finds  at  the  first  brook-crossing  a 
magnificent  bowlder  of  serpentine,  and  can  climb  by  this  brook  to  the 
serpentine  overhead.  By  following  the  road  to  the  first  house,  and  then 
going  50  rods  west,  one  comes  on  the  serpentine,  after  passing  a  band  of 


TUB  CHESTER  AMPHIBOLITE  AND  SERPENTINES.  81 

amphibolite  6  rods  wide  and  10  rods  of  swampy  ground,  probably  in 
whole  or  part  underlain  by  steatite  (bed  No.  3).  Then  comes  tlie  dark- 
green  serpentine,  which  is  here  35  rods  wide,  and  it  is  followed  immedi- 
ately by  black,  thin-fissile  amphibolite.  This  is  so  clearly  a  repetition  of 
the  series  at  the  soapstone  quarry  given  above  that  a  fault,  substantially 
as  shown  on  the  map,  is  quite  certainly  present. 

Where  the  beds  cross  the  road  to  the  south  they  are  covered,  and 
continue  so  as  far  south  as  I  could  penetrate  in  this  wilderness. 

At  latitude  42°  35§',  longitude  72°  55f' ,  the  amphibolite  appears  again, 
and  the  line  of  boundary  is  drawn  approximately  from  the  strike  between 
these  points,  as  the  amphibolite  could  not  be  found  and  the  sericite-schists 
above  and  below  the  amphibolite  are  hardly  distinguishable.  Indeed,  at 
the  cross-roads  a  mile  north  of  the  last  locality  the  sericite-schist  is 
almost  continuously  exposed,  but  careful  search  failed  to  disclose  any 
amphibolite. 

From  the  last  locality  the  amphibolite  makes  a  bend  to  the  east  and 
cuts  across  the  sharp  curve  in  the  road  next  south.  On  entering  the 
Chesterfield  quadrangle,  the  amphibolite,  where  it  crosses  the  road  near 
Swift  River,  in  Windsor,  is  changed  to  steatite  (bed  No.  4),  and  at  Jordans- 
ville  the  schist  is  well  exposed  in  the  brook  southwest  of  the  village. 

HAMPSHIRE   COUNTY. 
THE   MIDDLBFIEUD   SERPENTINE. 

Reentering  the  county,  the  amphibolite  appears  just  west  of  the  village 
of  West  Worthington,  and  can  be  traced  thence  southward.  At  H.  Smith's, 
in  the  northwest  of  Middlefield,  it  has  on  the  east  a  fine  deposit  of  serpen- 
tine (bed  No.  5),  bordered  on  the  east  by  talc.  Along  the  east  side  of  a 
band  of  the  common  amphibolite  rests  a  mass  of  dark-green  serpentine,  and 
next  east  a  great  mass  of  steatite,  often  carrying  large  nodules  of  the  finest 
dolomite  surrounded  by  delicate-green  talc,  and  on  the  east  sericite-schist 
folds  around  the  great  boss  of  steatite,  as  if  it  had  been  present — or,  rather, 
as  if  the  rock  of  which  it  has  been  formed  had  been  present — as  a  foreign 
and  resistant  body  during  the  compression  of  the  schists.  The  steatite  is 
here  QQ  feet  wide,  and  it  furnishes  the  best  material  in  its  upper  half  It 
is  opened  in  a  quarry  41  feet  wide  and  82  feet  long,  and  is  separated  from 
the  amphibolite  opposite  the  quany  by  only  16  feet  of  covered  space;  so 
MON  XXIX (I  ■ 


82        GEOLOGY  OP  OLD  HAMPSHIEE  COUNTY,  MASS. 

here  the  seipeutine  can  have  at  most  only  this  thickness,  though  it  swells  a 
few  yards  north  to  treble  this  thickness  at  the  expense  of  the  steatite, 
which  runs  on  north  for  a  distance  of  492  feet,  with  a  thickness  of  10  feet, 
and  enlarges  again  into  a  pocket  of  harder  soapstone. 

The  deposit  extends  southward  across  the  road,  and  is  then  opened  again 
in  a  large  quarry  on  the  land  of  Mr.  Howard.  The  New  York  Metropolitan 
Company  has  quarried  200  tons,  paying  a  royalty  of  50  cents  a  ton,  and  the 
material  was  ground  at  a  mill  in  the  valley  to  the  east.  About  as  much 
more  had  been  gotten  out  earlier,  but  no  work  was  in  progress  at  the  time 
of  my  visit  (1877).  This  is  a  type  of  all  the  serpentine  and  talc  deposits — 
a  lenticular  mass  of  serpentine  replacing  the  amphibolite  in  its  upper 
layers,  and,  as  it  were,  eating  into  its  mass  and  suggesting  strongly  that  it 
has  been  formed  at  the  expense  of  the  schist  and  itself  changed  later  for 
a  varying  distance  downward  into  talc. 

In  a  recent  interview  published  in  the  Springfield  Republican,^  the 
discovery  by  Dr.  H.  S.  Lucas  of  another  bed  of  emery,  or  the  continuation 
to  the  north  of  the  Chester  bed,  is  announced.  It  is  at  a  point  a  mile  east 
of  Middlefield  and  a  mile  and  a  half  nearly  due  north  of  Chester,  on  land  of 
Frank  Smith,  and  the  land  has  been  purchased  by  Dr.  Lucas.  It  is  asso- 
ciated with  hornblende-schist,  as  is  the  Chester  bed,  and  is  quite  certainly 
the  continuation  of  this  bed  northward.  The  specimens  from  the  new 
locality  shown  me  by  Dr.  Lucas  contain  grains  of  blue  corundum. 

Southward  on  the  strike  the  outcrops  are  not  abundant,  but  they 
are  sufficient  to  show  that  the  amphibolite  is  probably  interrupted  for  a 
considerable  distance,  though  it  may  be  continued  as  a  narrow  band,  some- 
what shifted  by  faults.  Two  miles  southeast  of  the  cheese  factory  it  appears 
again  in  great  force,  and  immediately  to  the  east  of  it  the  serpentine  (bed 
No.  6)  appears  in  still  greater  force.  The  two  expand  rapidly  to  a  width 
of  200  rods  and  run  as  a  prominent  range  of  hills  over  the  town  line  into 
Chester,  dropping  down  suddenly  to  the  brink  of  the  Westfield  River.  On 
the  east  and  west  the  vertical  sericite-schists,  200  rods  apart,  inclose  this 
great  double  bed  of  amphibolite  and  serpentine,  and  are  continuous  across 
the  river  to  the  south,  and  the  western  half  of  the  bed,  the  amphibolite,  also 
continues  across,  its  eastern  half,  the  serpentine,  being  replaced  by  amphib- 
olite in  the  bed  of  the  river.     The  boundary  between  the  two,  which  may 

1  "Another  vein  of  corundum:"  Springfield  Republican,  December  12,  1895. 


THE  CHESTER  AMPHIBOLITE  AND  SERPENTINES.  83 

be  found  just  opposite  a  shoddy  mill  near  the  river,  runs  in  a  great  curve 
N.  30°  W.,  so  that  the  serpentine  encroaches  still  more  on  the  amphibolite 
and  at  last  occupies  nearly  its  whole  width.  An  inspection  of  the  map 
(PI.  XXXIV)  shows  that  the  course  of  the  river,  where  it  separates  ser- 
jjentine  and  amphibolite,  is  in  southward  continuation  of  this  curve,  and 
that  the  serpentine  is  lodged  as  a  great  lens,  a  mile  and  a  half  long  and 
nearly  a  half  mile  wide,  in  the  amphibolite.  The  boundary  line  between 
the  two  runs  up  the  hillside  in  a  narrow  gorge,  its  bottom  everywhere 
encumbered  with  bowlders,  and  the  amphibolite  and  serpentine  could  not 
be  found  nearer  each  other  than  10  feet.  At  that  distance  there  was  no 
trace  of  transition  from  one  into  the  other.  Search  was  made  for  the  bound- 
ary between  the  serpentine  and  the  sericite-schist  on  the  east  for  a  mile 
north  through  the  dense  woods,  but  they  could  not  anywhere  be  found  in 
actual  contact.  The  contact  line  was,  however,  a  straight  one,  following 
the  line  of  strike  of  the  schist,  while  the  schist,  ordinarily  a  very  flat-fissile 
rock,  was  for  all  this  distance,  and,  indeed,  for  the  full  length  of  the  ser- 
pentine lens,  and  in  a  thickness  of  above  350  feet,  thrown  into  the  most 
extreme  contortions  and  twistings,  the  like  of  which  I  have  hardly  seen 
among  any  of  the  rocks  of  the  region.  This  I  take  to  be  another  indication 
of  the  formation  of  the  serpentine  before  the  final  folding  of  the  region. 
It  is  likewise  interesting  that  along  this  line  the  serpentine  was  in  many 
places,  and  it  seemed  continuously,  separated  from  the  sericite-schists 
above  by  a  thin  layer  of  amphibolite,  and  the  serpentine,  when  traced  to 
within  a  single  foot  of  this,  was  complete  serpentine.  The  mass  of  the  latter 
would  seem  to  be,  then,  strictly  speaking,  inclosed  in  the  amphibolite. 

As  already  noted  by  President  Hitchcock,  this  serpentine  mass  shows 
abundant  signs  of  stratification,  and  I  may  add  that  this  not  only  agrees 
with  the  dip  and  strike  of  the  adjoining  amphibolite,  but  shows  closer  agree- 
ment still  with  the  latter,  extending  to  the  exact  thickness  of  the  laminae, 
the  angles  and  distance  of  the  jointing,  etc.;  and  further,  that  this  structure 
is  one  brought  out  in  the  serpentine  again  only  by  the  action  of  atmospheric 
agents,  below  the  surface  the  serpentine  appearing  wholly  compact.  The 
serpentine  is  the  common  rather  light  oil-green  variety,  and,  especially 
where  a  fine  splintery  fracture  is  developed,  it  has  a  dry  grayish-green 
color.  It  weathers  to  a  deep  red  brown,  and  the  great  ragged  hill,  bare  of 
vegetation  and  covered  with  an  almost  unbroken  layer  of  immense  bowlders 


84        GEOLOGY  OP  OLD  HAMPSHIRE  COUNTY,  MASS. 

upheaved  by  frost,  is  a  very  striking  object,  suggesting  immediately  the 
idea  of  igneous  action. 

I  visited  the  place  once  when,  after  heavy  rains,  the  fine  brook  which 
runs  down  from  the  high  ground  in  a  great  gorge  lined  with  bowlders  of 
the  weathered  serpentine,  and  the  succession  of  beautiful  waterfalls,  derived 
a  peculiar  charm  from  their  setting  in  the  warm  browns  and  greens  of  the 
rugged  serpentine  masses. 

The  serpentine  locally  is  rich  in  chromite,  and  a  considerable  excava- 
tion made  in  mining  for  it  exists  in  the  woods  near  the  southeast  extremity 
of  the  bed.  Small  veins  of  precious  serpentine,  much  picrolite,  and  crusts  of 
hydromagnesite  of  some  thickness  occur.  It  also  furnished  to  Dr.  Emmons 
the  well-known  pseudomorphs  of  serpentine  after  chrysolite,  formerly  called 
serpentine  after  quartz,  or  hampshirite,  the  exact  locality  of  which  I  have  not 
been  able  to  recover,^  and  was  doubtless  the  origin  of  the  large  masses  of 
yellow  chalcedony  found  in  Chester  by  the  same  geologist.  These  pseudo- 
morphs are  large,  distinct  crystals  more  than  an  inch  long.  They  are  six- 
sided  prisms  terminated  by  six  faces  which  have  some  resemblance  to  the 
ending  of  a  quartz  crystal,  in  which  two  opposite  faces  predominate,  but 
giving  the  angles  of  chrysolite.  They  are  covered  by  a  straw-yellow, 
secondary  serpentine  of  a  compact  but  slightly  radiate-fibrous  structure 
(picrosmine) ;  it  is  homogeneous  and  almost  apolar  under  the  microscope. 
An  analysis  was  made  for  me  by  Miss  Helen  P.  Cook,  of  the  chemical 
department  in  Smith  College. 

Analysis  of  pseudomorphs  of  serpentine. 


SiOo 

MgO 

Fe^Ci  [AI2O3  trace] 

Ignition,  6^  hours,  55°  to  150°  C. 
Ignition,  open  flame  and  blast . . 


Per  cent. 

40.27 

40.00 
4.74 
0.92 

13.38 


99.31 


Secondary  shrinkage  joints  in  serpentine. — The  detached  blocks  of  the 
serpentine  have  often  suffered  secondary  decomposition,  so  common  with 

1  These  are  fully  described  and  figured,  and  the  proof  of  their  derivation  from  chrysolite  is  given,  in 
A  mineralogical  lexicon:  Bull.  U.  S.  Gaol.  Survey  No.  126, 1895,  pp.  92,  146,  under  "Hampshirite." 


THE  CHESTER  AMPHIBOLITE  AND  SERPENTINES,  85 

serpentine,  to  a  depth  of  10-15""°,  accompanied  with  loss  of  color,  hardness, 
and  volume;  and  as  a  result  of  this  last  the  surface  is  often  covered  with 
a  tine  system  of  regular  slirinkag-e  joints,  one  set  of  straight  fissures  about 
20"'"'  apart  being  cut  by  another  at  an  oblique  angle,  the  latter  about 
50""°  apart.  In  places  the  blocks  have  all  separated  from  the  underlying 
unchanged  mass  and  lie  loosely  upon  it. 

HAMPDEN    COUNTY. 

THE   CHESTER  AMPHIBOLITE   AND   SERPENTINE. 

Following  the  heavy  hornblende  band  across  Chester,  where  it  forms 
in  the  north  the  high,  sharp  ridge  called  Gobble  Mountain,  and  in  the  south 
the  still  higher  Round  Mountain,  one  finds  in  the  higher  part  of  the  first 
hill  a  considerable  deposit  of  serpentine  (bed  No.  7),  situated,  like  the  others, 
at  the  upper  surface  of  the  hornblende,  but  offering  nothing  peculiar. 
Farther  south,  in  the  bottom'  of  the  brook  gorge  between  these  hills,  at 
the  old  emery  mine,  is  another  deposit  (bed  No.  8),  which  is  at  a  level  of 
several  hundred  feet  below  the  other. 

The  excavations  at  the  mine  exposed  the  following  section  from  east  to 
west  across  the  vertical  strata: 

Section  at  the  old  emery  mine  near  Chester. 
Savoy  acMst Sericite-schist. 

Feet. 

'Steatite  inclosing  a  few  small  serpen- 
tine nodules 4-16 

Emery  and  magnetite  bed 6J-10 

Fringe  rock 1  inch  to  10 

.  Hornblende-schist. 


Chester  amphibolite . .  < 


The  small  nodules  of  serpentine,  often  as  large  as  one's  hand,  are 
isolated  in  the  mass  of  the  talc  and  are  permeated  by  veins  of  the  same 
material,  and  doubtless  represent  the  original  material  from  which  the  talc 
was  formed.  The  serpentine  is  the  usual  variety,  dark-green  when  wet, 
but,  partly  from  its  fine  splintery  fracture,  gray-green  when  dry.  Another 
variety  is  rich  olive-green,  and  carries  much  malachite. 

The  talc  is  pale-green,  foliated  for  the  most  part,  and  often  crowded 
with  dolomite  crystals. 

THE    BLANDFORD    SERPENTINES   AND   PYKOXBNITE. 

The  heavy  hornblende  bed  continues  with  undiminished  width  across 
Chester,  and  is  much  covered  by  drift  as  it  crosses  into  Blandford,  where  it  is 


86        GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

again  well  exposed.  Northwest  of  S.  A.  Bartholomew's  house,  at  his  soap- 
stone  quaiTy,  some  layers  of  mica-schist  are  intercalated  in  the  amphibolite. 
The  quany,  from  which  much  soapstone  (bed  No.  9 )  has  been  taken  for  grind- 
ing, is  inclosed  in  walls  of  chloritic  mica-schist,  and  lies  in  the  prolongation  of 
a  bed  of  the  ordinary  amphibolite,  which  is  exposed  just  north  of  the  opening. 

There  is  exposed  in  the  north  end  of  the  excavation  a  layer,  1  foot 
thick,  of  light-green  talc  with  scattered  needles  of  actinolite,  and  east  of 
this,  one  (the  same  thickness)  of  a  green,  soft,  scaly  chlorite,  with  here  and 
there  larger  jjlates  of  clinochlore  with  very  divergent  optical  axes,  and 
magnetite  octahedra.  Farther  south,  in  the  bottom  of  the  quarry,  it  can 
be  seen  that  the  steatite  bed  widens  rapidly  southward  to  10  feet,  and  a  mass 
of  light-green  fibrous  actinolite  appears,  from  which  the  whole  steatite  mass 
seems  to  have  been  derived,  as  it  still  retains  the  radiated  and  matted 
acicular  structure  of  the  actinolite. 

A  few  rods  south  of  the  steatite  quarry,  and  just  west  of  the  village  of 
North  Blandford,  is  the  great  mass  of  serpentine  (bed  No.  10)  marked 
upon  Walling's  map  of  the  county  as  "The  Crater."  The  name  is  said  to 
have  originated  with  Dr.  Hitchcock,  when  he  thought  the  rounded,  isolated 
mass,  with  a  large  cavity  in  its  center,  proof  of  the  volcanic  origin  of  ser- 
pentine. It  seems  to  me  not  improbable  that  the  cavity  in  question  may  be 
an  artificial  excavation,  and  it  is  certain  that  in  early  times  considerable 
digging  was  done  there  for  chromite.  It  is  an  oval  mass,  328  feet  long  and 
200  feet  wide.  On  the  west  is  a  stratum  of  amphibolite  20  feet  thick,  which 
strikes  north-south  along  the  side  and  wraps  round  the  north  end  until  it 
strikes  N.  28°  E.  This  seems  to  indicate  that  the  change  to  serpentine  took 
place  before  the  final  compression  of  the  rock,  or  that  the  original  rock  was 
different  and  less  compressible  than  the  amphibolite.  Below  is  the  sericite- 
schist.  The  serpentine  from  this  locality  is  easily  distinguished  from  any 
other  by  its  compactness,  its  black-gray  color,  the  abundance  of  dissemi- 
nated magnetite,  and  the  nickel-green  crust  from  weathering. 

Along  the  strike  of  the  rocks  southeast  by  south  the  ground  is  much 
covered  and  no  further  outcrops  have  been  found,  though  the  region  has 
been  thoroughly  searched  in  prospecting  for  emery,  until  the  Osborn  soap- 
stone  quarry  is  reached;  but  several  bowlders  reported  to  me  by  Mr. 
Bartholomew,  viz,  serpentine  west  of  the  north  end  of  Blair's  pond,  and 
soapstone  northwest  of  Pebble's  brook,  and  also  west  of  the  Blair's  pond 
road,  indicate  other  deposits  in  the  intervening  space. 


THE  CHESTER  AMPHIBOLITE  AND  SERPENTINES.  87 

The  Osborn  soapstoue  quarry  lies  west  of  the  house  of  Mr.  W.  H. 
Griswold.  Passing  west  over  a  few  rods  of  sericite-schist,  with  two  granite 
dikes  and  a  thick  stratum  of  serj^entine,  and  more  schist,  all  with  strike 
N.  40°  W.,  dip  46°  E.,  one  comes  upon  a  bed  (No.  11)  of  black  serpentine 
50  feet  thick,  which  can  be  followed  south  a  considerable  distance  along 
the  line  of  strike  and  ends  abruptly  against  chlorite-schist  along  a  line  at 
right  angles  to  the  strike. 

It  is  also  underlain  by  the  chlorite-schist,  and  following  the  line  of 
strike  of  this  south  a  few  yards,  across  covered  ground,  one  comes  upon  the 
large  quarries  of  a  soapstone  which  has  completely  the  structure  of  the 
coarse  radiated  actinolite  from  which  it  has  been  derived,  and  fresh  and 
partly  altered  masses  of  the  latter  are  also  abundant,  together  with  large 


^„C-^^ 


N  ■*0°W  fS'E 


N  35  °W  80°£ 


N35°tV'*5''E 


riG.  S.-Section  at  Osborn  soapstone  quarry,  Blandford.     S  S  =  Salilit6-serpentine;   S  =  Steatite  and  enstatite-serpen- 
tme;  0S  =  01ivine-serpentine;  A  =  Amphibolite ;  P  =  Pegmatite;  conntiy  rook  =  sericite-schist. 

masses  of  coarsely  foliated  chlorite — a  clinochlore  with  very  wide  optical 
angle.  The  steatite  bed  is  separated  by  a  thin  stratum  (1  inch)  of  black 
mica  and  ©ne  of  equal  thickness  of  heavy  black  hornblende-magnetite  rock 
from  a  dike  of  granite. 

A  small  brook  runs  from  this  point  west  through  the  woods,  down  over 
sericite-schist,  to  the  bottom  of  the  valley,  where  it  cuts  a  great  bed  of 
pecuhar,  streaky,  black  to  gray  serpentine  (SS;  bed  No.  12),  derived  from 
a  very  coarse-grained  pyroxenite  or  sahlite  rock,  which  still  shows  cleavage 
faces  20-30 """^  square.  This  bed  seems  to  haA^e  been  overlooked  before, 
and  it  is  doubtless  the  source  of  many  of  the  bowlders  found  in  the  south- 
eastern part  of  the  town. 

The  old  quarry  has  been  opened  during  the  past  summer  (1895)  quite 
extensively  with  improved  machinery.     The  whole  width  of  the  steatite 


88 


GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 


bed  lias  been  exposed  and  a  deep  trench  blasted  through  the  schists  to  the 
west  for  drainage.  The  following  section  is  now  exposed  (fig.  5,  p.  87): 
Commencing  at  the  bottom  of  the  hill  to  the  west,  one  climbs  up  15  rods 
over  coarse  chloritic  sericite-schists  abounding  in  large  quartz  lenses  and 
quartz-filled  garnets  sometimes  an  inch  across.  The  schists  dip  80°  E. 
At  50  feet  above  the  meadow  the  lower  bed  of  coarse,  rudely  bedded,  black 
serpentinous  rock  appears  (SS).  It  shows  broad,  black,  lustrous  cleavage 
surfaces  of  much-altered  sahlite,  and  no  specimens  could  be  found  where 
this  mineral  was  still  unchanged,  such  as  were  procured  in  the  bed  of  the 
brook  at  the  former  visit.  These  cleavage  surfaces  make  up  the  whole 
surface,  or  are  somewhat  separated  and  the  interstices  filled  with  white 
calcite  and  magnetite  and  shot  through  with  tremohte. 

An  analysis  of  the  least-altered  forms  of  this  rock,  which  still  retains 
enough  of  the  unaltered  sahlite  to  enable  one  to  make  out  its  optical  con- 
stants, gives  the  complete  formula  of  serpentine,  and  is  interesting  as  show- 
ing, as  do  all  the  other  rocks  of  the  series,  a  constant  content  of  nickel  and 
chromium.     The  analysis  was  made  by  Dr.  W.  F.  Hillebrand. 

Analysis  of  serpentine  from  Osborn's  soapstone  quarry,  Blandford,  Massachusetts. 


SiO.2 

TiOi 

Al.Oa 

CroOs 

Fe^Os 

FeO 

NiO 

MnO 

CaO 

SrO 

BaO 

MgO 

K3O 

NajO 

Li,0 

HjO  below  110° 
H2O  above  110° 

PsOs 

CO2 


Per  cent. 

40.77 

None. 

1.16 

.      .28 

3.56 

1.47 

.17 

^.09 

None. 

None. 

None. 

39.37 

.10 

.14 

Trace. 

.49 

12.48 

Trace. 

None. 

100. 08 


THE  CHESTER  AMPHIBOLITE  AND  SERPENTINES.  89 

Next  east  is  a  bed,  150  feet  thick,  of  finer-grained  chloritic  sericite- 
schist,  without  garnets,  and  containing  a  subordinate  bed  of  jet-bUxck,  flat- 
bedded  amjjhibohte  (A),  which  is  made  up  almost  wholly  of  shining-black 
needles,  the  larger  porphyritic  in  a  network  of  the  smaller.  Eight  feet  of 
coarse  pegmatite  are  followed  by  the  same  thickness  of  schist,  and  this  by 
12  feet  of  pegmatite,  which  is  separated  by  a  thin  layer  of  reddish  schist 
from  the  soapstone  (S),  which  is  60  feet  thick.  On  the  west  border  is  a 
thick  bed  of  coarse  tourmaline  in  a  matted  mass  of  large  clinochlore,  with  a 
6-inch  bed  of  coarse  biotite  adjacent.  The  eastern  selvage  is  of  coarse 
transverse  chlorite  in  broad  plates,  which  is  often  crushed  to  schist. 

The  outer  sheets  of  the  main  soapstone  bed  are  of  coarse,  matted  trem- 
olite,  often  radiated  and  plumose,  and  more  or  less  changed  to  talc.  In  the 
eastern  portion  of  the  soapstone  bed  is  a  10-inch  layer  of  fine  actinolite,  and 
at  the  border  these  actinolite  needles  change  directly  into  tremolite. 

The  central  third  of  the  steatite  bed  consists  of  black  enstatite- 
serpentine,  more  or  less  tremolitic  and  partly  changed  to  steatite,  but  still 
quite  hard.  This  is  the  first  bed  of  this  enstatite  rock  met  with,  and  it 
becomes  increasingly  important  as  the  series  is  traced  southward.  Layers 
of  an  apple-green  serpentine  fill  fissures  in  this  mass.  The  superintendent 
informed  me  that  a  2-foot  layer  of  a  black  amphibolite,  exactly  like  that 
descnbed  above,  ran  through  the  soapstone  parallel  with  the  strike  in  a  part 
of  the  quarry  which  was  under  water.  The  vein  of  steatite  makes  a  sharp 
bend  of  90°  to  the  east,  and  bends  directly  back  90°  to  the  north,  and 
along  the  east  side,  where  the  latter  bend  is  effected,  the  eastern  schist 
wraps  irregularly  over  the  steatite  and  around  a  white  albite  lens,  which  is 
enclosed  in  a  thin  layer  of  black,  coarse  hornblende  rock.  This  bend 
explains  the  cutting  off  of  the  bed  of  black  serpentine  mentioned  above, 
and  shows  that  beyond  this  sudden  fault-like  bend  the  band  is  less  altered 
to  steatite.  Indeed,  the  steatitic  alterations  may  be  due  to  local  disturb- 
ance, as  the  development  of  serpentine  farther  north  seems  to  be  caused 
by  faults. 

The  next  eastern  bed  is  a  reddish,  quartzose,  fine-grained  biotite-schist 
150  feet  thick.  This  is  followed  up  the  hillside  by  150  feet  of  a  massive,  dark- 
green  serpentine  (OS),  which  at  the  base  shows  much  half-changed  olivine  in 
granular  masses,  separated  by  a  later  tremolitic  growth,  followed  by  talc, 
all  of  which  is  beautifully  shown  under  the  microscope.     This  is  the  only 


90        GEOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 

trace  of  olivine  that  has  been  found  west  of  the  river,  except  the  Middlefield 
pseudomorphs  mentioned  above. 

A  bed  of  pegmatite  a  rod  wide  separates  the  serpentine  from  schist, 
wliich  continues  up  the  hill  412  feet  to  the  Grriswold  house. 

THE   GRANVILLE  AND   RUSSELL  ENSTATITE- SERPENTINES. 

From  the  section  north  of  Borden  Brook,  in  the  south  of  Blandford, 
where  the  hornblendic  complex  is  made  up  of  several  amphibolite  beds 
alternating  with  beds  of  sericite-schist,  the  series  continues  due  south  into 
Grranville,  and  is  for  a  short  distance  interrupted  by  pegmatite,  but  attains 
in  Liberty  Hill  a  thickness  of  1,237  feet  of  clear,  black  amphibolite  without 
interlaminated  mica  beds.  It  curves  east  and  then  west  and  retains  this 
great  width  for  a  mile,  and  continues  southwest  as  two  bands  of  amphibo- 
lite, each  about  15  feet  wide.  These  soon  run  out  southward,  and  no  trace 
of  them  could  be  found  in  the  well-exposed  bluffs  east  of  West  Hartland. 
Where  it  bends  most  easterly  it  contains  the  heavy  bed  of  steatite  (bed 
No.  13)  a  mile  southwest  of  West  Granville,  at  the  bottom  of  the  bluff  east 
of  E.  Williams's  house.  Here  some  work  has  been  done  upon  a  deposit 
of  steatite,  which  has  been  derived  from  a  bed  of  fine,  radiated  tremolite; 
it  still  retains  the  structure,  and  part  of  it  the  hardness,  of  hornblende,  and 
therefore  the  bed  is  not  a  promising  one  to  work.  Many  bowlders  of 
the  black  enstatite-serpentine  occur  near  Mr.  Williams's  house,  which  must 
come  from  another  bed  of  the  rock  near  at  hand,  as  the  two  rocks  seem  to 
be  connected  genetically,  since  the  tremolite  is  exactly  like  that  found 
with  the  serpentine  of  the  next  locality.  Just  after  crossing-  the  State  line 
and  Hubbard  Brook  the  amphibolite  band  carries  a  bed  of  black  enstatite- 
serpentine  (bed  No.  14),  of  which  about  5  or  6  feet  is  exposed. 

On  the  southeast  flank  of  Liberty  Hill,  in  West  Granville,  a  branch  of  the 
amphibolite  separates  from  the  main  bed,  as  mentioned  above,  and,  bending 
round  sharply,  runs  north  with  much  diminished  thickness,  not  exceeding 
6  feet,  to  a  point  west  of  East  Granville,  where  it  bends  noii;h  again  and 
carries  the  remarkable  bed  of  enstatite-serpentine  (bed  No.  16)  which  occurs 
in  a  densely  wooded  swamp  100  rods  east  of  the  house  of  J.  Downey.  A 
ridge  20  feet  wide  and  rising  24  feet  is  exposed  for  a  considerable  distance, 
and,  as  usual,  the  serpentine  is  associated  with  amphibolite.  It  is  a  black 
serpentine,  made  up  of  crystals  an  inch  square  on  the  end  and  more  than  2 


THE  CHESTER  AMrHlJ50LlTE  AND  SEKPENTmES.  91 

inches  long,  pseudomorph  after  enstatite,  and  it  carries  considerable  dolomite 
disseminated,  which  does  not  effervesce  with  HCl.  Traced  northward  a  few 
rods  it  becomes  a  compact,  gray,  thin-bedded  tremolite-schist,  which  lies  in 
contact  with  an  equally  thin-bedded,  white  crystalline  limestone  which 
eifei-vesces  readily.  Southward  it  is  found  in  many  bowlders  around  the 
cemetery,  and  here  the  limestone  contains  very  fine  specimens  of  a  rich- 
green  actinolite,  and  it  crops  out  farther  south  on  Trumble  Brook.  The 
band  can  be  traced  north  from  Downey's,  by  the  abundant  bowlders  of  the 
black  serpentine,  to  the  pasture  back  of  H.  Cooley's.  The  overljnng  rock 
in  the  Cooley  pasture  is  a  coarse  muscovite-biotite-schist,  carrying  much 
cyanite  in  flat,  colorless  blades  1  to  1 J  inches  long,  but  20  feet  of  covered 
space,  possibly  occupied  by  amphibolite,  separates  it  from  the  serpentine. 
The  serpentine  bed  (bed  No.  16)  is  about  50  feet  thick,  and  is  exposed  175 
feet  in  length.  Over  the  weathered  surfaces  of  the  ledge  the  great  enstatite 
crystals  project  in  a  close  network.  These  crystals  are  great  plates  one- 
half  to  1  inch  in  thickness,  3  to  4  inches  wide,  and  in  average  6  inches 
long,  while  some  measure  14  inches  in  length.  They  are  now  changed  to 
a  dull-black  serpentine,  but  still  retain  the  lustrous  enstatite  cleavage.  In 
the  naiTow  meshes  between  these  large  plates  is  a  rather  coarse-granular, 
limpid  dolomite,  dusted  with  small  magnetite  octahedra  and  broad  plates 
of  colorless  to  oil-green  talc.  The  band  can  be  traced  northwest  from  this 
point  by  many  large  bowlders,  and  another  locality  occurs  where  the  rock 
appears  in  place  southwest  of  the  point  where  "Wildcat  road"  bends  south. 
Bowlders  of  the  same  rock  occur  northwest,  in  the  bed  of  the  Westfield 
Little  River,  at  the  great  bend  a  mile  below  "Pothole  Rock."  From  this 
point  no  traces  of  the  bed  have  been  found  along  the  line  of  boundary 
drawn  across  Russell  to  the  Atwater  ledge,  except  where  this  line  crosses  a 
little-used  road,  not  on  the  map,  which  runs  west  from  the  sharp  bend  in  the 
road  a  mile  above  Atwater's  to  meet  the  dotted  road.  Careful  search  has 
been  made  in  the  intervening,  heavily  wooded  country,  and  the  presence  of 
the  rock  as  a  continuous  band  is  indicated  by  the  abundant  large  bowlders 
strewn  over  the  country  for  miles  southeast.  The  next  outcrop  is  the  one 
mentioned  above  as  Atwater's  (bed  No.  17),  from  the  extensive  exposure  in 
the  high  hill  1  mile  N.  30°  W.  of  the  house  of  F.  B.  Atwater,  in  the  south 
corner  of  Russell  and  overlooking  the  Westfield  plain.  It  was  quarried 
quite  extensively  by  Mr.  Atwater's  father  as  "black  marble."     The  bed  is 


92        GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

exposed  with  a  width  of  about  53  feet,  when  it  is  cut  off  by  granite.  It 
shows  distinct  foHation,  and  is  bordered  on  the  west  by  a  biotite-hornblende- 
schist,  which  becomes  in  places  a  distinct  gneiss.  It  is  a  black  serpentine 
abounding  in  the  green  foliated  bastite  to  which  the  name  marmolite  has 
been  given. 

THK   WESTFIELD   SERPENTINE  AND   MARBLE. 

The  next  outcrop  of  the  serpentine  is  south  of  this  point,  across  the 
Little  River,  in  the  western  edge  of  Westfield  (bed  No.  18).  It  has  been 
opened  by  the  owners,  the  Westfield  Marble  and  Sandstone  Company,  and 
reported  upon  during  the  last  year  (1895)  by  Prof  W.  0.  Crosby,  who 
considers  the  deposit  valuable  for  verd-antique  marble.  He  reports  the 
following  section  from  east  to  west,  with  explanations: 

Section  in  the  loestern  edge  of  WestfieM. 

Feet. 

1.  Yein  of  coarse  granite  (pegmatite) 10 

2.  Soapstone  and  serpentine,  with  partings  of  micascbist 

and  veins  of  pegmatite 15  to  20 

3.  Massive  serpentinic  marble  (verd  antique),  with   large 

crystals 15  to  20 

4.  White  marble,  with  thin  layers  or  partings  of  serpentinic 

marble 15 

5.  Banded  serpentinic  marble,  consisting  of  very  thin  alter- 

nating layers  of  white  marble  and  serpentine 15  to  20 

6.  Shaly  serpentine  and  marble  and  banded  serpentinic 

marble 20 

7.  Massive  black  and  green  serpentine 50 

8.  Soapstone  and  serpentine,  concealed- 10 

9.  Fibrolitic  ^  mica- schist  and  granite trace. 

The  most  interesting  and  valuable  bed  in  this  series  is  the  verdantique  marble 
(ISTo.  3).  This  is  a  very  solid  bed,  and  of  fairly  uniform  character,  considering  the 
coarse  structure  of  the  marble.  The  serpentine,  which  has  evidently  resulted  from 
the  alteration  of  actinolite,  is  in  the  form  of  slender  crystals  from  1  to  3  inches  in 
length,  lying  at  all  angles  in  a  matrix  of  white  crystalline  limestone.  Near  the  east 
side  of  the  bed  the  structure  is  finer  and  somewhat  banded,  as  in  bed  No.  5.  This 
verd-antique  marble  is  a  striking  and,  so  far  as  I  know,  unique  stone,  of  ornamental 
character;  and  I  can  see  no  reason  why  it  should  not  give  satisfaction  in  use. 
Although  it  would,  I  am  confident,  prove  serviceable  in  exterior  work,  it  is  to  be 
especially  recommended  for  interior  work.  It  is  susceptible  of  a  good  and  lasting 
polish,  and  this,  together  with  its  unique,  breccia-like  structure,  should  insure  a 
demand  for  the  stone  when  it  is  properly  brought  before  the  public.    It  is  probable 

'  This  is  oyanite. 


THE  CUESTER  AMPHIBOLITE  AND  SERPENTINES.  93 

that  at  a  somewhat  greater  depth  bed  No.  4,  which  coukl  be  very  easily  worked  with 
No  3  wou  d  yield  so,„e  good  white  marble.  A  part  of  the  banded  marble  iu  beds  5 
and  6  IS  of  a  decidedly  ornamental  character  and  well  adapted  for  some  kinds  of 
decorative  work. 

there  are  indications  that  the  marble  continues  beyond  it,  this  has  not  been  prove^l 
So  far  as  kuovvn,  the  marble  is  entirely  wanting  north  of  the  river.     South  of  the 

foi  200  to  300  feet,  when  they  are  again  cut  off  by  a  mass  of  granite. 

The  quarry,  to  which  I  was  guided  by  Professor  Crosby,  is  situated  in 
the  extreme  western  part  of  Westfield,  and  is  reached  by  leaving  the  electric 
cars  at  the  crossroads  east  of  the  old  Atwater  place  and  going  three-quarters 
ot  a  mile  south,  passing  two  houses  south  of  the  Little  Eiver  bridge  and 
gomg  west  by  a  field  road,  which  runs  northwest  about  a  half  mile 'to  a 
pomt  380  feet  above  the  sea  and  overlooking  the  valley  of  Little  River 

The  quarry  throws  much  light  on  the  problem  of  the  origin  of  the 
enstatite  beds.     It  contains  three  distinct  beds  of  first  importance- 

The  first,  the  "black  marble,"  like  that  of  the  old  Atwater  quarry,  is  a 
black  enstatite  rock  of  coarse  g.-ain  and  wholly  massive  structure  and 
shghtly  bronzy  luster  (the  enstatite  cleavage  showing  in  faces  one-half  inch 
m  width  by  2  to  4  inches  in  length),  now  in  various  stages  of  serpentinous 
change,  and  mottled  with  fohated  masses  of  bastite  (marmohte),  derived 
from  the  enstatite,  which  are  of  high  luster  and  rich  apple-green  color 

The  second  bed  is  a  black  spotted  marble-a  white  or  grayish,  rather 
coarsely  crystalline,  magnesian  limestone-containing  much  shining  tremo- 
lite,  effervescing  moderately  with  strong  hydi-ochloric  acid,  and  spotted  with 
elongate  crystals  of  the  same  black  altered  enstatite,  one-quarter  to  one-half 
mch  wide  and  2  to  6  inches  long.     These  make  a  very  regular  reticulate  or 
open  network  over  the  prevailing  white  surface  of  the  marble,  formino-  a 
remarkable  rock.     At  times  black  squares  of  the  mineral,  with  lighter  and 
less  changed  centers,  are  interspersed  with  the  narrower  rods,  and  the  latter 
radiate  from  the  centers  and  sides  of  these  squares  with  some  regularity 
and  connect  them  into  a  stellate  pattern  (see  fig.  8,  p.  152).      Again  the 
squares  may  wholly  replace  the  rods. 

These  two  beds  are  of  massive  structure  and  furnish  large  blocks 
which  take  a  fine  polish  and  promise  to  be  of  economic  importance. 

The  third  bed,  which  connects  the  other  two,  is  a  thin,  flat-foliated 
pale-green  to  white  marble,  with  films  and  flat  small  lenses  of  pale-green 


94  GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

to  rich  dark  oil-green  precious  serpentine.  The  surfaces  show  at  times 
narrow  bands  and  squares  of  serpentine  with  centers  of  straw-yellow  and 
borders  of  oil-green  color,  which  form  an  attractive  verd  antique,  plainly 
the  last  identifiable  stage  of  the  flattened-out  enstatites  that  the  rock 
formerly  contained.  It  is  further  clear  that  this  central  portion  never 
contained  so  much  enstatite  as  the  border  beds. 

The  country  rock  to  the  west  is  a  coarse  muscovite-biotite-schist,  with 
few  garnets  and  a  great  abundance  of  coarse-bladed  gray  cyanite,  which 
stands  out  in  reticulated  surfaces  on  the  weathered  slabs  and  will  furnish 
interesting  cabinet  specimens.  They  can  be  obtained  in  abundance  by 
following  the  path  along  the  serpentine  bed  south  to  the  first  wood  road 
and  then  going  up  west  along  the  wood  road  to  a  prominent  ledge  on  the 
south  of  the  road. 

Here  also  the  foliation  faces  of  the  coarse  schist  contain  rounded  and 
flattened  disks,  1  to  IJ  inches  long,  which  suggest  pebbles.  Earely  one 
can  be  seen  by  its  cleavage  to  be  in  part  feldspar,  but  most  are  a  quartz- 
biotite  mixture.  Also,  to  the  west  of  the  south  opening  made  by  the  com- 
pany, which  is  reached  by  going  up  a  wood  road  from  a  miner's  shanty,  the 
schist  shows  rounded  and  somewhat  oval,  white  surface  forms,  which  strongly 
suggest  the  trace  of  pebbles,  but  they  are  not  distinguishable  in  the  midst 
of  the  coarse  schist  when  it  is  freshly  broken.  The  rocks  stand  vertical, 
but  I  suppose  these  western  schists  to  be  older  than  the  serpentine.  The 
cyanite  follows  the  serpentine  and  amphibolite  for  many  miles  across 
G-ranville,  and  in  Barkhamsted,  Connecticut,  furnishes  the  finest  cabinet 
specimens. 

The  cyanite-schists  are  succeeded  from  west  to  east  by  the  following  beds: 

Section  at  the  main  mine. 

Feet. 

1.  Black  enstatite-serpentine 60 

2.  Green  laminated  crystalline  limestone 48 

3.  White  actinolitic  marble 3 

4.  Black  mottled  marble 30 

5.  Tremolitic  soapstone 8 

6.  Coarse  muscovite  granite 8 

The  eastern  country  rock  is  not  here  exposed,  as  the  high  terrace 
gravels  cover  the  area  to  the  east.  It  is  a  schist  like  that  on  the  west,  but 
without  cyanite.  A  band  of  rich-green  actinolite  three-fourths  of  an  inch 
wide  runs  across  both  of  the  principal  bands  of  the  quarry. 


THE  CHESTER  AMPHIBOLITE  AND  SERPENTINES.  95 

The  soapstone  has  been  worked  by  the  liidiam.  Ilalf-made  pots  are 
still  to  be  seen  on  the  surface,  and  an  Indian  arrow  was  found,  on  blastino- 
12  feet  down  in  a  narrow  crevice  in  the  limestone. 

To  the  north  of  the  quarry  the  bed  of  granite  cuts  off  the  serpentine 
band,  but  it  reappears  after  an  interruption  of  a  rod. 

Followed  a  few  rods  south,  the  western  contact  of  the  bed  is  exposed 
by  digging.  It  is  a  thick  bed  of  rich-green,  coarse-radiated  actinolite  mixed 
with  biotite,  and  the  wall  on  the  left  is  granite  with  some  plagioclastic  fringe 
rock  containing  biotite  and  tourmaline.  Nearly  the  whole  thickness  of  the 
bed  here  is  black  serpentine,  but  Professor  Crosby  pointed  out  to  me  a 
continuous  valley,  generally  quite  swampy,  which  may  be  occupied  by  the 
limestone  and  caused  by  its  solution. 

At  the  southern  outcrop  mentioned  above  (and  at  several  other  places) 
a  black,  flat  amphibolite  accompanies  the  serpentine  on  the  east,  but  does  not 
seem  to  be  in  great  force.  Here  the  radiated  tremolitic  character  of  the 
soapstone  is  specially  manifest.  It  forms  a  heavy  bed  on  the  east,  followed 
westerly  by  a  thin-foliated  verd  antique,  made  of  bands  of  blackish-green 
serpentine  and  white  marble,  with  about  20  feet  of  the  black  serpentine  to 
the  west  before  the  schist  is  reached. 

Farther  south  the  rock  crops  out  in  the  bed  of  Westfield  Little  River 
(bed  No.  19),  and  in  Westfield  (bed  No.  20)  north  of  the  Granville  road, 
near  the  west  border  of  the  New  Red  sandsone;^  south  of  this  road  it  crops 
out  in  the  hill  back  of  S.  Drake's  house  (bed  No.  21),  where  it  is  very  coarse- 
grained, exactly  like  the  East  Granville  locaUty,  and  from  the  weathering 
out  of  the  calcite,  which  fills  the  interstices,  it  is  very  rough-surfaced;  and, 
finally,  it  is  seen  in  the  bottom  (bed  No.  22)  of  Munn's  brook,  near  the  line 
between  Granville  and  Southwick.  It  is  in  place  where  the  brook  emerges 
from  its  gorge  in  the  hills.  The  prevailing  rock  is  a  black  enstatite-serpen- 
tine;  amphibolite  is  subordinate.  The  line  of  strike  then  carries  the  bed 
beneath  the  sands  of  the  Westfield  plain  and  it  is  not  seen  farther  south. 

FAtJLTS   AND   SERPENTINIZATION. 

The  great  Hoosac  fault  displaces  the  rocks  a  mile  on  either  side  of  the 
Deerfield  River,  below  its  bend  at  the  mouth  of  the  Hoosac  Tunnel.  It  seems 
possible  that  this  fault  plane  had  a  determining  influence  in  the  great  devel- 

» Hitchcock,  Geology  of  Mass.,  1841,  p.  159. 


96  GEOLOGY  OF  OLD  HAMPSHIKE  COUNTY,  MASS. 

opment  of  serpentine  from  tlie  hornblende-schist  bed,  since  this  extensive 
development  of  serpentine  extends  north  and  south  from  this  fissure,  and 
the  fault  perhaps  aided  the  work  by  bringing  to  the  bed  for  great  depths 
an  abundance  of  water,  and  may  have  further  intervened  by  localizing 
the  earthquake  forces,  which  may  have  shattered  the  rocks  for  a  distance  on 
either  side  of  the  fissure,  thus  aiding  the  chemical  activity  of  the  water. 
The  sharp  bend  of  the  stream  and  its  long  course  parallel  to  the  direction 
of  the  fault  show  that  the  fault  early  controlled  the  direction  of  the  river, 
and  it  probably  did  this  because  the  softened  rock  was  more  easily  eroded. 
The  next  large  area  of  serpentine — and  these  two  areas  are  vastly  larger 
than  the  others — is  in  Middlefield,  in  the  only  other  large  transverse  valley 
in  the  State.  Here,  also,  I  have  mapped  a  fault  in  the  valley  bottom,  and 
it  seems  probable  that  here  also  the  fault  may  have  had  something  to  do 
with  the  hydration  of  the  hornblende  to  serpentine,  as  well  as  with  the 
position  of  the  transverse  valley.  I  have  noted  also  a  sharp  bend,  which 
is  almost  a  fault,  at  the  Osborn  quarry.  The  other  serpentine  and  stea- 
tite deposits  are  comparatively  unimportant  in  size,  or  show  trace  of  olivine 
and  enstatite.  This  relation  did  not  attract  my  attention  until  the  field 
work  was  ended,  or  'other  similar  coincidences  might  have  been  detected. 

PETROGRAPHICAL    DESCRIPTION. 
THE   AMPHIBOLITES. 

1.  Epidotic  amphibolite. — Blandford;  North  Blandford  road  at  watering 
trough.  Typical  jet-black,  fissile  schist,  the  shining  hornblende  needles  just 
visible  to  the  eye.     Drusy  surfaces  of  epidote  and  adularia  upon  fissures. 

Under  the  microscope  the  abundant  hornblendes  appear  as  broad 
plates  with  strongest  extinction  and  pleochroism;  c>» !>:>■»,  c=blue-green, 
Ii=olive,  a=yellow.  Extinction,  22°  30'.  Interspersed  everywhere  among 
the  hornblende  needles  are  abundant  grains  of  pistachio-green  epidote. 
There  is  a  sparing  groundmass  of  rounded,  untwinned  albite  grains,  show- 
ing positive  bisectrix.  Magnetite  is  abundant,  but  no  leucoxene.  Rutile 
occurs  in  the  feldspar. 

3.  Feldspathic  amphibolite. — Blandford;  Osborn's  soapstone  quarry,  at 
west  junction  of  soapstone  bed  and  granite.  (See  p.  87.)  From  a  thin  bed 
of  black,  very  heavy  feldspathic  amphibolite,  20-30°""  wide,  with  fringe  of 
coarse,  black  transverse  biotite  lO"""  wide  adjoining  granite,  and  therefore 


THE  CHESTER  AMPHIBOLITE  AND  SEEPENTINES.  97 

carrying  orthoclase.  With  the  microscope  hornblende  in  broad  plates  with 
strongest  pleochroisin  and  absorption;  jc>lj>a,  jc=deep  blue,  tr=--deep 
olive,  a=straw  yellow.     Extinction  17°  30'. 

Orthoclase  is  abundant ;  plagioclase  occurs  with  extinction  24°.  Little 
magnetite  and  no  leucoxene.     Epidote  is  abundant. 

3.  AmpJiibolite.— Chester;  cutting  near  railroad  station  on  the  west. 
(See  PI.  VI,  fig.  4,  and  p.  160.)  A  finely  banded  rock;  interrupted  sheets 
of"  white  feldspar  grains  rather  distantly  placed  in  ground  of  jet-black 
hornblende  needles  of  high  luster,  all  parallel  to  the  common  direction  of 
the  stretching. 

Under  the  microscope,  stout,  long  blades  of  very  deep-green  horn- 
blende, with  distant  basal  partings  and  almost  no  prismatic  cleavage  visible, 
show  the  strongest  pleochroism  and  absorption  I  have  ever  seen,  the 
formula  for  which  is  the  same  as  in  the  last  case.  Between  the  bands  of 
these  stout  blades  a  coarse,  limpid  mosaic  of  plagioclase  gi-ains  occurs,  and 
very  little  magnetite  appears  in  the  slide.  The  plagioclase  is  an  oligoclase 
with  positive  bisectrix  and  extinction  at  +9°  to  the  trace  of  the  basal 
cleavage  on  M  [010]. 

THE    SERPENTINES    AND   ASSOCIATED    MAGNESIAN   ROCKS. 

In  the  long  hornblende-serpentine  band  which  stretches  across  the 
State  from  Rowe  to  Granville,  looping  back  in  the  last  town  so  as  to  be 
repeated  three  times  in  an  east-west  line,  the  serpentines  and  associated 
rocks  present  a  great  variety,  both  as  to  present  status  and  as  to  origin,  and 
one  can  distinguish  hornblende-serpentines,  pyroxene-serpentines,  enstatite- 
serpentines,  and  olivine-serpentines. 

There  are  associated  with  these  serpentines  beds  of  clinochlore,  tremo- 
lite,  actinolite,  corundum,  magnetite,  steatite,  talc,  and,  in  smaller  quantity, 
deweylite,  dolomite,  magnesite,  clii'omite,  chalcedony,  picrosmine,  diaclasite, 
bastite,  and  "phsestine." 

Of  these  the  first  five  represent  in  general  the  results  of  other  lines  of 
change  than  that  which  has  ended  in  serpentine,  or  at  times  a  stage  antece- 
dent to  the  change  into  the  latter  mineral. 

The  talc  and  steatite  can  be  traced  back  to  tremolite  or  actinolite  with 
or  without  the  intervention  of  a  serpentine  stage,  or,  the  purer  talc  especially, 
to  serpentine  of  any  origin;  the  secondary  dolomite,  magnesite,  magnetite, 
MON  xxix 7 


98  GEOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 

chromite,  and  chalcedony  are  surplus  products  of  the  serpentinous  change. 
Deweylite  and  picrosmine  are,  as  it  were,  special  varieties  of  the  main  pro- 
duct, while  diaclasite,  bastite,  and  "phaestine"  (or  marmolite)  are  derived 
directly  from  enstatite.  Of  course  remains  of  original  calcite,  dolomite, 
magnesite,  pyroxene,  epidote,  and  olivine  also  appear. 

BLADBD  serpentine;   ANTIGORITE-   (OR   BASTITE-)    SERPENTINE. 

1.  Serpentine  with  dolomite. — Rowe,  Massachusetts.  Large  bed  at  E. 
King's,  east  of  the  tunnel,  p.  79.  Compact,  even-grained,  splintery  fracture, 
dark-gray,  with  trace  of  green  on  fractured  or  sawed  surface,  deep  oil-green  to 
light  apple-green  on  polished  or  wetted  surface ;  very  translucent  in  splinters ; 
abundant  grains  of  pyrite  and  magnetite  scattered  through  the  mass.  Dr.  A.  J 
Hopkins  detected  chromium  in  small  amount;  for  analysis,  see  p.  116. 

Slides  show  with  pocket  lens  little  magnetite,  and  preserve  a  uniform 
pale-green  color,  even  when  ground  extremely  thin. 

Under  the  microscope  is  seen  a  network  of  interlaced  serpentine  blades 
of  unusual  range  in  size,  the  smaller  elongate,  irregularly  outlined  as  usual, 
rhombic,  and  polarizing  with  bluish- white  color;  the  larger  broad,  flat  plates, 
with  straight,  longitudinal  cleavage  lines,  polarizing  white  of  the  first  order 
at  border  and  deepening  to  yellow  at  center,  the  largest  filling  quarter  of 
the  field  (x  70)  and  deepening  in  color,  through  yellow  to  bright  magenta. 
These  serpentine  plates  are  sometimes  arranged  radially,  showing  a  black 
cross;  at  other  times  they  are  arranged  apparently  according  to  the  cleavage 
of  a  former  mineral,  and  are  accompanied  by  black  rod-like  microlites  in  the 
same  direction. 

Another  mineral,  talc,  appears  in  small  veins  and  broad  irregular 
patches,  as  well  as  i-eplacing  to  various  depths  certain  laminae  in  the  broad 
bastite  plates.  It  gives  an  aggregate  polarization  in  bright,  softly  blended 
colors,  with  wavy  and  sharp  zigzag  outlines.  Leucoxene  occurs,  surround- 
ing the  black  ore.  Dolomite  appears  at  times  in  regular  rhombohedi'a,  and 
is  generally  in  rounded  grains,  often  with  only  faint  traces  of  cleavage  and 
always  without  trace  of  twinning, 

2.  Serpentine. — Chester.  From  the  large  Middlefield- Chester  bed,  at 
brook-crossing  on  Chester  road  near  the  base  of  the  mass.  (See  p.  81.) 
Dull-black,  with  shade  of  brown;  same  color  when  wet;  conchoidal  fracture; 
massive. 


THE  CHESTER  AMPHIBOLITE  AND  SERPENTINES.  99 

With  a  lens  the  slide  shows  patches  of  separated  grains  of  a  yellowish, 
shining  mineral,  and  between  these  patches  run  broad  veins  of  the  amor- 
phous greenish  serpentine  and  many  magnetite  grains. 

Under  the  microscope  the  broad  veins  break  up  into  a  mass  of  very 
fine  bluish-white  blades,  and  the  same  lie  among  and  separate  the  brightly 
})olarizing  grains,  not  after  the  manner  of  the  olivine  network,  but  so  that 
the  grains  seem  to  be  scattered  and  woven  into  the  mass  of  needles  as  for- 
eign bodies,  a  single  needle  often  lying  lengthwise  in  a  crevice  between 
grains.  They  are  exactly  like  the  grains  of  epidote  in  the  epidotic  amphibo- 
lites.  Large  tracts  of  these  grains  polarize  together  and  show  a  single  axis 
Avitli  rings  of  color.  The  colors  are  also  not  so  bright  as  olivine  usually  is, 
and  it  is  probable  that  the  mineral  is  epidote. 

3.  Serpentine. — Chester.  From  the  tipper  portion  of  the  same  bed,  at 
its  south  end  on  Chester-Middlefield  road.  Eock  shows  original  bedding  in 
laminse  20-2.5°"°  thick,  and  fine  intricate  jointing,  the  latter  structure  brought 
out  by  weathering,  while  the  rock  still  cleaves  along  the  planes  of  the  first 
structure  and  shows  on  these  planes  a  brownish-gray,  shining  surface  and 
a  texture  that  is  suggestive  of  the  mica  membranes  of  the  sericite-schists 
above,  rather  than  of  the  hornblende-schists,  in  the  continuation  of  which 
it  lies.  The  rock  breaks  with  a  harsh,  fine- splintery  fracture,  is  of  rather 
light  greenish-gray  color,  translucent  and  mottled  with  black  when  wet. 

With  lens  the  section  shows,  beside  the  large  masses  of  magnetite,  wavy 
lines  of  fine  grains  of  magnetite  §°"°  apart,  which  run  out  and  are  replaced 
by  others.  These  are  seen,  in  sections  transverse  to  the  bedding,  to  be 
determined  by  the  cleavage  planes  mentioned  above,  and  represent  the 
original  fine  foliation  of  the  rock. 

The  mineral  shows  under  the  microscope  broad  bands  of  fiber  set 
transversely,  and  many  large  areas  of  disconnected  epidote  grains,  all 
polarizing  together. 

4.  Serpentine. — Chester.  From  the  same  bed  at  the  north  line  of  Ches- 
ter, 3J  feet  from  upper  surface  of  serpentine  bed  and  contact  of  sericite- 
schist.  Slaty  rock,  dark-gray,  dull  yellowish-green  and  translucent  when 
wet,  with  reddish-gray  sheen  on  cleavage  surface,  as  if  from  mica. 

The  slide  shows  no  large  grains  of  ore,  only  fine  magnetite  dust  arranged 
in  lines  running  in  various  directions,  and  no  unchanged  grains  of  any 
piimary  crystalline  mineral. 


100       GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

Under  the  microscope  very  fine  serpentine  needles  appear  arranged 
with  a  certain  paralleHsm  over  broad  surfaces,  a  structure  inherited  from  the 
fohation;  in  some  places  they  are  larger,  arranged  irregularly,  and,  being 
thicker,  show  bright  colors. 

Veins  of  chrysotile  occur,  with  a  certain  portion  of  the  transverse 
needles  replaced  by  magnetite.     For  analysis,  see  page  116. 

5.  Serpentine  nodule  in  talc. — Old  emery  mine,  Chester.  Light-gray  with 
shade  of  green;  pale-green,  translucent  when  wet;  very  fine-splintery  frac- 
ture, producing  a  whitish  surface,  as  if  dusted  with  fine  grains.  The  slide 
is  pale-green,  shows  large  grains  of  iron  ore,  and  bristles  with  magnetite  dust 
arranged  along  cleavage  laminae.    Many  spots  of  dolomite  are  visible  with  lens. 

Under  the  microscope  it  is  seen  to  be  made  up  wholly  of  a  network  of 
fine  serpentine  blades,  without  any  an-angement  significant  of  the  primary 
mineral  from  which  they  were  derived. 

6.  Serpentine. — Chester.  Another  interesting  serpentine  occurs  at  the 
emery  mine.  A  pale  apple-gi-een  to  oil-green  rock,  translucent,  with  shin- 
ing luster,  and  having  entirely  the  aspect  of  an  indurated  steatite;  H  =  2.5. 
It  breaks  into  thin,  shaly  fragments,  bounded  by  wavy,  slickensided  sur- 
faces, caused  by  pressure,  and  resembles  deweylite.  It  has,  however, 
specific  gravity  2.51,  and  under  the  microscope  has  the  structure  of  a 
platy  sei'pentine  and  polarizes  in  white  to  yellow  of  the  first  order,  and  it  is 
decomposed  by  hydi'ochloric  acid. 

The  serpentines  thus  far  described,  with  the  exception  of  those  from 
the  base  of  the  large  Middlefield  bed,  are  characterized  in  greater  or  less 
degree  by  the  following  peculiarities : 

(a)  A  harsh,  splintery  fracture. 

(h)  Secondary  magnetite  wanting  or  unimportant,  and  where  present 
arranged  often  in  long,  wavy  lines  of  the  original  lamination,  as  proved  by 
the  cutting  of  slides  at  right  angles  to  this  lamination  visible  on  weathered 
surfaces  of  the  rock. 

(c)  As  a  consequence  of  (V),  a  great  degree  of  translucency  in  the 
rock  when  wet  or  polished,  while  the  succeeding  enstatite-serpentines  are 
very  genei'ally  black  and  opaque  when  moistened. 

(d)  The  mass  of  the  rock  is  made  up  of  distinctly  polarizing  serpentine 
(antigorite)  in  bladed  crystals,  which  stand  in  relation  to  the  splintery 
fracture;  and  there  is  lack,  at  least  nearly  complete,  of  an  amorphous 
serpentine  substance  and  of  clirysotile. 


THE  CHESTEK  AMPHIBOLITE  AND  SERPENTINES.  101 

(e)  The  abundant  grains  of  a  brightly  pohirizing,  granular  minei'al 
seem  to  be  sometimes  ejiidote  inherited  from  the  amphibolite,  sometimes 
titanite  formed  around  grains  of  menaccanite  which  have  wholly  disap- 
peared, while  no  trace  of  olivine  can  be  detected. 

The  stratigraphical  indications  are  thus  reinforced  by  the  lithological 
study,  and  the  conclusion  is  rendered  probable  that  these  serpentines  are  in 
large  part  derived  from  the  amphibolites  with  which  they  are  associated. 
The  lack  of  any  direct  proof  of  the  presence  of  olivine  is,  however,  very 
far  from  proof  that  it  was  wholly  absent  from  these  beds.  Indeed,  this 
mineral  is  so  closely  connected  with  the  formation  of  serpentine  in  so  many 
cases  that  one  may  suspect  its  former  presence  here,  and  the  observations 
of  Kalkowsky  ^  on  the  presence  of  olivine  in  hornblende-scliists  led  me  to 
search  for  it  in  the  schists  adjacent  to  these  beds,  but  without  avail.  These 
rocks  plainly  also  resemble  Von  Drasche's^  serpentine-like  rocks  (now 
called  antigorite-serpentines),  and  can  be  easily  distinguished  from  the 
olivine-serpentines.  I  have  not,  however,  found  any  certain  trace  of 
diallage  in  them,  and  the  minerals  which  are  present  separate  them  quite 
distinctly  from  those  described  by  him. 

OLIVINE-  AND    lONSTATlTE-SBRPENTINE. 

7.  '^Serpentine,  Chester." — XIII,  No.  53,  Massachusetts  Survey  Col- 
lection. Rock  dull-black,  black  when  wet;  many  large  grains  of  magne- 
tite.    The  rock  weathers  superficially  to  carbonate. 

With  lens  the  slide  is  pale-green,  and  shows  the  secondary  magnetite 
occupying  planes  of  lamination  and  a  fine  system  of  joint  planes  nearly  at 
right  angles  to  these  and  very  regular. 

Under  the  microscope  an  olivine  network,  inclosing  in  one  slide  frag- 
ments of  unchanged  olivine,  in  another  lacking  these  altogether,  runs 
through  the  slide  without  being  influenced  at  all  by  the  lamination  and 
joint  planes  mentioned  above. 

This  network  runs  through  a  base  of  nonpolarizing  serpentine.  I  am 
not  able  to  locate  this  specimen,  but  suspect  that  it  comes  from  the  base  of 
the  large  Middlefield-Chester  bed,  or  from  the  smaller  bed  upon  the  top  of 
North  Mountain. 

Serpentine. — "The  Crater,"  North  Blandford.  The  rock  of  the  crater 
is  easily  distinguished  both  macroscopically  and  microscopically  from  that 

'Die  GneisBformation  des  Eulengebirges.  p  37;  Tsohermaks  mineral.  Mittheil.,  1871,  p.  1. 
^Ueber  Serpentin  und  Serpentinahnliche  Geeteine:  Tsohermaks  mineral.  Mitthi-ll.,  1871,  p.  1. 


102  GEOLOGY  OE  OLD  HAMPSHIKE  COUNTY,  MASS. 

of  any  otlier  locality  in  tlie  range.  It  is  dark-gray,  scarcely  shaded  with 
green,  spotted  full  of  primary  magnetite  in  large  grains,  and  weathering 
uniformly  through  light  green  to  fawn  color.  It  is  very  compact  and  tough 
and  much  jointed.  A  quaHtative  analysis  detects  about  1  per  cent  of  chro- 
mium in  the  specimen  from  which  slides  were  cut  (Dr.  A.  J.  Hopkins). 

With  the  lens  the  slide  shows  no  trace  of  magnetite  dust,  but  is  frosted 
all  over  with  shining  grains  of  a  yellowish-white  crystalline  mineral. 

Under  the  microscope  the  ground  is  a  confused  tangle  of  bluish-white, 
rhombic  needles  of  extreme  fineness,  and  the  shining  grains,  polarizing 
brightly,  are  scattered  in  it  so  much  like  foreign  grains  that  I  suspected  the 
slide  to  have  been  badly  cleaned  of  the  corundum  used  in  polishing,  and  cut 
new  ones  carefully,  but  with  the  same  result.  The  mineral  polarizes  with 
about  the  brightness  of  pyroxene;  the  angular  grains  are  fresh  to  the  edge 
and  show  no  cleavage;  some  of  the  larger  show  a  single  axis  with  rings  of 
color.     It  does  not  gelatinize  with  hydrochloric  acid.     For  analysis,  see 

page  116. 

8.  Olivine-serpentine. — Osborn's  soapstone  quarry,  Blandford.  Eastern 
bed.     (See  fig.  5  and  page  87.) 

Except  one  specimen  from  Chester,  whose  exact  location  is  not  known 
to  me  (Massachusetts  Survey  Collection,  XIII,  No.  63,  described  on  p.  101), 
this  is  the  only  bed  in  the  long  series  of  outcrops  west  of  the  river  which 
contains  olivine  in  abundance.  In  all  the  beds  hitherto  mentioned  its  occur- 
rence could  at  best  be  rendered  only  probable,  though  I  have  little  doubt 
that  it  was  formerly  present  in  many  cases.  In  all  the  beds  discussed  below 
the  absence  or  rarity  of  olivine  is  equally  certain,  and  the  derivation  of  the 
serpentine  from  pyroxenite  or  coarse  enstatite  rock  is  quite  clear.  Indeed, 
much  of  the  rock  is  so  Httle  changed  that  it  could  be  as  properly  called 
enstatite  rock  as  serpentine. 

The  great  mass  of  the  rock  where  freshest  is  dull-black,  opaque  when 
wet,  with  the  marked  shining,  greasy  luster  characteristic  of  those  serpentines 
which  still  contain  olivine  in  abundance.  It  gelatinizes  abundantly  with 
acid,  and  the  solution  contains  magnesium  and  iron,  with  trace  of  calcium. 

A  layer  of  surface  decomposition  of  a  drab  or  grayish  olive-green  color 
and  10-20""  thick  covers  the  surface,  and  is  sharply  demarcated  from  the 
black  interior.  It  is  caused  largely  by  the  removal  of  the  black  ore,  and  the 
rock  within  its  Umits  has  much  more  the  look  of  ordinary  olivine  than  in  the 


THK  CllESTEU  AMPHIBOLITE  AND  SERPENTINES.  103 

black  center.  The  weathered  layer  is  distinctly  softer,  and  although  the 
change  to  serpentine  is  not  more  advanced  than  in  the  interior,  the  olivine 
fragments  polarize  much  less  brilliantly  than  in  the  black  portion.  They 
may  be  referred  to  villarsite. 

In  both  the  interior  and  the  weathered  crust  occur  distantly  scattered 
spherules,  about  10°""  across,  of  a  finely  radiated  tremolite-asbestos.  They 
are  not  bounded  by  a  true  spherical  surface  outwardly,  but  long,  delicate 
needles,  just  visible  with  a  strong  lens,  project  far  beyond  the  average  sur- 
face. The  impression  is  very  strong  that  these  latter  are,  as  it  were,  feelers 
thrust  forward  into  the  mass  from  a  center  of  alteration. 

Many  of  the  spheres  are  changed  wholly  or  partly  into  talc,  the  change 
starting  at  the  center  and  following  up  the  other  to  the  periphery,  and, 
especially  in  the  outer  layer,  resulting  in  the  entire  change  of  the  sphei-ule 
into  talc;  and  as  the  steatite  bed  into  which  the  serpentine  grades  has  the 
same  radiated  fibrous  texture,  it  has  apparently  been  derived  from  the 
latter  after  the  same  manner. 

These  radiated  tufts  bear  also  some  resemblance  to  the  radiated  asbestos 
zone  surrounding  the  garnets  of  the  Saxon  "garnet-serpentines,"  described 
by  Dathe,^  though  here  no  garnet  center  can  be  observed,  and  the  radiating 
mineral  is  much  coarser  than  would  accord  with  the  description  of  the 
Saxon  occurrence.  Indeed,  garnet,  so  abundant  in  the  next  higher  forma- 
tion, is  here  curiously  absent  from  the  amphibolites  and  associated  rocks 
clear  across  the  State. 

Slides  of  the  freshest  black  portion  of  the  rock  appear  under  the  lens 
to  be  made  up  of  angular  grains  of  olivine,  often  quite  complete  crystals, 
without  admixture  of  anything  else  except  a  black  ore  arranged  in  rudely 
parallel,  interrupted  lines.  The  bleached  outer  layer  shows  nothing  differ- 
ent, except  that  the  black  ore  is  removed  and  the  whole  soaked  full  of 
iron  rust. 

Under  the  microscope  the  slides  show  the  finest  olivine  network;  the 
broad  meshes  of  chrysotile  are  beautifullj^  developed  and  occixpy  about  a 
third  of  the  area.  The  olivine  is  without  inclusions,  except  small  chromite 
octahedra,  and  rarely  long  series  of  straight,  black  needles,  which  are 
arranged  parallel  to  the  vertical  axis  and  at  right  angles  to  the  length  of 
the  series  with  the  regularity  of  a  micrometer,  except  that  some  lines  are 

1  Oliviiifels,  Serpentm,  and  Eklogit  des  sachischen  Granulitgebietes :  Neues  Jahrbuch,  1876,  p.  225. 


104       GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

prolonged  far  beyond  the  others.  Highly  magnified,  they  are  reddish  and 
translucent.  In  other  portions  of  the  slide  the  characteristic  enstatite- 
serpentine  occurs,  with  exactly  the  structure  of  fig.  3,  PI.  II. 

In  the  outer,  bleached  layer  the  lines  of  magnetite  dust  in  the  suture  of 
the  chrysotile  bands  have  disappeared  and  in  the  form  of  limonite  have 
soaked  through  the  fibrous  chrysotile.  With  further  process  of  change  the 
latter  loses  its  fibrous  character,  and  every  trace  of  the  origin  from  olivine 
disappears.  At  times  also  the  olivine  grains  here  retain  their  position  in 
the  clu-ysotile  network  and  their  appearance,  but  have  lost  their  bright 
colors  of  polarization.  The  change  of  the  olivine  to  tremolite  seems  to  be 
of  earlier  date,  and  has  often  advanced  to  the  replacement  of  nearly  all  the 
olivine.  It  appears  to  have  occurred  earlier  than  and  independently  of  the 
superficial  weathering,  because  the  tremolite  is  found  in  equal  abundance  in 
the  fresh  interior  and  in  the  weathered  surface. 

Where  the  olivine  is  weathered,  as  in  specimens  taken  from  large 
bowlders  on  the  West  Granville  road,  just  where  the  glacial  currents  would 
cany  material  from  this  bed,  the  specimens  are  not  distinguishable  from 
corresponding  specimens  from  the  Pelham  and  Shutesbury  beds  (see  p.  47), 
and  I  had  expected  confidently  to  find  the  fibrous  mineral  to  be  antho- 
phyllite,  and  indeed  its  powder  gives  fragments  which  foi-  the  most  part 
extinguish  longitudinally,  but  at  times  other  fragments  extinguish  with 
an  angle  of  11°  to  15°  to  the  length,  and  show  a  single  optical  axis  placed 
laterally,  exactly  as  in  hornblende. 

A  cleavage  parallel  to  go  P  oo  (100)  seems  to  be  unusually  well  devel- 
oped, and  most  fragments  rest  upon  it  and  so  extinguish  longitudinally,  but 
show  only  one  axis,  as  in  hornblende.  It  is  to  be  noted  that  this  is  from  a 
unique  bed  lying  east  of  the  main  hornblendic  band.     (See  p.  89.) 

9.  Pyroxene-serpentine. — Lowest  bed,  near  Osborn's  quarry.  (Fig.  5, 
p.  87.)  The  lowest  bed  at  the  margin  of  the  north-south  brook  in  the 
woods  below  Osborn's  quany  attracted  my  attention  immediately  as  some- 
thing quite  unlike  any  other  rock  connected  with  the  serpentine  series,  to 
which  it  manifestly  belonged;  indeed,  unlike  any  rock  with  which  I  was 
acquainted. 

The  weathered  surface  is  for  the  most  part  rough  and  warty,  dirty 
white,  and  covered  with  shining  scales  of  talc.  In  some  places  this 
layer,  5-10"""  thick,  is  covered  by  a  white,  powdery  layer  of  magnesite. 


PLATE   II. 


105 


PLATE    II. 

THIN  SECTIONS. 

Fig.  1.— Sahlite  changing  into  tremolite;  the  hitter  heginning  to  change  into  serpentine.  From  the 
lower  hed  at  Oshoru's  soapstone  quarry,  Blaudford.     X47.     See  pp.  87,  104. 

Fig.  2. — Dolomite  changing  to  serpentine.     Granville.     X28.     See  p.  110. 

Fig.  3.— Enstatlte  crystal  altered  to  serpentine,  cut  parallel  to  (001).  Drawn  with  polarized  light 
and  with  the  light  bands  placed  at  45°  to  the  plane  of  polarization.     x60.     See  p.  110. 

Pig.  4. —Garnet,  with  complex  border;  from  pegmatite.     Northfield.     Xl4.     See  p.  328. 

106 


MONOORAM  A . 


ATI 

8  THIN  SKCTIONS 

-Bablite  c-bani^injr  into  tremol 


■il,  lo-i. 


i;toue  nuuiry,  IWai.'. 

tine.     Granville.     .. 
itcrcil  to  serpentine,  out  parallel  to  (001).    Drawn  witli  polarized  light 
ht  bands  placed  at  45°  to  the  plane  of  polanVnti""      -fill     j^i  ii  p    no 
lex  border;  from  pegmatite.    Northfield.     X 


U.   S.   GEOLOGICAL  SURVEY 


MONOGRAPH  XX(X      PU    11 


THIN   SECTIONS. 


THE  CHESTER  AMPHIBOLITE  AND  SERPENTINES.  107 


fP 


riic  interior  is  ;i  dark  oil-greeu,  flecked  with  white  or  yellow;  opaque 
black  when  wet,  and  witli  pecuHar  greasy  luster  i-eflected  from  large 
cleavage  surfaces,  which  run  through  the  whole  mass.  These  surfaces  reach 
a  size  of"  20  x  40""",  have  a  pearly  luster,  and  are,  in  many  cases  where  the 
rock  is  deei)lv  weathered,  bleached  to  an  isabella-yellow  or  changed  to 
a  white  mass  like  kaolin.  They  are  covered  with  an  acute-angled  network 
from  a  second  cleavage,  like  that  of  hornblende,  but  more  acute,  and  a 
satiny  sheen  runs  over  the  face  from  the  presence  of  fine  tremolite  needles, 
arranged  parallel  to  this  cleavage  and  gradually  encroaching  upon  the 
original  mineral,  which  proves  upon  microscopical  study  to  be  sahlite. 
Slices  cut  parallel  to  the  perfect  parting  (see  fig.  1,  PI.  II),  which  proves 
to  be  0  P  (001),  show  a  fine,  regular  network  of  tremolite  needles,  which 
polarize  with  an  obliquity  of  about  15°  and  coincide  in  position  with  the 
acute  cleavag-e  of  the  orig-inal  mineral  mentioned  above.  Where  this 
secondary  tremolite  has  not  come  to  occupy  the  whole  space  the  meshes 
are  occupied  by  a  colorless  sahlite,  showing  in  traces  an  interrupted  pris- 
matic cleavage  and  a  delicate  lineation  parallel  to  go  P  oo  (100),  with  traces 
of  a  second  at  right  angles  to  this.  In  the  figure  this  fine  lineation  is  of 
necessity  too  coarsely  represented,  it  being  visible  only  with  high  power, 
and  it  is  given  specially  to  show  the  extent  of  the  unchanged  sahlite.  The 
latter  polarizes  with  .extreme  brilliancy,  and  characteristic  sudden  changes  of 
tint  appear  over  its  sm'face,  arising  from  the  brittleness  of  the  thin  laininse 
due  to  the  very  easy  parting  on  0  P  (001),  which  renders  it  difficult  to  polish 
it  to  a  true  surface. 

The  mineral  is  positive,  and  the  optical  axial  plane  is  at  right  angles 
to  the  fine  lineation — i.  e.,  is  in  oo  P  co  (010) — and  a  single  axis  appears, 
and  this  plane  bisects  the  acute  angle  of  the  tremolite  network,  which  meas- 
ures about  54°.  This  would  make  the  cleavage,  which  has  determined  the 
position  of  the  tremolite  fibers,  approximate  to  co  P  2  (120),  the  counterpart 
of  oo  P  2  (210) — the  prism  of  hornblende  when  reckoned  upon  the  pyroxene 
axes.  An  examination  of  tlie  Bolton  (Massachusetts)  sahlite  shows  that  dis- 
tinct traces  of  the  same  cleavage  existed  in  fresh  specimens.  Here,  as  is  not 
unusual,  it  is  rendered  much  more  distinct  in  the  process  of  decomposition. 

In  slices  cut  at  right  angles  to  the  perfect  basal  cleavage  or  parting 
the  strong  equidistant  lines  of  separation  are  the  marked  feature,  and  these 
lines  quite  far  apart  are  the  seat  of  most  advanced  change. 


108  GEOLOGY  OP  OLD  HAMPSHIRE  COUNTY,  MASS. 

The  perfect  sahlite  cleavage  is  also  retained  after  tlie  change  to  serpen- 
tine is  far  advanced,  and  shines  out  when  the  piece  is  held  in  a  particular 
position  as  single  faces  luster-mottled  with  small  opaque  spots  of  serpentine. 
In  the  process  of  change,  black  iron  ores  in  rods  and  lines  of  dots  appear 
in  the  interstices  of  the  tremolite  needles,  as  Avell  as  in  the  prismatic  and 
pinacoidal  cleavage  of  the  sahlite;  and  after  the  serpentinous  change  (which 
commences  in  the  transverse  cleavages  of  the  tremolite  and  advances  in  a 
network  somewhat  like  that  in  olivine)  has  completely  transformed  the 
whole  into  a  confusedly  polarizing  mass,  the  acute-angled  network  is  as 
clearly  marked  in  ordinary  light  as  before  by  the  black  lines,  and  in  places 
traces  of  the  rectangular  pyroxenic  cleavages  can  also  be  seen. 

In  the  most  completely  changed  portions  blades  of  actinolite,  either 
later  formed  than  the  tremolite  or  more  resistant  than  it,  show  marked  ple- 
oclu-oism  for  so  nearly  colorless  a  mineral — pale  blue-green  to  ochei'-yelloAv. 

10.  Enstatite-serpentine  and  steatite. — Hartland,  Connecticut,  just  south 
of  the  town  line,  where  the  road  from  West  Granville  to  Hai'tland  crosses 
Hubbard  Brook.  On  passing  100  feet  up  the  slope  southwest  of  the  bridge 
the  black  enstatite-serpentine  occurs  in  force.  It  is  of  finer  grain  than  the 
other  beds  to  the  north,  with  which  it  otherwise  agrees  exactly,  and  it  is 
largely  changed  to  steatite. 

11.  Tremolite  rock  and  enstatite-serpentine. — J.  Downey,  Granville.  Fol- 
lowing a  wood  road  east  into  the  densely  wooded  swamp  from  a  point  just 
north  of  the  house  of  Mr.  J.  Downey,  I  came  upon  a  very  interesting  out- 
crop, which  represents  the  first  occurrence  of  serpentine  upon  the  amphibolite 
band,  where,  after  turning  north,  it  swings  around  the  gneiss  of  Granville. 

Along  east  of  a  band  of  the  common  amphibolite  there  crops  out  a 
low  ridge  of  limestone,  at  times  quite  pure,  light-gray,  and  thin-fissile, 
but  taking  more  and  more  very  fine  tremolite  into  its  composition,  until 
it  comes  to  be  a  flat-fissile,  pale-green  tremolite-schist,  almost  as  fine- 
grained as  nephrite,  which  it  somewhat  resembles.  It  polarizes  brilliantly, 
has  extinction  in  maximum  27°,  and  shows  a  few  straight,  black  microlites 
and  a  few  large  grains,  also  visible  to  the  eye,  of  a  black  magnetic  ore.  It 
gives  on  analysis  only  traces  of  AlgOg,  FeO,  and  CaO,  and  is  an  almost  pure 
silicate  of  magnesia. 

South  of  this  there  are  no  exposures  for  a  short  distance,  and  in  the 
strike  of  the  tremolite  rock  rises  a  great  knob  of  enstatite  rock.     It  is  a 


THE  OnESTER  AMPHIBOLITE  AND  SERPENTINES.  109 

coarso,  ragged  rock,  made  up  of  cr3^stals  of  enstatite,  often  10  x  (!  x  4™  in 
size;  and  no  other  original  constituent  can  be  detected  except  dolomite, 
which  is  inclosed  in  large,  rounded  grains  in  the  freshest  enstatite.  Indeed, 
in  much  of  the  mass  the  whole  is  made  up  of  the  large,  imperfect,  interlaced 
prisms.  These  are  thickly  coated  by  a  greenish-gray  talc-like  product  of 
decomposition,  which  also  penetrates  in  thick  layers  along  the  perfect  cleav- 
age until  tlie  whole  is  changed  into  bastite  and  ultimately  into  talc.  Where 
the  change  is  more  advanced,  great  sheets  and  remnants  of  the  bastite, 
gray-green  in  color,  lie  in  a  mass  of  black  serpentine,  or  in  a  mixture  of 
this  and  a  yellow  dolomite.  Often,  however,  the  enstatite  rock  seems  to 
degenei'ate  into  a  talc-like  mass  without  an}?^  trace  of  serpentine,  and  the 
masses  of  black  serpentine  and  dolomite  may  have  originally  contained 
some  other  mineral  besides  the  enstatite,  though  I  could  obtain  no  proof 
of  this. 

Under  the  microscope  the  enstatite,  cut  parallel  to  the  perfect  cleavage, 
shows  in  the  freshest  portions  only  a  few  black  mici'olites,  but  it  is  much  cut 
up  by  a  network  of  yellow  serpentine ;  and  here  large  octahedra  of  magne- 
tite appear.  With  convergent  light  it  polarizes  in  bright  colors,  and,  of 
course,  shows  no  axes,  and  on  moving  the  slide  spaces  are  found  which 
show  the  axes  as  in  diaclasite,  accompanied  with  bright  colors,  and  these 
parts  are  not  distinguishable  in  ordinary  light  from  the  unchanged  ensta- 
tite. Moving  the  slide  a  little  farther,  one  sees  the  axes  as  in  bastite  and  in 
paler  colors,  and  in  common  light  these  parts  have  the  appearance  of  ser- 
pentine. The  divergence  of  the  optical  axes  is  very  small  for  the  bastite, 
certainly  less  than  30°.  Embedded  also  in  the  black  serpentine  are,  rarely, 
large  scales  of  a  deep-green  clinochlore,  with  divergence  of  the  optical 
angles  of  about  10°. 

By  the  roadside  near  the  cemetery,  southwest  of  the  last  locality,  are 
found  bowlders  of  all  the  varieties  of  rock  mentioned  from  this  outcrop,  and 
several  others  of  interest  which  seem  also  to  come  from  this  place,  although 
this  can  not  be  made  certain.  One  great  mass  of  limestone  is  in  places 
banded  in  dull  black,  from  the  large  amount  of  magnetite  in  the  limestone. 
It  shows  also,  under  the  microscope,  a  large  number  of  fine  actinolite  needles 
and  rarely  a  grain  of  coccolite,  and  this  piece  is  so  exactly,  in  other  parts, 
like  the  tremolitic  limestone  found  in  place  north  of  the  serpentine  knob 
that  it  is  scarcely  possible  that  one  can  err  in  assigning  to  them  the  same 


110  GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

origin.     It  contains,  however,   bands    several  centimeters   broad  of  dark- 
green,  matted,  fibrous  actinolite. 

Associated  with  this  in  another  large  bowlder  is  an  entirely  distinct 
limestone,  a  white,  coarse,  granular  calcite,  all  the  grains  showing  with  the 
lens  abundant  twin  striation,  while  the  limestone  mentioned  above  is 
too  fine-grained  to  allow  its  structure  in  this  respect  to  be  seen,  and  under 
the  microscope  it  is  not  twinned  at  all.  It  must  be  calcite,  however,  as  it 
effervesces  freely  with  cold  acid.  In  the  limestone  now  described  a  distinct 
stratification  is  effected  by  the  interposition  of  fibrous  masses  of  emerald- 
green  actinolite  upon  the  foliation  planes,  and  in  the  midst  of  the  granular 
calcite  fine  grains  of  coccolite  and  magnetite  occur. 

12.  ^^Dolomite-serpentine,  Granville^ — XIII,  No.  26,  Massachusetts  Sur- 
vey Collection ;  PI.  II,  fig.  2.  This  is  a  black  serpentine,  containing  much 
white  to  greenish,  granular  dolomite,  and  is  identical  with  the  bowlders 
described  above  from  near  the  cem.etery  in  Grranville.  Remnants  of  the 
gi-ay-green  enstatite  in  every  stage  of  change  to  phgestine  appear,  and  prove, 
under  the  microscope,  identical  with  those  described  above,  and  the  traces 
of  enstatite  structure  can  also  be  distinctly  seen  in  the  completed  serpentine. 

The  most  interesting  change  here  is  that  of  the  dolomite  into  chrysotile, 
many  stages  of  the  Eozoon  structure  being  beautifully  represented. 

The  slide  (PL  II,  fig.  2.)  shows  a  network  of  yellow  serpentine, 
amorphous  in  common  light,  running  through  the  dolomite  and  generally 
following  the  cleavage.  The  dolomite  network  appears  where  the  car- 
bonate has  wholly  disappeared.  The  dolomite  fragments  are  surrounded  by 
a  quite  broad,  dark  band,  consisting  of  short,  stout  rods  of  the  unchanged 
dolomite  which  project  into  the  serpentine. 

The  dolomite  shows  exceptional  absorption,  and  this  dark  band  absorbs 
and  extinguishes  with  it.  Outside  this  band  the  serpentine  veins  polarize 
with  wavy  extinction  and  low  colors,  and  show  the  moat  delicate  fibrous 
structure,  with  central  suture. 

13.  Enstatite-serpentine. — H.  Cooley,  Granville  (PI.  II,  fig.  3).  The 
section  cut  parallel  to  the  base  of  the  large  crystals  of  enstatite  changed  into 
serpentine  shows  a  series  of  bands  which  appear  in  pairs  separated  by  a 
narrow  line  of  magnetite.  These  are  the  light  bands  seen  in  the  figure,  and 
broad  surfaces  could  have  been  selected  where  these  bands  were  more  closely 
parallel  than  in  the  one  drawn.     The  drawing  was  made  with  crossed  nicols. 


.1 


0&S^ 


THE  CHESTER  AMPHIBOLITE  AND  SERPENTINES.  1 1 1 

and  the  light  bands  are  placed  at  45°  to  the  plane  of  the  instrument.  Parallel 
with  this  plane  they  are  black.  They  show  an  extremely  fine,  transverse, 
fibrous  structuj-e.  The  intervening  lens-shaped  fields,  dark  in  the  drawing, 
are  black  in  this  position  at  45°  when  the  bands  are  white;  when  rotated  to 
0°  they  sliow  white,  radiate-fibrous  tufts  on  a  black  ground  of  nonpolarizing 
serpentine. 

The  deposition  of  magnetite  in  certain  of  the  places  of  perfect  cleavage 
was  accompanied  by  the  very  regular  change  to  fibrous  serpentine  growing 
out  from  the  planes  and  forming  the  white  bands.  Then  the  gi-owth  of 
secondary  serpentine  between  some  of  these  bands  has  seemingly  wedged 
them  apart,  and  given  them  their  curved  forms  and  produced  the  lenticular 
fields  of  serpentine. 

14.  "Serpentine  (bowlder).  Blandford."  XIII,  No.  11,  Massachusetts 
Survey  Collection,  1841  ;  No.  880,  1835. — Compact,  fresh  surface,  bluish- 
black,  mottled  with  dull  brownish-black;  contains  much  magnetite;  is  unlike 
any  other  serpentine  known  by  me  from  this  region,  and  comes,  doubtless, 
from  the  bowlders  noted  by  Dr.  Hitchcock  on  the  east  line  of  the  town.-' 

With  the  lens  the  slide  is  seen  to  be  mottled  with  large  green  spots,  which 
were  doubtless  formerly  enstatite  and  which  retain  its  structure,  though  com- 
pletely changed;  and  in  other  spots  traces  of  an  olivine  network  can  be  made 
out  with  much  probability.  The  rock  is,  however,  for  the  most  part  com- 
pletely changed,  and  shows  everywhere  the  softly  colored  polarization  of  talc. 

15.  Enstatite-serpentine. — Atwaters,  Russell.  Following  the  hornblende 
band  northward  to  the  point  where  it  bends  round  through  the  southeastern 
corner  of  Blandford,  where  I  suppose  the  above  specimen  No.  11  of  the 
Massachusetts  Survey  Collection  was  obtained,  we  come  upon  the  great  out- 
crop in  the  high  hill  in  Russell  overlooking  the  Westfield  plain,  where  many 
years  ago  the  rock  was  quarried  extensively  as  black  marble  by  Mr.  Atwater, 
the  father  of  the  present  proprietor. 

The  black  serpentine  presents  no  peculiarities  by  which  it  can  be  dis- 
tinguished microscopically  from  the  other  localities  in  Granville  and  Russell. 
Because  of  the  deep  quarrying  the  finest  specimens  can  be  obtained  from 
this  place,  and  the  bastite  is  of  a  beautiful  apple-green  color,  instead  of  the 
pale  gray  seen  elsewhere,  and  was  found  by  Tschermak  to  have  the  low 
angle  of  30°  for  the  optical  axes. 

'  E.  Hitchcock,  Geol.  Mass.,  1841,  p.  617. 


112  GEOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 

In  a  considerable  number  of  thin  sections  the  enstatite  structure  was 
found  everywhere  strongly  marked  by  broad,  distant,  granular  bands  of 
black  ore,  with  very  numerous  straight,  narrow  lines  made  up  of  rods  and 
grains  of  the  same  black  ore  and  running  at  right  angles  to  the  broad  bands. 
No  trace  of  enstatite  could  be  found  unchanged,  and  the  broad  apple-green 
plates,  which  are  often  quoted  as  marmolite,  from  these  localities  had  passed 
for  the  most  part  beyond  the  bastite  stage  into  a  network  of  serpentine 
needles,  in  which  isolated  bastite  plates  still  remain. 

Irregular  grains  and  large  patches  of  carbonate,  much  corroded  and 
polarizing  with  a  soft  amber  color,  with  faint  irised  border,  occur  every- 
where; also  miscroscopic  veins  of  satin  spar,  sometimes  insinuated  in  large 
number  between  successive  plates  of  the  bastite. 

No  trace  of  olivine  structure  could  be  discovered  in  any  of  the 
slides  from  this  locality;  and  in  the  localities  described  later,  where  the  rock 
is  less  changed,  it  could  be  seen  that  all  of  the  rock  exposed  was  made  up 
of  large  enstatite  crystals  so  closely  apposed  that  there  could  have  been  at 
best  only  a  trace  of  olivine  present;  and  on  the  broad  cleavage  surfaces  of 
the  enstatite  no  trace  of  included  olivine  grains  could  be  seen.  The  structure 
in  the  completed  serpentine  was  everywhere  the  rectangular  network,  as 
characteristic  of  the  enstatite-serpeutine  as  the  olivine  network  is  of  the 
latter  mineral.  It  is  beautifully  illustrated  by  Dr.  Wadsworth  in  pi.  7,  fig. 
2,  of  his  Lithological  Studies,^  from  a  specimen  obtained  "four  miles 
from  Westfield  Center,  Westfield,  Massachusetts."  This  must  have  come 
from  the  Atwater  ledge,  which  is  just  4  miles  west  of  Westfield  callage, 
but  lies  across  the  line  in  Russell.  As  the  rock  from  which  the  serpentine 
was  derived  was  a  nearly  or  quite  pure  enstatite  rock.  Dr.  Wadsworth's 
assignment  of  it  to  the  peridotites  can  not  be  accepted. 

16.  " LigJd-green,  compact  serpentine. — Russell."  XIII,  No.  25,  Massa- 
chusetts Survey  Collection.  This  is  a  superficial  layer  a  few  millimeters 
in  thickness,  which  also  runs  in  veins  into  the  black  serpentine,  and  is  super- 
ficially covered  by  a  rusty  white  layer.  It  is  probably  from  the  surface  of 
the  above  bed.  It  presents  under  the  microscope  a  tremolitic  structure 
throughout — radiated,  fibrous,  a  late  stage  of  the  change  into  serpentine. 

17.  '■^Serpentine  (bowlder). — Russell."  XIII,  No.  50,  Massachusetts 
Survey  Collection.     This  is  certainly  an  erratic  derived  from  the  great  bed 

1  Mem.  Una.  Comp.  Zool.  Harvard  Coll.,  Vol.  XI,  pt.  1,  1884. 


THE  CnESTEE  AMPHIBOLITE  AND  SEEPENTINES.  113 

in  Middlefield,  and  probably  found  in  the  valley  of  the  Westfield  in  the 
north  part  of  Russell. 

18.  "Black  serpentine,  talc,  actinolite. — Westfield."  XIII,  No.  24, 
Massachusetts  Survey  Collection.  Subgranular,  dull  black,  very  little  talc, 
derived  from  enstatite. 

The  actinolite  mentioned  above  is  in  part  enstatite  partially  changed 
to  bastite,  in  part  fine  radiating  tufts  of  tremolite,  green  from  the  back- 
ground of  serpentine.  The  rock  is  traversed  by  veins  of  snow-white, 
fibrous  calcite  20-30°"°  long  and  2™"  wide,  with  satiny  transverse  fibers 
and  central  suture. 

It  shows  under  the  microscope  large  masses  of  unchanged  pjrroxene 
with  coarse  co  P  cleavage,  and  long,  black  microlites,  often  crossing  each 
other  rectangularly  in  three  directions.  It  changes  outwardly  into  coarse, 
radiated,  fibrous  tremolite  (cleavage  124°),  which  is  altered  along  prismatic 
and  transverse  cleavage  into  serpentine. 

19.  ''Serpentine  and  calcite. — Westfield."  XIII,  Nos.  27,  28,  29,  30, 
Massachusetts  Survey  Collection.  The  first  two  are  wanting  in  the  collec- 
tion. No.  29  is  a  contact  piece  of  dolomite,  with  light-green  and  straw- 
colored  serpentine  running  out  into  it  from  a  mass  of  oil-green  serpentine 
with  fine,  broad  veins  of  chrysotile  and  many  characteristic  eozoonal  struc- 
tures. It  shows  beautifully  every  stage  of  the  change  of  dolomite  into  a 
colorless,  almost  perfectly  amorphous  serpentine,  showing  no  needles  and 
only  faint  patches  of  color  with  crossed  nicols,  and  in  many  cases  these 
serpentine  grains  retain  perfectly  the  cleavage  and  the  repeated  twinning 
planes  of  the  dolomite. 

No.  30  is  a  white,  bedded  limestone  with  distant,  thin  partings  of  ser- 
pentine, probably  originally  an  actinolitic  limestone.  Traces  of  hornblende 
with  extinction  14°  could  be  seen. 

20.  ''Massive  garnet. — Westfield."  XIII,  No.  40, Massachusetts  Survey 
Collection. — This  is  a  granular  mixture  of  quartz,  garnet,  and  pyroxene,  and 
can  have  been  introduced  here  only  as  one  of  the  rocks  bordering  upon 
the  Atwater  serpentine  bed. 

21.  "Compact  scapolite  (?).— Westfield."  XIII,  No.  32,  Massachusetts 
Survey  Collection. — A  bluish- white,  translucent,  partly  sparry,  partly  cryp- 
tocrystalline  mass,  showing  the  distinct,  very  fine,  triclinic  striation  of  a 
plagioclase,  exactly  like  that  associated  with  the  serpentine  at  the  Chester 
emery  mine  and  at  the  Pelham  asbestos  quarry. 

MON  XXIX 8 


114       GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

22.  Enstatite-serpentine. — Westfield.  Prolonging  the  line  of  the  Atwater 
bed  in  Russell  southward,  it  is  found  that  many  large  bowlders  occur  where 
it  crosses  the  road  to  Grranville,  and  farther  south  an  immense  block  lies  in 
the  woods  on  the  hill  back  of  S.  Drake's  house,  in  the  west  parish  of 
Westfield,  which  is  made  up  of  very  large  enstatite  crystals  in  every  stage 
of  change  to  bastite,  and  the  whole  mass  is  exactly  like  that  described 
above  at  J.  Downey's,  in  West  Granville. 

Farther  south,  along  Munn's  brook,  where  it  cuts  a  deep  gorge  in 
Sodom  Mountain,  at  the  head  of  the  gorge,  near  the  house  of  H.  H.  Pur- 
chase, and  at  the  mouth  of  the  same,  are  many  great  bowlders  of  a  similar 
black  serpentine  with  large  crystals  of  enstatite  changing  or  changed  into 
bastite  or  white  talc.  All  these  occurrences,  to  this  last  by  Munn's  brook, 
are  so  similar  that  a  single  description  of  slides  cut  from  the  great  bowlder 
at  H.  H.  Purchase's,  Granville,  may  serve  for  them  all,  and  this  occurrence 
is  so  like  that  near  J.  Downey's,  in  West  Granville,  that  the  description  can 
be  brief,  as  I  shall  note  only  the  important  differences. 

Slides  of  the  freshest  enstatite  show  a  reddish-yellow  color  and  polarize 
brilhantly.  Some  of  them  contain  very  abundantly  the  stout,  straight 
black  rods;  in  others  they  are  as  rare  as  in  the  former  locality.  Magnesite 
in  rounded  grains  and  distinct  rhombohedra  is  found  abundantly  in  the 
freshest  enstatite,  apparently  as  a  primary  constituent.  A  qualitative 
examination  determined  the  absence  of  calcium.  With  cold  hydrochloric 
acid  fragments  of  the  serpentine  presented  no  change;  with  boiling  acid 
there  was  a  long-continued  effervescence,  and  there  remained  an  interlaced 
mass  of  altered  enstative  crystals. 

23.  "Diallage  in  serpentine. — Sodom  Mountain."  XIII,  No.  48,  Massa- 
chusetts Survey  Collection.  The  specimen  is  wanting  in  the  collection  at 
Amherst,  but  it  must  have  come  from  one  of  the  latter  localities  along  the 
gorge  of  Munn's  brook,  through  Sodom  Mountain,  and  must  have  been  an 
enstatite  and  not  a  diallage  rock,  the  latter  mineral  not  occurring  in  the 
serpentine  range. 

In  the  long  line  of  outcrops  from  Zoar  to  North  Blandford  the  serpen- 
tine is  characterized  by  deep  oil-green  colors,  marked  translucence,  and 
freedom  from  secondary  magnetite.  It  is  composed  of  fine  serpentine  blades 
mingled  with  softly  irised  films  of  talc,  and  still  contains  the  scattered  grains 


THE  CHESTER  AMPHIBOLITE  AND  SERPENTINES.  115 

of  hi"-lily  refractive  epidote,  which  have  passed  unchanged  from  the  parent 
rock,  and  often  show  traces  of  its  stratification.  It  would  seem,  then,  to  have 
been  derived  from  the  common  epidotic  hornblende-schist  (amphibolite) 
with  which  it  is  associated.  In  a  great  number  of  slides  no  trace  of  olivine 
or  enstatite,  or  of  the  structures  characteristic  of  these  minerals,  could  be 
detected  except  in  the  bowlders  from  Chester  (Massachusetts  Survey  Col- 
lection, XIII,  No.  53),  whose  exact  locality  can  not  be  determined,  and 
those  from  the  base  of  the  large  Middlefield  bed,  from  which  place  the 
Chester  bowlder  may  have  come.  The  presence  of  so  large  masses  of 
chi'omite  and  of  nickel  requires  explanation,  and  indicates  that  some  parts 
of  these  beds  were  once  chrysolitic.  The  specimen  labeled  XIII,  No.  43,  of 
the  Massachusetts  Survey  Collection,  from  Chester,  probably  from  the  south 
end  of  the  large  Middlefield  bed,  where  is  an  old  "  mine  "  of  this  ore,  is  a 
mass  of  chromite  50"™  on  a  side.  Moreover,  the  discovery  that  the  so-called 
quartz  pseudomorphs  from  the  Middlefield  bed  are  serpentine  pseudomorphs 
after  olivine^  must  receive  consideration  in  this  connection.  They  are,  how- 
ever, large,  perfectly  terminated  crystals,  some  of  which  have  broken  off  from 
the  walls  of  the  cavity  to  which  they  were  attached,  and  they  can  not  be 
taken  as  normal  idiomorphic  constituents  of  an  ultra  basic  eruptive.  They 
are  better  explained  as  fissure  minerals  in  a  crystalline  limestone,  like  the 
Snarum  crystals. 

I  conclude,  therefore,  that  nearly  all  of  these  serpentines  are  derived 
from  the  amphibolites,  and  find  the  stratigraphical  evidence  in  this  direction 
strengthened  by  the  lithological  evidence. 

Osborn's  quarry  at  Blandford  is  a  dividing  point  between  the  trans- 
lucent hornblende-serpentines  on  the  north  and  the  black  enstatite-sei-pen- 
tines  on  the  south.  To  the  east  of  the  central  steatite  bed,  which  is 
quarried,  is  the  isolated  and  unique  oli vine-serpentine  bed;  to  the  west  is 
the  equally  peculiar  sahlite-serpentine  bed. 

The  black  serpentine  and  dolomite  mass  which  forms  the  center  and  least 
changed  portion  of  the  central  steatite  bed  is  the  first  of  a  series  of  such 
deposits  which  locally  replace  the  amphibolite  in  its  further  progress  south. 
They  are  rare  and  subordinate  to  amphibolite  in  the  broadened  portion  of 
the  bed  across  West  Granville,  but  after  the  bed  has  bent  northward  at 
East  Granville  they  increase  in  relative  importance  and  are  associated  with 

1  See  BuU.  U.  S.  Geol.  Survey  No.  126,  1895,  p.  91. 


116 


GEOLOGY  OP  OLD  HAMPSHIEE  COUNTY,  MASS. 


considerable  beds  of  white  crystalline  limestone,  dolomite,  and  tremolite 
schist,  and  in  the  further  prolongation  of  the  bed  across  Russell  and  West- 
field  the  enstatite-serpentines  and  the  half-altered  beds  of  very  coarse 
enstatite  rock  associated  with  great  beds  of  crystalline  limestone  become 
entirely  predominant.  The  black,  fissile  amphibolites  accompany  the  ensta- 
tite-serpentine  beds  to  the  end. 

The  presence  of  dolomite  as  an  original  constituent,  both  as  inclusions 
in  the  unchanged  enstatite  and  in  the  interstices  of  the  enstatite  rock,  as 
well  as  in  great  beds,  indicates  the  derivation  of  the  whole  series  from  large 
beds  of  dolomitic  limestone.  The  subject  is  summarized  on  page  147,  after 
the  description  of  the  emery  bed. 

Below  is  given  a  table  of  all  the  analyses  of  serpentines  known  to  me 
from  this  area.  The  material  used  in  the  analyses  1  to  6  was  furnished  by 
the  author,  and,  excepting  2  and  9,  great  care  was  taken  to  detect  all  the 
rarer  constituents,  especially  nickel,  cobalt,  and  chromium. 

Analyses  of  serpentines. 

[Nos.  1,  3,  5, 6,  and  8,  by  Mr.  George  Steiger,  in  the  laboratory  of  the  United  States  Geological  Survey ;  No.  3,  by  Miss 
H.  P.  Cook,  instructor  in  chemistry  in  Smith  College ;  No.  9,  by  Prof.  C.  IT.  Sbepard ;  No.  2,  by  Melville,  quoted  from  Dana's 
Manual,  p.  672;  Nos.  4, 7,  and  11,  by  Dr.  W.  F.  HUlebrand,  of  the  United  States  Geological  Survey.] 


1. 

2. 

3. 

4. 

5. 

6. 

7. 

8. 

9. 

10. 

11. 

Si02    

40.42 

None. 

1.86 

2.75 

4.27 

.43 

.28 

.53 

Trace. 

Trace. 

.66 

None. 

35.95 

}      .16 

44.22 

40.27 

38.62 

None. 

.35 

3.44 

3.99 

39.14 

None. 

1.18 

4.46 

3.14 

33.87 

None. 

.77 

2.81 

4.25 

40.77 

None. 

1.16 

3.56 

1.47 

37.82 

Trace. 

.61 

7.92 

1.15 

44.16 

7.05 

36.94 

Trace. 

.50 

6.04 

1.94 

54.04 

None. 

.52 

1.51 

3.90 

TiOj   

AI2O3 

.53 
6.61 

}5.74{ 

FeO 

CrnO^ 

.39 
.21 

.33 
.47 
Trace. 
None. 
None. 
None. 
41.45 

1  None. 

.38 

\      .33 

.04 
None. 
None. 
38.67 

None. 

.28 

.09 
None. 

39.37 

\      .14 

Trace. 

.49 

12.48 

.19 
.45 
.05 

.33 
.40 

None. 

Trace. 

None. 

None. 

38.35 

None. 

.14 
.23 

.11 
None. 
None. 
34.40 

.08 

NiO 

CoO 

MnO 

.10 
.40 

CaO            

None. 
None. 
37.94 

JTrace. 

37.44 

BaO          

MgO         

37.54 

40 

40.61 

,      .08 

1      .10 

Trace. 

.36 

10.91 

KjO    

NajO 

Li  0 

H2O— 100 

H2O+IOO 

.21 

10.51 

Trace. 

Trace. 

1.44 

.36 
11.26 

.69 
13.61 

.34 

9.48 

None. 

.02 
None. 

.38 

7.00 

.20 

Trace. 

10.82 

.75 
12.50 

11 

.71 

12.07 

.20 

Trace. 

1.85 

.70 
3.07 

None. 
1.32 

P„0= 

Trace. 
.62 

Trace. 
None. 

Trace. 

C02 

99.47 

100.  52 

100.31 

100.  08 

100. 01 

99.  42     100.  08 

99.38 

99.65 

99.33 

100.  02 

No.  1.  Eicb,  dark-green  serpentine.    Eowe.    Quarry  near  E.  King's. 
No.  2.  Picrolite.    Florida. 

No.  3.  Straw-yellow,  fibrous  serpentine,  glazed,  enveloping  olivine  pseudomorpbs.    Middlefleld.    From  the  speci- 
men figured  in  Bull.  U.  S.  Geol.  Survey  No.  126,  PI.  I. 


THE  CHESTER  AMPHIBOLITE  AND  SEEPENTINES.  117 

No.  4.  Normal  dark-green^  slightly  oily  eerpeutino,  from  the  ceuter  of  the  large  Middlefield  bed,  taken  from  where 
the  road  crosses  the  Cho3t«r-Middlefiold  line. 

No.  5.  Black-groen  serpentine,  weathering  to  pale  niekel-greon,  with  much  chromite.  North  Blandford.  From 
"The  Crater." 

No.  0.  Gray,  splintery  serpentine  enveloped  in  talc.    Chester.    From  the  east  wall  of  the  old  mine. 

No.  7.  Serpentine  from  the  lower  bed  at  Osborn's  quarry,  Blandford,  which  still  retains  the  cleavage  of  sahlite  and 
iB  places  considerable  remnants  of  the  mineral. 

No.  8.  Enstatite  changed  to  serpentine.    Granville.    H.  Cooley's. 

No.  9.  Black  serpentine  with  bastite.    Eussell. 

No.  10.  Black  serpentine  containing  marmolite  (bastite).    Kussell.    Atwater's  quarry. 

No.  11.  Slightly  altered,  nearly  colorless  enstatite,  from  Downey's,  in  Granville  j  added  for  comparison. 

The  constant  content  of  nickel,  cobalt,  and  chromium  in  all  these 
analyses  where  it  has  been  searched  for  is  very  interesting  and  may  be 
taken  as  an  indication  of  the  eruptive  origin  of  the  whole  series,  which 
would,  however,  involve  the  derivation  of  large  beds  of  white  crystalline 
limestones,  both  dolomitic  and  quite  purely  calcareous,  from  the  same 
basal  eriTptive  rocks. 

THE  CHESTER  EMERY  BED. 
HISTORY  OF  DISOOVEKY  AND  WORKING-  OP  THE  BED. 

Not  the  least  interesting  element  in  the  peculiar  geology  of  the  west- 
ern part  of  Chester  is  the  great  magnetite-emery  bed  which  lies  along  the 
upper  (eastern)  line  of  junction  of  the  hornblende-schist  with  the  sericite- 
schist  and  extends  from  the  Westfield  (better  Agawam)  River  southward 
nearly  to  the  south  line  of  the  town  and  nearly  as  far  as  the  great  horn- 
blendic  band  retains  its  maximum  thickness. 

The  history  of  the  discovery  of  this  bed  has  often  been  told,  and 
deserves  to  be  retold.  The  credit  of  the  discovery  and  its  first  announce- 
ment belongs  to  Dr.  C.  T.  Jackson.  I  remember  how  Professor  Shepard, 
when  taking  my  college  class  through  the  cabinets  in  1865,  stopped  at  the 
old  State  geological  collection  made  by  President  Hitchcock  dm-ing  his 
survey  of  Massachusetts,  and  took  down  the  specimen  of  magnetite  col- 
lected from  the  Chester  bed  and  pointed  out  to  us  the  emery  which  it 
contained,  to  show  us  how  near  Dr.  Hitchcock  had  been  to  ntimbering  this 
among  his  many  discoveries.  Dr.  Hitchcock  had  described  several  beds  of 
magnetite  for  the  first  time  in  his  final  report.^  They  were  located  in  the 
western  part  of  Chester,  in  hornblende-schist,  and  none  of  them  exceeded 
1  foot  in  width. 

For  the  next  events  in  the  history  of  the  locality  I  must  have  recourse 

1  Geology  of  Massachusetts,  1844,  pp.  194,  612. 


118       GEOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 

to  the  "  Biogi-apliical  Sketch"  of  Dr.  Herman  S.  Lucas,  of  Chester,  inserted 
at  the  end  of  the  town  history  of  Chester.^  From  the  well-known  manner 
in  which  this  book  was  compiled,  and  from  internal  evidence  in  the  sketch 
itself,  one  is  led  to  attribute  to  it  somewhat  of  an  autobiographical  character. 
The  paragraphs  bearing  upon  the  history  of  the  emery  beds  are  as  follows : 

But  perhaps  tlie  most  remarkable  event  in  his  career  was  the  discovery  of  what 
was  for  some  time  supposed  to  be  a  vast  deposit  of  iron  ore  in  the  mountains  around 
Chester.  This  occurred  in  1856,  and  arrangements  were  at  once  made  for  the  opening 
and  working  of  the  mine ;  and  in  the  course  of  about  one  year  1,200  tons  of  mineral 
were  taken  out  and  transported  to  the  furnaces  of  Stockbridge,  Lenox,  and  Hudson. 

The  financial  crisis  of  1857  compelled  a  discontinuance  of  the  business,  and  it 
was  not  renewed  until  1863.  In  the  last-mentioned  year,  in  company  with  his  brother, 
John  B.  Lucas,  and  Henry  D.  Wilcox,  he  resumed  the  business.  A  blast  furnace  and 
forge  were  erected  in  Chester  and  the  manufacture  of  iron  was  commenced,  but  the 
ore  proved  somewhat  intractable  and  the  results  were  not  satisfactory.  In  the  mean- 
time the  Doctor  made  a  more  thorough  examination  of  the  mineral,  and  on  the  6th  of 
September,  1864,  discovered  that  it  contained  a  large  percentage  of  emery,  a  mineral 
hitherto  nearly  unknown  in  the  United  States;  in  fact,  this  is  believed  to  have  been 
its  first  discovery  in  America. 

Coming  at  a  time  when  the  country  was  engaged  in  a  terrible  war  with  internal 
enemies,  the  discovery  was  doubly  valuable.  Heretofore  the  emery  used  in  this  coun- 
try had  been  imported  from  the  Turkish  dominions,  and  as  the  English  and  French 
Goverments  had  a  monopoly  of  the  mines  near  Smyrna,  in  Asia  Minor,  and  on  the 
Greek  island  of  Naxos,  in  the  archipelago,  the  United  States  Government  was 
debarred  from  procuriiig  its  necessary  supply,  except  under  unusual  difflculties.  In 
this  dilemma  the  Chester  emery  was  utUized  and  the  Government  works  were 
supplied  from  it  for  a  considerable  time. 

This  mineral  had  repeatedly  been  examined  by  various  scientific  gentlemen,  and 
specimens  were  placed  in  the  collections  at  Amherst  College  and  in  that  made  by 
Professor  Hitchcock  for  the  State  and  labeled  magnetite. 

In  1868  Dr.  Lucas,  with  Messrs.  Charles  Alden  and  H.  D.  Wilcox,  formed  what 
was  known  as  the  Hampden  Emery  Company,  and  erected  a  mill  on  the  river  below 
Chester  village  for  the  manufacture  of  emery. 

In  1874  questions  touching  the  ownership  of  the  mines  involved  the  Doctor  in 
litigation,  which  necessitated  a  change  in  his  business,  and  from  that  time  he  has 
obtained  his  mineral  mostly  from  the  Turkish  mines. 

The  Doctor  continued  in  business  in  his  own  name  until  May  1,  1878,  when 
Nathan  Harwood  became  associated  with  him. 

The  importance  of  this  discovery  is  well  illustrated  by  the  remark  of  a  great 
English  statesman,  that  "The  discovery  of  an  emery  mine  was  of  more  value  than 
that  of  many  gold  mines." 


'History  of  the  Connecticut  in  Massachusetts,  vol.  2,  p.  1064;  Lewis  H. Evert,  Philadelphia,  1879. 


THE  CHESTEE  EMERY  BED.  119 

I  thiuk  that  one  may  hazard  the  conjecture  that  the  last  sentence  in  the 
above  was  quoted  from  memory,  and  thus  rather  imperfectly,  from  the  opening 
sentence  of  the  article  cited  next  below,  though  there  is  no  other  mdication 
that  the  biographer  of  Dr.  Lucas  was  acquainted  with  the  part  taken  by  Dr. 
Jackson  in  the  discovery  of  emery  at  Chester.  It  will  be  well,  therefore, 
to  let  the  account  of  the  matter  given  by  Dr.  Jackson  himself  follow:^ 

It  has  been  said  in  England  that  "  a  good  mine  of  emery  is  worth  more  to  a  man- 
ufacturing people  than  many  mines  of  gold."  Such  being  the  case,  it  affords  me  great 
pleasure  to  be  able  to  announce  the  discovery  of  an  inexhaustible  bed  of  the  best 
emery  in  the  world  in  the  middle  of  the  State  of  Massachusetts,  in  Chester,  Hampden 
County  quite  near  to  the  Western  Railroad,  which,  with  its  ramifications,  leads  to 
the  largest  armories  and  manufactories  of  metallic  articles  in  this  and  the  adjacent 

States.  „  ... 

For  more  than  two  years  the  existence  of  important  beds  of  magnetic  iron  ore, 
originally  discovered  by  Dr.  H.  S.  Lucas,  has  been  known,  and  endeavors  were  made 
by  that  gentleman  to  organize  a  company  for  the  purpose  of  smelting  these  ores.  In 
consequence  of  this  agitation  I  was  employed  by  John  B.  Taft,  esq.,  on  the  19th  of 
October,  1863,  to  examine  the  locality  and  to  make  report  of  my  results  to  him. 

On  examination  of  my  specimens  of  minerals  after  returning  to  Boston,  and  my 
notes  for  sectional  profiles  of  the  rocky  strata  containing  the  iron  ore,  I  found  that 
the  minerals  margarite  and  chloritoid,  in  talcose,  hornblende,  and  mica  slate  rocks, 
indicated  the  occurrence  of  emery,  the  association  of  the  rocks  and  minerals  being 
identical  with  conditions  known  to  exist  in  the  localities  of  emery  in  Asia  Minor. 

I  therefore  called  the  attention  of  the  owners  of  the  property  to  these  facts,  and 
directed  that  search  be  made  for  emery,  and  that  every  mineral  resembling  it  should 
be  sent  to  me  for  examination.  Little  attention  was  paid  to  this  prediction  at  the 
time,  nor  until  I  had  invited  Dr.  Lucas,  who  resides  in  Chester,  by  personal  represen- 
tations and  solicitations,  to  make  the  required  search,  the  characters  of  emery  being 

fally  described  to  him.  . 

On  his  return  to  Chester  he  soon  learned  that  the  miners  were  complaming  of 
the  great  hardness  of  the  supposed  iron  ore,  and  that  no  less  than  forty  drills  were 
dulled  in  boring  a  single  hole  for  blasting.  He  then  sent  me  pieces  of  this  hard  rock, 
in  the  belief  that  it  was  the  emery  I  had  predicted.  On  examination  it  was  found  to 
scratch  quartz  and  topaz  readily  and  to  have  all  the  properties  of  emery.  A  chemical 
analysis  proved  it  to  be  identical  with  the  emery  of  Naxos. 

The  owners,  resident  in  Boston,  being  notified  of  this  discovery,  went  with  me  to 
the  locality  on  the  11th  of  October  last,  when  a  full  exploration  of  the  premises  was 
made  There  are  several  large  beds  of  rich  magnetic  iron  ore  at  this  locality,  and  the 
emery  being  magnetic  (as  it  always  is)  has  caused  it  to  be  mistaken  for  magnetic  iron 
ore,  and  many  tons  of  it  had  been  smelted  wjth^the_c^nate^  iron  and  hematite  in 

:^^^s^J  of  Emery  in  di^ster^Blachusetts,  by  Charles  T.  Jackson,  M.D.,  Geologist  and 
State  Assayer:  Am.  Jour.  Sci.,  2d  series,  Vol.  XXXIX,  May,  1865,  p.  87. 


120  GEOLOGY  OF  OLD  HAMPSHIEB  COUNTY,  MASS. 

the  Berkshire  County  irou  .furnaces  without  a  suspicion,  notwithstanding  its  refrac- 
tory nature,  that  the  ore  was  emery,  with  only  a  small  admixture  of  iron  ore. 

The  mineralogical  and  geological  data  of  the  article  are  quoted  under 
"Emery"  in  the  Mineralogical  Lexicon  covering  the  field  of  this  mono- 
graph^ and  under  the  general  description  of  the  vein  (p.  135).  The  conclu- 
sion of  the  article  is  as  follows: 

It  may  be  proper  to  add  that  John  B.  Taft,  esq.,  of  Boston,  in  behalf  of  his 
associates,  owners  of  the  emery  mine,  has  the  sole  management  of  the  business  con- 
nected with  the  mine. 

I  would  express  my  obligations  to  Mr.  J.  L.  Smith  for  the  valuable  information 
contained  in  his  articles  on  the  emery  of  Asia  Minor  and  on  the  associated  minerals 
of  the  emery  localities  published  in  Vols.  X  and  XI  of  this  journal;  also  to  Dr.  H.  S. 
Lucas,  of  Chester,  for  kind  assistance  in  the  field.^ 

It  seems  thus  that  the  veins  became  known  to  Dr.  Hitchcock  between 
1836  and  1841,  and  that  Dr.  Lucas,  who,  as  an  ardent  student  of  the  min- 
eralogy of  his  native  town,  was  doubtless  acquainted  with  Dr.  Hitchcock's 
published  work,  examined  the  beds,  became  convinced  of  their  economic 
value  and  began  work  upon  them  in  1856.  He  renewed  his  work  in  1863, 
bat  as  an  iron  industry  it  did  not  prove  profitable,  and  the  property  passed 
into  the  hands  of  a  Boston  company  represented  by  Mr.  John  B.  Taft,  and 
in  which  Dr.  Lucas  was  interested. 

Largely,  perhaps,  on  account  of  the  refractory  nature  of  the  ore.  Dr. 
Jackson  was  employed  to  examine  the  mine,  and,  relying  upon  the  earlier 
investigations  of  J.  Lawrence  Smith,  predicted  the  occurrence  of  emery 
from  the  associated  minerals  and  urged  Dr.  Lucas  to  search  for  it. 

In  the  meantime  the  miners  had  practically  discovered  the  emery, 
much  to  their  sorrow,  and  I  have  been  informed  bv  two  who  Avorked  in  the 
mine  at  the  time  that  they  were  well  persuaded  that  the  brown  mineral  was 
what  dulled  their  tools  and  were  accustomed  to  call  it  emery.  Armed  with 
this  practical  and  scientific  information.  Dr.  Lucas  investigated  the  ore  anew, 
determined  the  emery,  and  sent  the  specimens  to  Dr.  Jackson,  upon  which 
he  made  his  mineralogical  tests  and,  most  important  of  all,  his  chemical 
analyses.^ 

1  Bull.  U.  S.  Geol.  Survey  No.  126,  under  "Corundum." 

2  In  a  recent  report  of  an  interview  with  Dr.  Lucas  (Springfield  Eepublioan,  "Another  vein  of 
corundum,"  December  12,  1895)  the  history  of  the  discovery  is  repeated  much  more  nearly  in 
accordance  with  the  account  of  the  matter  I  have  given  than  with  the  biographical  sketch  quoted 


THE  CHESTER  EMERY  BED.  121 

This  o-ave  rise  to  the  emery  mining',  and,  in  1868,  to  the  formation  of 
the  Hampden  Emery  Company,  in  which  Dr.  Lucas,  Mr.  S.  A.  Bartholomew, 
of  Blandford,  and  Dr.  Jackson  were  interested.  A  few  years  later  this  com- 
pany deeded,  in  apparent  good  faith,  what  they  supposed  to  be  the  main 
vein,  of  which  they  had  previously  bought  the  mining  right,  to  the  Chester 
Iron  Company,  afterward  the  Chester  Emery  Company,  a  stock  company 
controlled  by  Mr.  James  T.  Ames,  of  Chicopee,  Massachusetts,  of  the  Ames 
Manufacturing  Company. 

The  older  company  deeded  "commencing  in  the  middle  of  the  vein  of 
iron  ore  and  running  at  right  angles  to  the  same  5  rods,  thence  parallel  to 
the  same  to  its  south  end,  thence  10  rods  at  right  angles  to  the  same,  thence 
parallel  to  the  same  to  the  north  end,  thence  5  rods  at  right  angles  to  the 
same  to  the  place  of  beginning,  being  about  4  acres."  The  new  company 
went  to  work  upon  its  purchase,  while  the  old  company  continued  to  work 
ujDon  a  vein  farther  west,  which  it  still  held.  In  a  short  time  it  was  found 
that  the  new  company  was  working  upon  a  line  of  bowlders  derived  doubt- 
less from  the  true  deposit  to  the  west,  upon  which  the  old  company  was 
still  working  vigorously. 

Theretipon  arose  an  important  lawsuit,  the  Chester  Company  claiming 
the  true  vein,  while  the  old  company  claimed  that  a  blunder  had  been  made 
by  all  parties,  and  that  the  attempt  to  apply  the  deed  to  the  western  vein 
would  give  7  acres  instead  of  4.  After  protracted  litigation  the  case  was 
decided  for  the  purchasers,  and  the  vein  came  into  the  hands  of  the  Chester 
Company  and  was  worked  by  it,  extensive  buildings  being  erected  and 
expensive  machinery  obtained.  In  1879  thirty-five  men  were  employed 
and  210  tons  of  emery  were  produced,  valued  at  $20,000.^ 

The  mine  was  worked  apparently  without  much  profit,  since  in  1883, 
after  the  death  of  Mr.  Ames,  the  whole  property,  said  to  have  cost  above 
$80,000,  was  pm-chased  by  Dr.  Lucas  for  a  sum  reported  to  be  about 
$12,000. 

On  the  adverse  issue  of  the  lawsuit  Dr.  Lucas  had,  with  customary 
energy,  turned  his  attention  to  the  Naxos  emery,  and  curiously,  from  the 

above.     Dr.  Lucas  here  claims  to  have  discovered  the  emery  in  1864;  it  is  said  that   the  miners 
"could  make  very  little  headway  against  the  rocks,  which,  they  told  Dr.  Lucas,  were  so  hard  that 
they  could  not  keep  their  tools  sharp;"  that  Dr.  Jackson  told  Dr.  Lucas  that  the  margarite  was 
sometimes  found  with  emery,  and  "  it  was  this  that  gave  Dr.  Lucas  his  clew." 
'Hist.  Conn.  Valley,  Vol.  II,  p.  1063. 


122  GEOLOGY  OF  OLD  HAMPSHIEB  COUNTY,  MASS. 

fact  that  the  crude  emery  could  be  entered  free  while  the  manufactured 
article  was  highly  taxed,  and  from  the  further  fact  that  sailing  vessels  trading 
with  the  Mediterranean  were  compelled  to  return  in  ballast  and  were  thus 
willing  to  deliver  the  crude  emery  in  New  York  with  little  or  no  charge 
for  freight,  he  was  able  to  create  a  lucrative  industry.  Latterly  his  sup- 
plies have  been  drawn  principally  from  the  Southern  States. 

In  1883  no  work  was  in  progress  except  at  the  north  mine,  where  six 
men  were  employed,  and  during  the  year  even  this  work  was  stopped.  In 
1890  the  old  mine  was  reopened  and  has  since  been  worked  continuously, 
and  the  working  has  reopened  the  area  where  the  fine  diaspore  occurs. 
In  1894  an  adit  was  driven  into  the  hill  on  the  north  side  of  the  road  along 
the  eastern  wall  of  the  vein. 

In  1865  Prof  C.  U.  Shepard  published  a  report  upon  the  mine,^  mainly 
mineralogical,  but  containing  notes  on  the  geology  of  the  vein.  The  repoi-t 
was  published  in  such  form  that  it  is  not  now  obtainable,  and  it  seems  to 
me  desirable  that  it  be  published  in  full  in  this  place. 

A  Description  of  the  Emery  Mine  op  Chester,  Hampden  County,  Mass. 
U.  S.  A.,  BY  Charles  Upuam  Shepard,  Massachusetts,  professor  of  Natural 
History  in  Amherst  College.  (Printed  by  Taylor  &  Francis,  Eed  Lion  Court, 
Fleet  street,  London,  1865.) 

Correction. 

The  statement  in  this  report  respecting  the  suggestion  of  Dr.  Lawrence  Smith 
was  based  upon  a  misapprehension  of  the  facts. 

The  whole  credit  of  the  emery  discovery  at  Chester  is  due  to  Dr.  C.  T.  Jackson, 
who  made  a  personal  examination  of  the  locality  with  reference  to  the  iron  ore,  and 
from  his  knowledge  of  the  minerals  associated  with  emery  inferred  the  existence  of 
that  mineral  in  this  locality  and  advised  an  examination  for  the  purpose  of  ascer- 
taining whether  it  did  not  exist  there.  Dr.  Jackson,  among  other  sources  from  whence 
he  had  derived  information  on  the  general  subject,  had  in  his  possession  the  articles  of 
Dr.  Smith  on  the  emery  of  Asia  Minor  and  on  the  associated  minerals,  published  in 
Vols.  X  and  XI  of  the  American  Journal  of  Science.  But  Dr.  Smith  had  no  knowl- 
edge of  the  Chester  mine  or  minerals  until  after  the  published  reports  of  the  discovery 
of  the  emery  by  Dr.  Jackson. 

Charles  Upham  Shepard. 
Boston,  November  7, 1865. 

1 A  Description  of  the  Emery  Mine  of  Chester,  Hampden  County,  Massachusetts.     16  pages.    London. 


THE  CHESTER  EMERY  BED.  123 


Emkry  Mine. 


The  discovery  of  this  mine  so  recently  as  the  autuma  of  1864  within  the  bound- 
aries of  the  State  of  Massachusetts,  where  so  much  attention  has  been  given  to 
mineralogy  and  geology,  seems  somewhat  singular;  the  more  so,  perhaps,  as  its  occur- 
rence is  so  near  the  machine  shops  and  armories  in  which  the  consumption  of  emery 
is  very  considerable.  Among  the  reasons  of  its  delayed  discovery  may  be  adduced 
its  situation  in  a  mountainous  and  thinly  inhabited  section,  which  until  recently  has 
attracted  but  little  scientific  or  economic  notice.  Emery,  moreover,  being  itself  rich 
in  irou  and  largely  associated  with  magnetic  iron  ore  (magnetite),  is  extremely  liable 
to  be  confounded  with  the  latter  substance,  and  this  was  the  case  with  it  at  Chester, 
whence  about  1,000  tons  were  raised  for  iron  making  before  its  true  nature  was  ascer- 
tained. The  discovery  would  probably  have  been  still  longer  deferred  but  for  the 
happy  suggestion  of  Prof.  J.  Lawrence  Smith,'  that  the  occurrence  of  the  margarite 
at  Chester  should  lead  to  a  direct  search  for  emery,  this  mineral  being  one  of  the 
invariable  concomitants  of  that  highly  important  substance.  This  suggestion  was  at 
once  successfully  acted  upon  by  Dr.  Lucas  and  jST.  C.  Sawyer,  esq. 

The  mine  is  situated  nearly  in  the  center  of  the  Green  Mountain  chain  as  it 
traverses  the  western  border  of  the  State,  at  a  point  not  far  from  halfway  between 
the  Connecticut  and  Hudson  rivers.  It  is  included  in  the  metamorphic  series  of  rocks, 
here  consisting  of  vast  breadths  of  gneiss  and  mica-slate,  with  considerable  inter- 
polations of  talcose  slate  and  serpentine.  The  general  direction  of  the  stratification 
is  N.  20°  B.  and  S.  20°  W.,  the  relation  to  the  horizon  varying  from  vertical  to  a  dip 
of  from  75°  to  80°,  sometimes  east,  sometimes  west. 

The  immediate  vicinity  of  the  mine  presents  a  succession  of  lengthened  rocky 
swells  with  rather  precipitons  sides,  having  summits  between  750  and  1,000  feet  above 
the  level  of  the  principal  streams  by  which  the  hills  are  traversed.  The  longer  axis 
of  the  elevations  generally  coincides  with  the  direction  of  the  strata. 

The  emery  vein  traverses  in  an  unbroken  line  the  crests  of  two  of  these  adjoining 
mountains  and  scarcely  deviates  as  a  whole  from  the  magnetic  meridian.  Each  moun- 
tain is  estimated  to  have  a  length  of  2  miles,  thus  giving  4  miles  extent  to  the  metallif- 
erous stratum,  for  such  it  may  truly  be  called,  consisting,  as  it  does,  so  largely  of  the 
metals  iron  and  aluminium.  The  Westfleld  River,  here  a  small  stream  of  about  4  rods 
in  width,  flows  directly  across  the  northern  end  of  the  vein,  while  a  branch  of  the  same 
river,  having  half  its  size,  separates  the  two  mountains  and  very  nearly  divides  the 
vein  into  two  equal  portions.    The  height  of  each  mountain  is  estimated  at  750  feet. 

The  emery  vein,  whose  average  width  may  be  taken  as  4  feet,  is  situated  near 
the  junction  of  the  great  gneiss  formation  constituting  the  western  flank  of  the 
mountains,  with  the  mica-slate  forming  their  eastern  slope.  To  speak  more  exactly, 
however,  it  lies  just  within  the  gneiss,  having  throughout  a  layer  of  this  rock  from 
4  to  10  feet  in  thickness  for  its  eastern  wall.  Nor  does  the  mica-slate  advance  quite 
up  to  this  outside  layer  of  the  gneiss,  but,  in  place  thereof,  an  extensive  intrusion  of 


1  To  Dr.  Smith  we  are  indebted  for  the  first  scientific  survey  of  the  emery  mines  of  the  Grecian 
Archipelago  and  Asia  Minor. 


124       GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

the  talcose  slate  occixrs,  having  an  average  thickness  of  20  feet  on  the  South  Mountain 
and  widening  out  on  the  North  Mountain  to  a  breadth  of  nearly  200  feet  as  it  reaches 
the  terminus  of  the  vein  in  the  bed  of  the  Westfield  Eiver. 

The  gneiss,  more  especially  in  the  vicinity  of  the  vein,  is  a  very  peculiar  rock. 
It  abounds  in  thick  seams  of  a  coarsegrained  very  black  and  shining  hornblende, 
and  where  this  is  not  found  it  is  much  veined  and  penetrated  by  epidote.  The 
stratification  is  much  contorted  also,  and  when  the  surface  of  the  formation  happens 
to  be  weathered  or  water-worn  its  basseting  edges  strikingly  resemble  in  color  some 
of  the  serpentine  marbles.  It  is  also  noticeable  that  in  it  quartz  is  everywhere 
singularly  deficient.  Traces  of  a  white  calcareous  spar  (calcite)  are  now  and  then 
visible  upon  the  joints  of  the  gneiss,  with  occasional  specks  of  yellow  copper,  together 
with  malachite  stains,  but  no  corundum,  emery,  or  magnetite  particles  have  thus  far 
been  detected  as  constituents  of  the  gneiss  itself.  It  is  quite  otherwise,  however,  with 
the  talcky  rock  exterior  to  the  wall  of  gneiss,  for  that  formation  in  all  its  different 
varieties  of  talcose  slate,  soapstone,  chloritic  aggregates  (with  included  seam  of 
indianite),  talcky  dolomite,  etc.,  which  together  constitute  the  stratum  separating  the 
gneiss  from  the  mica-slate,  contain  here  and  there  disseminated  grains  of  either  emery, 
corundum,  or  magnetite,  but,  like  the  gneiss  again,  are  strikingly  free  from  quartz  or 
uncombined  silica  in  any  of  its  forms.  Indeed,  this  generally  abundant  substance  is 
altogether,  wanting,  not  only  in  the  emery  vein,  but  in  the  talcose  formations  consti- 
tuting its  eastern  boundary.  It  makes  its  appearance,  however,  in  abundance  in  the 
mica-slate  as  soon  as  the  talcose  rocks  are  passed,  showing  itself  not  only  as  the  usual 
constituent  of  the  slate,  but  in  more  or  less  continuous  seams  from  a  few  inches  thick 
up  to  above  6  inches  and  sometimes  a  foot  in  width.  Where  the  seams  are  thin  and 
discontinuous  the  included  masses  thin  out  at  each  end  before  disappearing,  the  sharp 
edges  being  curved  in  opposite  directions  so  as  to  form  frequent  white  patches  upon 
the  surface  of  the  rock  in  the  shape  of  the  letter  S.' 

Corundum  and  emery  (the  former  consisting  of  pure  alumina  and  the  latter  of 
the  same  earth  in  combination  with  the  protoxide  of  iron),  have  been  found  hitherto 
almost  exclusively  in  carbonate  of  lime  (marble  or  saccharoidal  limestone),  from  the 
substance  of  which  as  a  medium  or  vehicle  free  from  silica  they  were  precipitated  in 
crystals,  nodular  masses,  or  veins.  Here,  however,  carbonate  of  lime  is  wanting  (if  we 
except  a  partial  development  of  impure  dolomite  in  one  place  at  the  top  of  the  South 
Mountain) ;  but  a  parent  rock  or  menstruum  for  the  formation  of  corundum  and  emery 
is  supplied  in  a  talcose  slate  series  equally  deficient  in  free  silica,  this  being  a  compound 
which,  if  coexistent  with  alumina  and  protoxide  of  iron,  would  seem  to  be  incompatible 
with  the  formation  of  either  corundum  or  emery,  inasmuch  as  under  the  play  of  the 
ordinary  chemical  affinities,  several  very  different  species  would  be  more  likely  to  result.^ 

'  It  is  in  the  princij)al  veins  of  this  white  quartz  that  very  large  crystals  of  ilmenite  (washing- 
tonite)  were  found  at  one  spot  vrithin  a  mile  from  the  northern  end  of  the  vein. 

^An  analogous  abeyance  of  quartz  characterizes  the  aluminous  group  of  the  spinels,  the  occur- 
rence of  which  is  much  restricted  to  limestone  and  talcose  slate ;  and  since  alumina  is  rarely  abundant, 
even  in  granular  limestone  and  talcose  slate,  we  appear  to  have  an  explanation  of  the  general  scarcity 
of  the  corundom  and  spinel  species  in  the  mineral  kingdom. 


THE  CHESTER  EMERY  BED.  127 

particles  not  exceeding  in  size  those  of  certain  varieties  of  steel  or  flne-grained  cast 
iron.  The  fracture  is  effected  with  the  greatest  diHiculty,  and  takes  place  as  readily 
in  one  direction  as  another.  The  surface,  moreover,  has  an  exceedingly  hard  feel. 
Its  color  is  a  darker  brown  than  that  of  the  preceding  varieties.  It  also  presents  in 
some  specimens  a  faint  violet-blue  tarnish.  It  has  often  been  mistaken  for  magnetite, 
though  its  harshness  of  feel  and  verydiflacult  frangibility  easily  distinguish  its  masses 
from  that  ore.  It  has  a  tendency  to  occur  throughout  the  vein  in  wedge-shaped,  con- 
torted masses,  as  well  as  in  elliptical  balls  of  all  sizes,  from  a  few  pounds  weight  up 
to  a  hundred  pounds. 

{d)  Emery  magnetite. — This  is  a  massive  magnetite  containing  a  variable  intermix- 
ture of  emery.  It  closely  resembles  magnetite,  but  it  is  distinguished  by  its  superior 
hardness,  its  purplish  tarnish,  and  more  difScult  frangibility.  It  does  not  appear  to 
be  abundant,  though  it  is  often  liable  to  be  met  with  throughout  the  course  of  the 
vein. 

(e)  Stony  emery. — This  in  general  is  the  chloritoidal  rock  or  substance  of  the  vein 
in  places  where  it  is  not  replaced  by  one  of  the  preceding  varieties.  It  is  a  slaty, 
tough,  greenish-gray,  rather  heavy  aggregate,  containing  everywhere  flne-grained 
emery  in  proportions  varying  between  10  and  20  per  cent.  Other  minerals  also  are 
present  occasionally,  such  as  tourmaline,  epidote,  margarite,  ottrelite,  magnetite,  etc. 
A  variety  of  stony  emery  in  thin,  highly  contorted,  schistose  layers  enveloping  the 
compact  emery  frequently  presents  itself.  Its  color  is  a  delicate  greenish  white,  and 
it  is  often  interlaminated  by  seams  of  pinkish  margarite— the  entire  aggregate  being, 
nevertheless,  rich  in  emery. 

2.  Magnetite. 

ISext  in  abundance  among  the  constituents  of  the  vein  stands  the  present  species, 
that  richest  and  most  precious  of  all  the  ores  of  iron.  Its  composition  being  so  strictly 
accordant  with  that  of  emery,  their  joint  occurrence  would,  on  chemical  grounds,  be 
looked  for  almost  as  a  matter  of  course.  Like  the  emery  itself,  it  here  occurs  massive, 
thin-veined,  granular,  and  disseminated.  The  massive  variety  is  found  perfectly 
pure  and  unmixed,  having  a  structure  between  the  coarse-grained  (shot  ore)  of  the 
Lake  Champlain  region  and  the  finegrained,  compact  ore  of  Franconia  and  Danne- 
mora,  Sweden.  It  sometimes  exhibits  in  the  fracture  a  slightly  purplish  tint  not 
observable  in  any  other  magnetite  with  which  I  am  acquainted.  It  is  also  a  shade 
blacker  than  most  magnetites.  It  is  wholly  free  from  pyrites  and  all  traces  of  rust, 
and  consequently  is  bright  and  fresh  in  luster  throughout.  It  is  magnetic  with  polar- 
ity, but  does  not  give  rise  to  examples  of  the  native  magnet.  It  presents  itself  in 
considerable  quantity  at  several  places  on  the  course  of  the  vein.  For  example,  at 
the  top  of  the  North  Mountain  it  constitutes  a  continuous  seam  from  10  to  15  inches 
thick  in  a  chloritoidal  vien,  itself  4  or  5  feet  wide,  and  made  up  of  the  disseminated 
variety,  presently  to  be  mentioned.  This  vein  of  magnetite  forks  off  from  the  great 
emery  vein  on  its  eastern  side  at  an  angle  of  about  30°  and  then  pursues  its  course 
between    the   talcose   slate    strata,  within  which  it  has    already  been  opened  for 


128  GEOLOGY  OP  OLD  HAMPSHIRE  COUNTY,  MASS. 

10  or  12  yards,  having  an  easterly  dip  of  70°;  and  thence  continues  for  an  undeter- 
mined distance,  the  surface  of  the  ground  not  yet  having  been  cleared  of  loose  rocks 
and  of  trees  in  such  a  manner  as  to  define'  its  extent.  This  branch  vein  has  already 
been  sunk  upon  at  this  spot  to  a  depth  of  25  feet.  Little  or  no  emery  is  present.  A 
mass  of  at  least  10  tons  weight  of  the  massive  variety  of  magnetite  lies  loose  in  the 
wood  (with  which  the  northern  slope  of  the  mountain  is  covered),  600  feet  on  the 
direct  coarse  of  this  vein  and  near  to  an  opening  of  what  seems  to  be  its  direct  con- 
tinuation. The  product  of  the  latter  excavation,  however,  is  not  the  present  massive 
variety  of  ore,  but  this  again  occurs  in  quantity  at  the  opening  quite  at  the  summit 
of  the  South  Mountain,  forming  a  part  of  the  great  emery  vein  which  there  for  a  dis- 
tance of  several  rods  widens  out  to  at  least  15  feet.  It  here  occurs  in  a  series  of 
several  more  or  less  interrupted  seams,  often  affording  masses  6  or  8  inches  thick  and 
quite  pure,  though  in  immediate  proximity  to  the  emery. 

The  massive  magnetite  passes  into  the  thin-veined  where  the  seams  are  half  an 
inch  and  less  in  thickness,  traversing  the  corundophilite  or  chloritoidal  mineral, 
among  whose  particles  are  frequent  chinks  or  cavities  constituting  a  very  fissile 
open  rock.  When  these  seams  or  veins  become  much  broken  or  interrupted  we  have 
what  may  be  called  the  disseminated  variety.  All  three  coexist  in  the  same  vein  and 
often  graduate  insensibly  to  each  other,  the  ore  itself  being  in  each  variety  entirely 
identical. 

The  stony  magnetite  exists  in  other  places,  and  is  disseminated  in  smaller  grains 
through  a  firmer  gangue,  identical  in  character  with  that  constituting  the  stony  emery. 
It  is  well  seen  at  a  place  above  referred  to,  where  a  vein  has  been  worked  upon  600 
feet  to  the  north  of  the  summit  of  the  IsTorth  Mountain,  and  whence  50  tons  of  ore 
have  been  raised  for  the  furnace.  It  here  exists  in  the  proportions  of  50  to  60  per 
cent  throughout  the  vein,  which  is  3  feet  wide.  As  the  vein  is  free  from  emery,  it  may 
prove  to  be  a  prolongation  of  that  bearing  magnetite  at  the  top  of  the  mountain. 

Dr.  Jackson  has  detected  the  presence  of  titanium  in  the  emery  of  Chester,  ren- 
dering it  probable  that  it  will  also  be  found  in  the  accompanying  magnetite.  Should 
this  prove  to  be  the  case,  it  will  only  be  in  mere  traces,  and  will  probably  increase  the 
value  of  the  ore  for  iron  making.  It  is  quite  certain  that  all  the  compounds,  both  of 
sulphur  and  phosphorus,  are  entirely  wanting  throughout  the  formation. 

■f 
3.  Corundum. 

This  species  consists  of  the  well-known  pure  anhydrous  alumina,  and  is  rare 
even  in  mines  of  emery.  It  is  nevertheless  occasionally  found  in  those  of  Turkey, 
occurring  in  the  form  of  thin  seams,  small  grains  (often  of  a  blue  color),  and  rarely  in 
crystals  diffused  through  the  emery  stone.  It  occurs  rarely  also  at  Chester,  but  thus 
far  has  been  met  with  only  in  seams  or  veins  one-half  or  three-quarters  of  an  inch  thick, 
though  exhibiting  a  surface  of  nearly  a  square  foot.  It  is  grayish  white,  highly  crys- 
talline, like  that  from  the  Carnatic.  The  seams  occur  in  the  granular  and  compact 
emery. 


THE  OIIESTKR  EMEUY  BED. 


125 


To  complete  this  general  description  of  the  locality  it  may  not  be  deemed  super- 
fluous to  add  the  interesting  geological  fact  that  in  two  places  the  surface  of  the 
emery  vein  (near  the  summit  of  each  mountain),  for  a  distance  of  several  rods  in  each 
case,  has  been  deeply  grooved  and  smoothed  by  glacial  action.  That  the  friction  pro- 
ducing this  effect  must  have  been  enormous  is  apparent  from  the  size  and  depth  of  the 
channels,  no  less  than  from  the  initial  hardness  of  the  mineral  worn  away;  and  that 
it  could  not  have  been  the  result  of  running  water  is  demonstrated  by  recurring  to 
the  example  of  river  action  in  the  Westfield  River  upon  another  portion  of  the  same 
vein,  where  no  such  smoothing  effect  has  been  produced;  but  in  place  we  have  merely 
an  eroded,  pitted  surface  from  which  the  coarse  crystalline  particles  of  the  hard  emery 
are  left  projecting,  precisely  as  garnet  and  staurotide  are  seen  on  merely  weathered 
faces  of  mica- slate. 

Passing  now  from  the  geological  features  of  the  region  we  enter  upon  a  brief 
notice  of  the  vein  itself  and  its  mineralogical  contents.  The  principal  gangue  or  matrix 
may  be  said  to  be  chloritoidal.  It  can  not  properly  be  called  chlorite  slate  or  even 
chloritic  trap,  inasmuch  as  the  green  chloritoidal  mineral  it  contains  is  considerably 
removed  in  character  from  the  species  chlorite.  This  opinion  is  based  not  so  much 
upon  its  wanting  the  color  and  argillaceous  odor  of  chlorite  as  upon  the  consideration 
that  where  crystallized  it  is  found  to  be  harder  and  heavier  than  that  mineral  and 
further  differs  from  it  by  containing  less  magnesia  and  more  alumina  and  protoxide 
of  iron  than  belong  to  chlorite.  In  fact,  it  is  much  nearer  to  corundophilite,  a  mineral 
thus  named  by  me  from  its  being  the  almost  constant  attendant  of  corundum.  It  is 
not  certain,  however,  that  true  chlorite  is  absolutely  wanting  in  the  vein,  or  at  least  in 
the  contiguous  talcose  slate,  and  inasmuch  as  masonite  and  ottrelite,  varieties  of  the 
species  chloritoid,  are  often  present,  I  shall  generally  speak  of  the  gangue  or  vein  stone 
as  chloritoidal  rock. 

Minerals  in  the  Vein. 

1.  Emeky. 

Not  a  little  confusion  has  hitherto  prevailed  as  to  the  mineralogical  and  chemical 
nature  of  this  substance.  A  common  opinion  has  been  that  it  is  a  mechanical  mixture 
of  corundum  and  magnetite,  while  some  have  imagined  it  to  be  a  triple  compound  of 
alumina  and'  the  two  oxides  of  iron.  Dr.  Jackson,  in  view  of  his  own  analyses  of 
emery,  conceives  it  to  be  a  combination  only  of  alumina  and  the  protoxide  of  iron.' 

He  found — 


Chester. 

Nasos. 

Alumina 

1. 

60.4 
39.5 

2. 
59. 05 
40.95 

62.3 
37.7 

Protoxide  of  iron 

'  See  Am.  Jour.  Sci.,  2d  series,  Vol.  XXXIX,  January,  1865. 


126       GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

and  he  suggested  that  it  be  considered  a  distinct  species  in  place  of  being  included 
as  a  variety  under  corundum.^  His  conclusion  would  obviously  be  acquiesced  in  were 
it  not  for  the  strong  resemblance  in  strife  and  cleavage  between  the  emery  and  common 
corundum,  making  it  impossible  for  us  to  separate  the  sabstances  crystallographically 
from  one  another.  It  would,  however,  be  singular  if  two  minerals  differing  so  widely 
in  their  other  physical  qualities  should  be  specifically  identical. 

Nothing  like  a  perfect  crystal  of  emery  has  yet  been  found  at  the  mine,  but  it  is 
quite  remarkable  that  the  mineral  is  here  generally  coarsely  massive  or  in  large 
separate  individuals,  often  of  the  size  of  kernels  of  Indian  corn  (maize),  whose  cleav- 
age is  perfect,  and  which  present  on  their  planes  the  delicate  strife  so  characteristic 
of  adamantine  spar  from  the  Oarnatic.  The  color,  moreover,  is  perfectly  uniform,  a 
reddish-brown  with  a  faint  coppery  luster.  Its  specific  gravity  is  superior  to  that  of 
corundum  by  nearly  five-tenths,  while  its  power  of  abrading,  as  accurately  determined 
in  the  Turkish  and  Grecian  varieties  by  Dr.  J.  L.  Smith,  is  less  than  half  that  of  the 
sapphire,  though  in  all  its  varieties,  and  especially  that  of  Chester,  its  scratching 
power  or  true  hardness  is  sufiicient  to  scratch  topaz.     It  is  constantly  magnetic. 

In  chemical  composition  the  Chester  emery  is  equally  uniform,  and  in  constitu- 
tion may  be  considered  strictly  isomorphous  with  the  magnetite,  which  species  indeed 
coexist  in  the  same  vein  or  in  closely  contiguous  offshoots  therefrom.  Supposing 
alumina  to  have  replaced  the  peroxide  of  iron  (ferrous  acid),  we  then  have  instead  of 
ferrite  of  iron  (magnetite),  the  aluminate  of  the  same  base  (emery),  the  chemical 
expression  of  the  first  being  FeiF,  that  of  the  second  Fe^. 

The  composition  of  emery  in  100  parts,  being  deduced  from  this  formula,  gives  a 
composition  scarcely  different  from  the  results  of  actual  analysis.  Its  percentage  of 
metallic  iron  is  therefore  a  fraction  over  29.  It  hence  becomes  apparent  how  natural 
was  the  mistake  of  regarding  it  as  an  ore  of  iron. 

Several  varieties  of  emery  at  Chester,  growing  out  of  the  size  of  particles,  their 
mode  of  aggregation,  and  mixture  of  other  minerals  require  to  be  pointed  out. 

(a)  Granular  emery. — This  occurs  in  flattened  grains,  from  the  size  of  kernels  of 
Indian  corn  down  to  that  of  peppercorns,  disseminated  through  corundophilite.  The 
grains  rarely  touch  each  other  and  are  distributed  through  the  rather  open  green 
mineral,  with  their  flat  faces  parallel  to  the  foliation  of  the  gangue.  Hence  this 
variety  cleaves  without  difficulty  into  slaty  fragments  a  few  inches  in  thickness.  It 
also  breaks  crosswise  without  much  difficulty.  The  pure  emery  forms  from  one-half 
to  three-fifths  the  bulk  of  the  aggregate. 

(6)  Veined  emery. — This  variety  arises  from  the  occasional  contact  and  partial 
union  of  the  individuals  (by  their  edges  mostly)  of  the  preceding  variety.  The  veins 
are  much  interrupted  and  are  rarely  above  half  an  inch  thick.  The  granular  and 
veined  varieties  sometimes  pass  into  each  other. 

(c)  Compact  emery. — This  variety,  though  not  absolutely  compact  in  the  mineral- 
ogical  sense,  is  nevertheless  a  very  close,  fine-grained  mineral  in  its  structure,  the 

1  Should  it  hereafter  be  found  proper  to  separate  emery  from  corundum  the  name  of  emeriie  might 
not  be  an  unsuitable  designation  for  the  new  species. — [Shepard.] 


THE  CHESTEE  EMERY  BED.  129 

4.    DiASPOBB. 

This  is  liydrated  alumina,  perhaps  the  most  strictly  characteristic  accompani- 
ment of  emery  in  the  Grecian  Archipelago  and  Turkey.  It  occurs  at  Chester  precisely 
as  in  those  regions,  viz,  in  needle-shaped  crystals  and  bladed  masses,  chiefly  upon 
the  cross  joints  of  the  emery  blocks,  though  sometimes  embedded  (in  compressed  round 
masses)  quite  within  its  substance.  It  is  generally  colorless,  though  sometimes  of  a 
pinkish  or  violet  tint.  Perfect  crystals  of  the  usual  form  are  not  wanting  where  the 
usual  open  spaces  exist  in  the  inasses.  Crystals  also  of  corundophilite  and  very  rarely 
of  brookite  are  found  embedded  in  it. 

5.  Margaritb. 

Scarcely  less  characteristic  of  emery,  and  also  of  corundum,  is  the  present  mineral, 
a  species  whose  general  aspect  suggests  that  of  mica,  from  which  it  difi'ers  in  possess- 
ing a  greater  hardness  and  a  lower  dose  of  silica  with  a  corresponding  increase  of 
alumina  added  to  an  almost  total  absence  of  either  of  the  alkalis.'  The  margarite 
presents  itself  frequently  and  with  a  richness  of  crystallization  and  color  nowhere  else 
known.  It  is  always  in  near  proximity  to  the  purest  masses  of  emery — sometimes 
traversing  it  in  veins,  at  others  coating,  more  or  less  perfectly,  large  and  small  rounded 
masses  of  it  with  layers  an  inch  or  more  in  thickness.  The  laminte  of  the  margarite 
are  arranged  transversely  in  respect  to  the  direction  of  the  seams,  i.  e.,  they  stand  at 
right  angles  to  the  walls  of  the  veins.  Sometimes  an  open  space  exists  in  the  middle 
of  the  margarite  seam,  when  the  mineral  exhibits  very  rarely  regularly  terminated 
crystals  with  which  also  crystals  of  corundophilite  are  associated.  Emery  grains  are 
likewise  to  be  detected  everywhere  among  the  margarite.  Its  color  is  almost  univer- 
sally of  a  pinkish  tint.  In  a  few  instances,  however,  where  it  occurs  in  detached 
scales  mixed  up  with  a  yellowish  epidote  In  the  massive  emery,  it  assumes  a  grayish 
color  and  might  be  mistaken  for  ordinary  mica,  a  species  which  I  have  nowhere 
recognized  in  the  formation. 

6.  Ottrblitb  (Masonitb,  Chloritoid). 

This  species  belongs  to  the  same  mineralogical  group  as  the  preceding,  but 
differs  from  it  in  many  physical  properties  no  less  than  in  chemical  composition.  It 
is  in  disseminated  scales  of  a  blackish-green  color,  whose  breadth  is  rarely  more  than 
a  quarter  of  an  inch.  They  present  considerable  resemblance  to  mica  where  seen  on 
weathered  surfaces  of  the  vein  or  on  open  joints  of  the  rock,  but  are  easily  distin- 
guished by  their  greater  hardness  and  want  of  elasticity.  It  is  chiefly  confined  to  the 
stony  emery.  In  composition  it  differs  considerably  from  the  margarite,  having  above 
20  per  cent  of  protoxide  of  iron,  together  with  6  per  cent  of  water,  and  stands  in  relation 
to  mica  somewhat  as  emery  does  to  corundum. 

1  This  uonalkaline  feature  of  the  contents  of  the  vein,  together  also  with  the  paucity  of  silica, 
seem  to  he  essential  conditions  of  all  the  emery  veins.     It  is  curious  to  remark  how  completely  all 
the  other  micas,  as  well  as  the  feldspars,  with  the  exception  of  the  indianite,  itself  not  abundant,  are 
excluded  from  the  formation. 
MON  XXIX 9 


130  GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

7.   COEUKDOPHILITE. 

The  present  mineral  has  not  yet  been  fully  analyzed.  An  imperfect  examination 
made  of  a  few  grains  of  it  found  along  with  the  sapphire  of  Buncombe,  ISTorth  Carolina, 
lead  to  the  conclusion  that,  like  ottrelite,  it  is  a  silicate  of  alumina  and  protoxide  of 
iron,  but  with  little  lime  and  magnesia.  Des  Cloizeaux  has  described  it  as  one  of  the 
micaceous  minerals,  but  it  rather  appears  to  belong  to  the  clinochlore  group.  Its 
crystallization  is  near  to  mica  and  its  hardness  is  between  2  and  3.  Its  laminae 
are  inelastic  and  almost  brittle.  In  color  and  in  the  arrangement  of  its  particles, 
even  when  giving  rise  to  a  slate,  as  it  often  does,  it  does  not  resemble  the  well-known 
mineral  chlorite.  It  is  of  all  others  the  most  abundant  gangae  mineral  of  the  purer 
varieties  of  both  emery  and  magnetite. 

8.  Indianite. 

Exterior  to  its  vein,  on  its  eastern  side  and  a  few  feet  within  the  talcose  slate, 
at  a  place  on  the  South  Mountain  near  the  smaller  Westfield  Eiver,  runs  a  layer  or 
stratum  from  6  inches  to  2  feet  in  thickness,  called  by  the  workmen  "  the  fringe  rocTcP 
It  consists  of  a  soft,  columnar  mineral,  but  it  is  difQcult  to  say  whether  it  is  chlorite  or 
corundophilite,  or  whether  it  may  not  be  a  mechanical  mixture  of  the  two.  The 
columns  or  fibers,  if  such  they  can  be  called,  are  perpendicular  to  the  sides  of  the 
vein  and  are  made  up  of  superimposed  scales  of  the  mineral.  The  columns  have  been 
rendered  tortuous  and  wavy  by  lateral  pressure.  Through  the  middle  of  this  stratum 
runs,  with  occasional  interruptions,  a  vein  of  indianite  varying  from  2  to  10  inches  in 
thickness.  The  mineral  is  massive,  finely  granular,  of  a  yellowish  color,  and  contains 
grains  of  corundum,  whereby  it  is  easily  capable  of  scratching  quartz. 

9.  Tourmaline. 

This  is  also  a  highly  prevalent  mineral  throughout  the  entire  course  of  the  vein, 
though  perhaps  most  abundant  on  the  l^orth  Mountain.  It  is  more  frequent  near  the 
sides  of  the  vein,  though  at  some  places  it  is  interlaminated  through  its  entire  mass, 
showing  itself  on  the  cleavage  surfaces.  The  crystals  are  often  several  inches  long 
and  from  one-iifth  to  three-fourths  of  an  inch  in  diameter,  being  arranged  in  fascic- 
ular and  radiating  groups  with  their  longer  axes  conforming  to  the  stratification  of 
the  rock.  The  crystals  are  usually  six-sided  prisms  with  smooth  surfaces,  but  always 
lacking  regular  terminations.    Their  color  is  brownish  black. 

10.  Epidote. 

Though  not  abundant,  it  is  nevertheless  frequently  observed,  especially  in  the 
vein  on  both  sides  of  the  smaller  Westfield  River,  near  the  mill.  It  is  in  light 
yellowish-green  crystals,  1  or  2  inches  long  by  one-eighth  to  one-fifth  of  an  inch  in 
diameter,  the  crystals  being  arranged  parallel  to  the  lamination  of  the  vein  and  being 
often  associated  with  grayish  scales  of  margarite,  ottrelite,  and  with  emery.  A  beau- 
tiful radiated  pistachio- green  epidote,  accompanied  by  diaspore,  has  also  been  observed 
in  the  same  vicinity  coating  the  cross  joints  of  the  vein  rock. 


THE  OHESTEE  BMEEY  BED.  131 

11.  Washingtonite  (Ilmenite). 

This  species  is  rarely  met  with  in  black  foliated,  much-curved  laminae  betwixt 
the  double  seams  of  margarite.  On  the  whole,  however,  its  occurrence  is  very  limited 
compared  with  that  in  the  adjoining  mica-slate,  to  which  reference  has  already  been 

made. 

12.  Brookite. 

Only  a  few  crystals  of  this  rare  titanic  acid  have  thus  far  been  noticed,  and 
these  were  found  in  close  connection  with  diaspore. 

13.  Chaxcopyrite  (Yellow  Copper  Ore). 

But  few  grains  of  this  ore  have  been  seen.  It  was  found,  like  the  washingtonite, 
in  margarite,  and  also  upon  the  joints  of  the  gneiss  near  the  emery  vein— in  the 
latter  case  attended  sometimes  by  stains  of  malachite. 

The  foregoing  are  all  the  species  thus  far  found  as  proper  to  the  vein,  with  the 
exception  of  two  apparently  rare  instances — one  in  small  brown  and  copper-colored 
prisms  somewhat  resembling  tyrite,  the  other  in  orange-colored  specks  (slightly 
decomposed)  upon  the  joints  of  the  emery,  and  sometimes  disseminated  through  the 
chlorital  gangue,  both  of  which  await  examination. 

Outside  of  the  vein  with  the  talcose  slate,  besides  the  sparsely  diffused  grains 
of  emery  and  magnetite,  a  greenish- white  laminar  talc  in  thin  seams  occurs  sometimes, 
penetrated  by  a  greenish  yellow  actinolite.  But  the  most  important  mineral  economic- 
ally is  that  modification  of  the  talcose  slate  recognized  under  considerable  variations 
of  character  as  soapstone.  It  is  here  found  in  immense  quantity  at  several  points  on 
the  course  of  the  vein,  but  nowhere,  perhaps,  in  a  more  promising  condition  for  being 
wrought  than  near  the  works  upon  the  South  Mountain.  It  here  quarries  with  much 
facility  in  virtue  of  the  natural  joints  by  which  it  comes  out  in  blocks  of  from  4  to  6 
feet  superficially,  with  a  thickness  of  at  least  1  foot,  often  2  or  more  feet.  It  has  the 
further  recommendation  of  being  free  from  those  foreign  minerals  so  frequently 
interfering  with  its  easy  division  into  slabs  in  the  process  of  sawing. 

It  is  a  point  of  some  importance  to  notice  the  correspondence  between  the 
minerals  enumerated  in  this  paper  and  those  described  by  Prof.  J.  Lawrence  Smith  in 
his  report  ^  as  occurring  at  the  Turkish  and  Grecian  localities  of  emery.  He  concludes 
his  account  of  these  with  the  following  observations  :  "  I  do  not  risk  much  in  saying 
that  the  hydrate  of  alumina  (diaspore),  as  well  as  the  silicates  emerylite  (margarite), 
chloritoid,  and  tourmaline,  and  the  ores  of  iron  (magnetite)  and  titaniferous  iron 
(ilmenite),  wiU  be  found  almost  everywhere  with  the  emery  and  corundum." 

It  will  also  occur  to  the  chemical  geologist  and  mineralogist  that  we  are  now 
furnished  with  an  explanation  of  the  unfrequency  of  the  corundum  and  spinel  families 
of  minerals,  since  their  formation  presupposes  the  existence  of  alumina,  not  only  in 
excess,  but  attended  by  the  absence  of  silica;  while  for  the  formation  of  emery  there 

» See  Am.  Jour.  Sci.,  2d  series,  Vol.  XI,  January,  1851. 


132  GEOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 

is  demanded  the  same  unusual  chemical  conditions,  accompanied  by  the  abundant 
presence  of  protoxide  of  iron. 

The  contrast  between  the  conditions  of  emery  at  the  only  two  regions  of  its 
known  occurrence  grows  out  of  the  difference  in  the  parent  rock  or  originating 
formation.  It  is  saccharoidal  limestone  (white  marble)  in  Asia  and  talcose  slate  in 
America;  for  although  the  emery  vein  at  Chester  is  situated  just  within  the  limits 
of  the  gneiss,  it  can  scarcely  be  doubted,  since  the  emery  and  magnetite  are  both 
found  in  the  slate  and  neither  in  the  gneiss,  that  these  minerals  originated  in  the 
former  at  a  period,  of  course,  when  the  strata  were  horizontal  and  the  talcose  slate 
was  uppermost. 

Conclusion. 

The  preceding  statements  afford  the  fullest  view  I  am  able  to  present  of  the 
emery  mine  at  Chester  as  the  result  of  several  days  of  diligent  examination  of 
the  locality  and  surrounding  region.  The  vein,  though  fully  traced  and  secured  by 
its  present  proprietors  for  the  distance  of  4  miles,  has  not  been  opened  except  at 
comparatively  few  points;  but  the  workings  have  been  sufficiently  extensive  to  demon- 
strate the  perfectly  inexhaustible  supply  of  the  emery,  not  to  say  also  of  the  magnetite 
and  soapstone.  The  vein,  moreover,  following  as  it  does  the  crests  of  two  precipitous 
mountains,  and  holding  a  vertical  position  with  a  width  of  3  to  5  feet  within  well 
defined  walls  throughout,  presents  facilities  for  exploration  that  must  be  obvious  to 
everyone.  Experience  has  not  yet  been  sufficient  to  determine  what  will  be  the  cost 
of  raising  either  the  emery  or  the  magnetite;  but  it  may  be  stated  that  many  hun- 
dred tons  of  both  have  been  mined  at  a  cost  not  exceeding  $2  per  ton,  and  it  is 
confidently  believed  that,  when  the  most  advantageous  localities  for  working  have 
been  decided  upon,  a  reduction  of  this  charge  may  be  effected.  The  fact  that  the  mine 
is  capable  of  being  worked  for  generations  without  incurring  the  smallest  expense  in 
freeing  it  from  water  is  a  consideration  of  much  importance;  while  a  further  advan- 
tage to  the  property  arises  from  the  fact  that  the  smaller  Westfield  Eiver  bisects  the 
vein  midway  of  Its  length  where  the  North  and  South  Mountains  come  together. 
Already  valuable  use  is  made  of  this  water  power  in  extensive  mills  here  erected  for 
crushing  the  emery  and  splitting  the  soapstone,  and  a  further  use  maybe  made  of  the 
same  stream  for  the  erection  of  iron  works  to  any  extent  desired. 

The  Albany  and  Boston  Railroad  passes  within  a  quarter  of  a  mile  of  these 
mills — the  road  from  there  to  the  depot  being  level,  or  at  most  having  only  the  descent 
of  the  stream.  The  distance  (going  east)  to  Springfield,  on  the  Connecticut  Eiver,  is 
30  miles,  and  the  road  to  that  place  is  crossed  at  Westfield,  two-thirds  of  the  way 
thither,  by  a  north-and-south  road,  whereby  the  coast  at  New  Haven  can  be  struck  at 
a  distance  of  62  miles,  thus  affording  by  the  Hudson  Biver  another  connection  with 
New  York  City,  as  well  as  the  entire  region  of  the  West.  Indeed,  it  is  easy  for  any- 
one, with  a  map  of  the  United  States  before  him,  to  assure  himself  that  the  Chester 
mine  is  situated  at  the  very  focus  of  our  system  of  railroad  communication,  as  well  as 
of  the  manufacturing  industry  of  the  country. 


THE  CHESTER  EMEEY  BED.  133 

The  quantity  of  manufactured  emery  at  preseut  annually  consumed  in  the 
TJnited  States  is  over  1,000  tons,  and  the  consumption  is  rapidly  on  the  increase.  This 
supply  has  hitherto  been  derived  in  part  from  London  and  partly  frpm  Alden's 
manufactory  at  Ashland,  near  Framingham,  Massachusetts,  which  establishment  has 
imported  the  crude  stone  direct  from  Smyrna,  though  it  is  now  beginning  to  derive  its 
material  from  Chester. 

The  estimation  in  which  the  American  product  is  held  is  sufficently  vouched  for 
in  the  following  certificates,  coming  as  they  do  from  sources  of  the  highest  respecta- 
bility. The  letters  are  addressed  to  J.  B.  Taft,  esq.,  of  Boston,  who  is  trustee  for  the 
parties  in  interest  to  the  property : 

Office  of  Master  Armorer,  U.  S.  Armory, 

Springfield,  Massachusetts,  November  16,  1S64. 
Dear  Sue  :  The  samples  of  emery  sent  here  for  trial  have  been  tested  and  decided  to  he  auper- 
exeellent.    The  test  has  been  made  without  the  slightest  knowledge  of  its  character  by  either  Mr. 
Chamberlain  or  the  men. 

The  Nos.  46  and  70  are  not  of  the  right  grade,  but  the  evenness  of  all  the  numbers  and  their 
catting  qualities  can  not  be  equaled  by  any  Turkish  or  American  emery. 
Yours,  truly, 

(Signed)  E.  S.  Axlin,  M.  A. 

John  B.  Taft,  Esq. 

Boston,  Massachusetts,  December  1, 1864. 
We  are  very  much  pleased  with  the  emery  you  left  with  us  to  try.  We  find  it  far  superior  to 
anything  we  have  heretofore  used.  We  have  bought  the  best  that  we  could  possibly  find  for  years, 
without  regard  to  price,  and  we  find  by  actual  experiment  that  yours  will  do  one-third  more  work 
than  the  best  London  emery.  We  have  made  a  very  careful  experiment,  and  can  give  a  more  partic- 
ular report  if  necessary.  If  you  can  supply  us  with  the  fine  grades  to  compare  with  the  samples  left, 
you  can  have  all  our  orders  as  soon  as  we  use  what  stock  we  have  on  hand. 
Very  respectfully, 

(Signed)  Hassam  Bkos., 

Makers  of  Fine  Cutlery  and  Surgical  Instruments,  146  Washington  Street,  Boston. 
John  B.  Taft,  Esq. 

Chicopee,  April  20,  1865. 
Dear  Sik  :  The  two  packages  of  emery,  as  samples,  Nos.  46  and  70,  were  received  and  tried — the 
46  on  a  lead  wheel  for  cutting  out  grooves  of  blades  and  the  70  on  a  leather-covered  wheel  for  shaping 
the  large  grooves  of  saber  blades.  Either  test  requires  good  emery  to  do  the  work  successfully.  We 
had  not  the  means  of  making  a  comparative  test,  but  the  best  thing  I  can  say  for  it  is  that  the  work- 
men would  use  no  other  kind  if  they  could  have  emery  like  the  sample.  This  is  of  the  very  best  quality 
we  have  had  an  opportunity  to  use. 

Yours,  very  truly,  (Signed)  Jas.  T.  Ames. 

J.  B.  Taft,  Esq. 

Milling  Shop,  April  25, 1865. 

Sir:  The  following  is  a  report  on  the  relative  qualities  of  American  and  English  emery,  No.  70, 
as  tested  in  this  department.  We  have  given  it  three  different  trials.  The  number  of  wheels  set 
with  emery  at  each  trial  was  12,  6  with  American  and  6  with  English.  The  wheels  used  for  the  first 
trial  were  reversed  for  second  trial,  those  being  set  with  English  emery  in  second  trial  that  were  used 
with  American  in  first  trial,  and  vice  versa. 

You  will  please  notice  the  work  as  performed  by  different  men  with  the  same  emery. 


134 


GEOLOGY  OF  OLD  HAMPSHIEB  COUNTY,  MASS. 
Testa  of  American  and  English  emery. 


"Workmen. 

First  trial. 

Second  trial. 

Third  trial. 

■Wheels. 

Bayonets. 

"Wheels. 

Bayonets. 

Wheels. 

Bayonets. 

Am. 

Eng. 

Am. 

Eng. 

Am. 

Eng. 

Am. 

Eng. 

Am. 

Eng. 

Am. 

Eng. 

2 
2 
2 

2 
2 
2 

38 
45 
24 

18 
24 
25 

2 
2 
2 

2 
2 
2 

23 
31 
33 

25 
52 
42 

2 
2 
2 

2 
2 
2 

35 
32 
68 

36 
47 
55 

Total 

6 

6 

107 

67 

6 

6 

87 

119 

6 

6 

135 

138 

RECAPITULATION. 


Hecapitolation . 


American 
English 


■Whole 

number  of 

"wheels. 


18 
18 


Bayonets 
polished. 


328 
329 


Yours,  respectfully, 


(Signed)  W.  G.  Chamberlain,  Foreman. 


[Indorsement.] 


EespectfuUy  referred  to  Mr.  Taft  for  his  information. 

(Signed)  T.  T.  S.  Laidley,  Major  of  Ordnance. 

U.  S.  Armory,  Springfield  MiLLiista  Shop,  April  27, 1865. 
Sir:  The  folio-wing  is  a  report  on  the  result  of  an  experiment  made  in  this  department  on 
American  and  English  emery.  No.  70 : 


Butt  plates. 

Bayonets. 

No.  of 
wheels. 

Tangs 
of  butt 

plates 
polished. 

No.  of 
wheels. 

Bayonet 

backs 

polished. 

No.  of 
wheels. 

Bayonet 

fronts 

polished. 

4 
4 

256 
211 

5 
5 

223 
225 

5 
5 

253 
250 

A  quantity  of  Nos.  80  and  90  American  emery  is  desirable  for  further  experiments. 
■Very  respectfully, 

(Signed)  W.  G.  Chamberlain,  Foreman. 

[Indorsement.! 

Respectfully  for-warded  to  Mr.  Taft  for  his  information.  Several  -workmen  this  morning  asked 
for  the  American  emery  to  put  on  their  -wheels.  This  is  the  best  indication  of  its  quality.  Please 
send  as  soon  as  possible  some  of  Nos.  80  and  90. 

(Signed)  T.  T.  S.  Laidley,  Major  of  Ordnance. 


TnB  CHESTER  EMEEY  BED.  135 

There  would  appear  to  be  one  quality  iu  the  Chester  emery  particularly  recom- 
mendiug-  it  over  tlie  Asiatic  variety.  It  is  this,  the  foreign  emery  is  liable  to  oxida- 
tion, while  the  American  is  not,  it  remaining  bright  and  clean  after  being  moistened 
and  exposed  to  air.  The  damage  by  oxidation  is  not  only  a  partial  loss  of  hardness, 
but  the  coating  of  the  particles  by  rust  interferes  materially  with  their  adhesion  to 
the  wheel ;  consequently  a  wheel  charged  with  the  American  emery  best  retains  its 
charge  and  accomi)lishes  the  most  abrasion.  That  this  is  a  well-ascertained  difference 
between  the  substances  from  the  two  localities  is  apparent  from  the  invariably  rusted 
appearance  of  the  crude  stone  coming  from  the  East,  whereas  the  produce  of  the 
Chester  mine  and  even  the  loose  stones  lying  about  the  vicinity  betray  not  the 
slightest  tendency  to  oxidation.  I  am  informed  also  by  Mr.  Alden,  the  emery  manu- 
facturer at  Pramingham,  that  he  has  long  been  aware  of  a  2  per  cent  gain  in  weight 
to  his  manufactured  Naxos  emery — an  increase  which  under  the  circumstances  may 
fairly  be  ascribed  to  the  fixation  of  atmospheric  oxygen  in  the  production  of  iron 
rust.  It  is  singular,  indeed,  that  the  same  mineral,  though  from  different  localities, 
should  not  exhibit  the  same  phenomenon  when  subjected  to  similar  conditions;  but 
numerous  examples  of  other  minerals  are  familiar  to  the  mineralogists,  presenting  the 
same  capricious  instability  of  constitution. 

London,  21  Norfolk  street,  Strand,  1865. 

GENERAL  DESCKIPTION. 

The  Westfield  River  (the  Agawam)  runs  east  across  the  strike  until, 
entering  the  northwest  corner  of  Chester,  it  svpings  round  the  north  end 
of  the  broad  hornblende  band  already  described,  forming  the  boundary 
between  this  and  the  Middlefield  serpentine,  and  running  south  through 
the  township  nearly  with  the  strike,  it  occupies  a  somewhat  wider  valley, 
in  which  is  the  village  of  Chester.  This  valley  is  excavated  in  the  softer 
sericite-schists,  and  the  greater  durability  of  the  vertical  hornblende-schists 
(amphibolite)  finds  expression  in  the  sharp  ridge  of  the  North  Mountain — 
or  Gobble  Hill,  as  it  is  called  with  less  euphony  by  the  inhabitants — which, 
seen  from  north  or  south,  rises  like  a  tower  and  is  a  prominent  landmark. 
A  small  brook  coming  in  from  the  west  in  a  deep,  narrow  valley  separates 
it  from  the  South  Moiintain,  which  rises  to  greater  height,  but  is  more 
rounded  and  falls  away  southward  to  the  common  level  of  the  high  ground 
iu  Blandford. 

The  great  height  of  these  hills,  about  750  feet  above  the  village,  1,583 
and  1,797  feet  above  the  sea,  is  due,  as  said  above,  to  the  amphibolite 
band,  and  to  the  south,  where  this  breaks  up  into  several  beds  intercalated 
with  sericite-schist,  the  ground  falls  off. 


136 


GEOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 


Starting  at  the  north  end  of  the  great  amphiboHte  bed  and  at  or  near 
its  junction  with  the  sericite-schist  on  the  east — that  is,  I  suppose,  its  former 
upper  sru-face — ^the  first  exposure  of  the  emery,  and  the  most  interesting  one 
offered  for  study  at  present,  occurs  in  a  ledge  projecting  into  the  Agawam 
River  on  its  left  bank  near  the  most  northerly  railroad  bridge  over  the  river 
in  Chester,  north  of  L.  Otis's  house. 

Fig.  6  represents  this  reef,  which  projects  into  the  river,  where  the 
wear  of  liigh  water  keeps  a  fresh  surface  suitable  for  study. 

The  country  rock  is  an  epidotic 
amphibolite  (a),  contorted  and  thin- 
laminated.  The  tortuous  lines  in  the 
drawing  represent  the  foliation,  and 
along  the  western  side  of  the  principal 
vein,  so  far  as  it  retains  its  greater 
thickness,  the  laminae  bend  around,  often 
quite  sharply,  so  as  to  end  abruptly 
against  the  emery  vein,  the  lamination 
being  at  times  continued  tln-ough  the 
"fringe  rock"  (c).  On  the  west  of 
the  naiTOwed  portion  of  the  vein,  as 
well  as  along  the  whole  eastern  side 
of  the  same,  the  lamination  of  the 
schist  accommodates  itself  quite  accu- 
rately to  the  irregular  boundary  of 
the  vein. 

Around  the  smaller  vein  to  the 
east  the  structure  of  the  schist  is  still 
more  complex,  and  in  part,  especially  in  the  small  mass  which  is  wholly 
inclosed  in  the  vein,  the  lamination  is  entirely  obliterated,  and  filaments 
from  the  vein  are  spun  out  into  the  schist  until  they  become  as  thin  as  a 
knife  blade. 

A  heavy  vein  of  white  quartz  {d)  runs  parallel  to  the  main  vein  in  its 
contracted  portion,  at  a  distance  from  it  of  1  to  2  feet,  and  bunches  out 
several  times  to  a  width  of  a  foot  or  more. 

The  emery  vein  (&)  where  it  comes  out  from  the  bank  is  scarcely  a 
foot  wide  and  is  growing  thinner.      It  expands  northerly,  at  first  quite 


'^'z^ 


Fig.  6. — Map  of  emery  veins  in  epidote-amphibolite  at 
nortit  end  of  bed  on  the  bank  of  the  "Westfield  River,  Chea- 
ter, a,  Epidote-amphibolite ;  b,  magnetite-emery  beds ; 
c,  biotite  fringe  rock;  d,  quartz  veins;  c,  tourmaline. 


THE  CHESTER  EMERY  BED.  137 

suddenly  and  then  more  gradually,  to  12  feet,  and  appears  again  in  the 
river  in  an  isolated  rock  Avith  a  somewhat  greater  width. 

The  customary  "fringe  rock"  (c)  borders  the  vein  on  both  sides  from 
an  inch  to  a  foot  wide,  the  width  being  rudely  proportioned  to  the  width  of 
the  emery  vein..    It  is  a  soft  schist,  made  up  wholly  of  biotite. 

The  emery  vein  is  a  chloritic  magnetite  containing  in  abundance 
bronze-colored  grains  of  emery,  and,  along  the  borders  of  the  thicker  portion 
of  the  main  vein  and  of  the  eastern  vein,  a  considerable  quantity  of  brown- 
black  tourmaline  in  delicate  stellate  forms  (e). 

This  extreme  contortion  of  the  amphibolite  is  rare  in  the  region,  and  I 
may  call  to  mind  that,  following  the  line  of  strike  across  the  river  from  this 
point,  one  comes  directly  upon  the  line  of  junction  of  the  serpentine  (which 
has  replaced  the  amphibolite)  and  the  sericite-schist,  and  that  the  latter  is 
also  contorted  to  an  equally  extreme  degree. 

From  the  outcrop  upon  the  river  bank  one  follows  the  vein  southward 
up  through  a  notch  in  the  mountain,  where,  about  800  feet  south,  it  has  been 
opened  and  some  iron  ore  taken  out,  and  then  up  along  the  eastern  slope 
of  the  mountain,  just  under  the  crest,  to  the  new  mine,  about  a  mile  north 
of  the  village,  where  alone  work  was  in  progress  in  1883. 

The  part  of  the  vein  rich  in  emery  was  about  1  to  3  feet  wide  where  I 
saw  it,  and  the  corundum  was  regularly  disseminated  porphyritically  in 
rich  bronze-colored  crystals  5-15"""  across,  affording  a  very  rich  ore.  The 
soft,  green  chloritic  "fringe  rock"  was  developed  in  great  force  and  cuts 
the  emery  bed  in  the  bottom  of  the  opening  as  a  heavy  horizontal 
cross- vein.  It  was  filled  with  bright  fresh  cubes  of  pyrite  and  crystals  of 
tourmaline  10-30'"°'  long  and  2-3""'"  in  diameter,  which  were  all  regular 
hexagonal  prisms,  with  rather  dull  unstriated  sides.  They  are  often  radiated 
and  fasciculate. 

With  a  lens  sHdes  of  the  rock  show  wavy  bands  of  a  pale-salmon  color, 
which  alternate  with  bands  and  lenticular  patches  of  bright  green.  The 
former  are  very  fine  fibrous,  and  show  the  aggregate  polarization  of  talc. 
The  latter  is  in  coarser  scales,  often  radiate,  and  they  polarize  from  green  to 
black.  They  have  low  absorption  and  pleochroism:  x;  =  pale  blue-green; 
Xi  =  same;   a  =  bright  yellow;   extinction  inclined  8°  from  the  cleavage. 

Magnetite  is  abundant;  also  deep-brown  grains  of  chromite,  the  former 
often  interlaminated  with  chlorite.     The  tourmaline  is  in  sharp  hexagons; 


138       GEOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS, 

G?  =  black,  £  =  deep  prussian-blue,  with  black  border.  Sharply  refringent 
grains  of  titanite,  with  dark  border  surrounding  them,  occur  in  the  chlorite. 
The  opening  was  otherwise  poor  in  the  usual  accessory  minerals  of  the  vein, 
only  traces  of  margarite  occurring.  Here  also  a  branch  vein  nins  off  to 
the  east  and  the  mica-schist  is  greatly  contorted. 

Going  south  toward  the  old  mine  in  the  valley,  one  passes,  about  a 
third  of  the  way  on,  the  large  abandoned  Sackett  mine,  opened  about  50 
feet  on  the  vein,  which  is  here  about  12  feet  wide  and  has  been  extensively 
woi'ked  for  magnetite.  The  thin  "fringe  rock"  can  be  seen  attached  to  the 
hornblende-schist  on  the  west  wall  of  the  opening  over  a  broad  surface. 
In  the  magnetite  only  a  limited  amount  of  emery  is  visible,  and  no  other 
minerals  could  be  found.     Dr.  Jackson  says: 

On  tlie  North  Mountain  the  emery  is  more  largely  crystalline  and  less  mixed  with 
magnetic  iron;  it  is  more  like  corundum,  but  still  contains  the  combined  protoxyd  of 
iron,  characteristic  of  true  emery. 

Three  large  beds  of  rich  magnetic  iron  ore,  distinct  from  the  ore  accompanying 
the  emery,  occur,  the  ore  yielding  54^  per  cent  of  metallic  iron.  This  ore  is  mined 
and  is  smelted  into  bar  iron  by  forge  fires,  and  is  also  sold  to  mix  with  the  hematites 
and  carbonates  of  iron  at  the  Lenox  and  Stockbridge  furnaces. 

The  next  opening  on  the  vein  is  at  the  foot  of  North  Mountain,  north 
of  the  Becket  road  and  directly  opposite  to  the  main  works.  (See  fig.  7, 
p.  141.)  Here,  at  the  head  of  a  small  ravine,  an  adit  was  driven  in  500 
feet  during  1893,  and  brought  out  a  great  quantity  of  the  fringe  rock,  filled 
with  beautiful  rosettes  of  the  hexagonal  tourmaline.  Of  the  further  con- 
tinuation of  the  vein  across  the  brook  and  up  the  north  face  of  South 
Mountain  Dr.  Jackson  writes  as  follows: 

The  principal  bed  of  emery  is  seen  at  the  immediate  base  of  the  South  Mountain, 
where  it  is  4  feet  wide  and  cuts  through  the  mountain  near  its  summit  at  an  angle  of 
70°  inclination,  or  dip,  to  the  eastward.  Its  course  is  N.  20°  E.,  S,  20°  W.,  and  its 
known  extent  4  miles.  Near  the  summit  of  the  mountain  the  bed  expands  to  more 
than  10  feet  in  width,  and  in  some  places  is  even  17  feet  wide. 

The  alternations  of  rock  in  two  sections  are  as  follows,  beginning  to  the  eastward 
[that  is,  at  the  top  J : 

1.  a,  Mica-slate;  6, 15  feet  soapstone  or  talcose  rock;  c,  2  feet  crystallized  talc; 
^,talcose  slate;  e,  1  foot  granular  quartz ;/,  chlorite  slate;  j/,  4  feet  emery;  h,  chloritoid 
and  margarite ;  t,  magnetic  iron  ore ;  j,  hornblende  rock  highly  crystalline. 

2.  a,  Mica-slate;  &,  6  feet  magnetic  iron  ore;  c,  talcose  slate;  <?,  6 J  feet  magnetic 
iron  ore;  e,  chloric  slate;  /,  hornblende  rock,  crystallized;  <;,  7  feet  emery,  chloritoid, 
and  margarite;  li,  magnetic  iron  ore;  i,  hornblpiide  rock. 


THE  CHESTER  EMERY  BED.  139 

Tho  elevation  of  the  upper  outcrop  of  this  bed  above  the  immediate  base  of  the 
mountain  is  750  feet.  There  are  remarliable  rounded  masses  of  pure  emery  3  feet  in 
diameter  in  this  bed  entirely  invested  with  a  coat  of  rose-colored  margarite  and  a 
thick  layer  of  bright  green  chloritoid,  the  investing  coat  being  from  half  an  inch  to  2 
inches  in  thickness.  It  is  found  extremely  difficult  to  break  up  these  masses  of  solid 
emery,  drilling  holes  in  them  being  very  slow  and  laborious,  and  no  grip  can  be  had 
on  their  rounded  sides  by  the  sledge.  A  heavy  drop  hammer  will  be  required  to  break 
them  to  pieces,  or  they  may  be  cracked  by  fire  if  heat  does  not  injure  the  emery. 

The  first  of  the  two  sections  given  by  Dr.  Jackson  and  quoted  above 
refers  to  the  old  mine  on  the  brook  between  the  two  mountains. 

The  talc  on  the  east  has  a  thickness  of  from  5  to  15  feet.  Much  of 
it  is  verj  pure,  lightish-green,  schistose  talc.  Much  of  it  also  carries  dis- 
seminated dolomite,  often  removed  and  leaving  rusty  holes.  In  places  it  is 
a  dark  leek-green,  compact  talc. 

Scattered  through  the  talc  are  remnants,  up  to  a  foot  in  diameter,  of 
the  serpentine  from  which  the  talc  has  doubtless  been  derived.     These 
nodules  are  rounded  and  pass  outwardly  by  gradual  transition  into  the  talc, 
and  veins  of  the  latter  mineral  also  penetrate  the  serpentine.    Large  masses  of 
foliated  talc  could  be  obtained  pure,  but  of  inferior  color — ^a  very  pale  green. 

The  next  band  upon  Dr.  Jackson's  section,  "chlorite  slate,"  is  the  usual 
chloritic  or  corundophilitic  "fringe  rock,"  which  is  here  specially  well 
developed  upon  the  eastern  side  (where  it  contains  the  oligoclase  bed  next 
described)  as  well  as  upon  the  western. 

The  corundophilite,  in  plates  often  20™™  broad,  is  placed  with  consid- 
erable regularity  at  right  angles  to  its  planes  of  contact  with  the  oligoclase 
in  layers  which  reach  40™™  thickness  on  each  side  of  the  latter.  It  often  pen- 
etrates the  emery  vein  in  sheets,  filling  fissures,  and  thus  often  inclosing  on 
all  sides  blocks  of  the  ore,  and  in  cracks  not  wholly  filled  develops  excellent 
crystals,  upon  which  rest  margarite  in  the  finest  foliated  sheets  and  diaspore 
in  thick  masses  of  interlaced  blades  and  in  separate  crystals  of  great  per- 
fection associated  with  fine  needles  of  rutile.  The  corundophilite  is  further 
disseminated  more  or  less  through  the  mass  of  the  magnetite-emery  aggre- 
gate, and  where  this  aggregate  lessens  in  quantity  its  place  is  taken  by  a 
white  to  pink  colored  granular  margarite,  forming  a  schistose  rock,  for  which 
Professor  Shepard  proposes  the  name  corundophilite-schist.^ 

Where  the  corundophilite  wholly  disappears  there  results  an  interesting 

lAm.  Jour.  Sci.,  2d  series,  Vol.  XL VI,  1868,  p.  257. 


140 


GEOLOGY  OP  OLD  HAMPSHIRE  COUNTY,  MASS. 


stratum  of  white  to  reddish,  fiue-grained,  saccharoidal  oiigoclase,  which  was 
very  pure  and  very  persistent,  although  nowhere  reaching  great  thickness. 
Prof.  C.  U.  Shepard  first  called  this  mineral  a  "rose-colored  amphodelite 
associated  with  the  diaspore,"  ^  and  later  described  the  bed  in  question : 

A  vein  of  indianite  many  inches  thick  is  found  near  the  tunnel  on  the  South 
Mountain,  running  for  many  rods  through  the  chlorltic  rock  on  the  east  side  of  the 
emery  vein  (exterior  to  the  gneissoid  wall).  Small  particles  of  crystalline  corundum 
are  diffused  through  the  indianite.^ 

In  his  report  he  adds  only  that  it  is  2  to  10  inches  thick,  massive,  fine- 
granular,  yellowish.^ 

In  a  second  report  Dr.  C.  T.  Jackson  writes: 

The  ijortion  of  the  rock  originally  mistaken  by  me  for  granular  quartzite,  and 
called  indianite  by  Shepard,  proves  on  analysis  to  be  andesine,  although  it  is  harder 
than  stated  in  the  books,  scratching  quartz  crystal  readily.  It  is  very  compact,  flne- 
granular  in  texture,  and  has  G=2.586,  H=7.5,  the  color  slightly  greenish  white.  I 
obtained  for  its  composition : 


1. 

2. 

SiOj 

62.00 
24.40 
3.50 
0.70 
8.07 
1.00 

60.00 
25.00 

AI2O3 

CaO --   .             .   . 

MgO             

NaO 

H,0 

99.67 

85.00 

In  No.  2  there  was  a  trace  of  oxide  of  iron  not  weighable. 

This  fringed  feldspar  bed  can  not  now  be  observed  at  the  mine,  nor  can 
specimens  of  it  be  obtained  there.  Fortunately  a  large  mass,  representing 
the  whole  thickness  of  the  bed,  with  the  green  fringe  rock  attached  on  both 
sides,  is  preserved  in  the  geological  collection  at  Amherst.  It  is  a  gift  of 
Mr.  J.  T.  Ames.  The  feldspar  is  12  inches  wide  and  the  green  fringe  rock 
3  and  4  inches  wide  on  the  two  sides,  respectively. 

'Am.  Jour.  Soi.,  2d  series,  Vol.  XL,  I860,  p.  112. 

nbid.,  p.  123. 

3  Report  Chester  Emery  Mine,  1868,  p.  11. 


THE  CHESTER  EMERY  BED. 


141 


A  study  of  thin  slides  of  the  rock  is  given  in  Bulletin  126  of  the 
United  States  Geological  Survey,  under  "  Oligoclase." 

The  width  of  the  emery  bed  is  given  as  4  feet  by  Dr.  Jackson  in  his 

first  article  quoted  above;  in  his  second^  he  writes: 

The  emery  veiu  enlarges  as  it  goes  in,  and  from  4  feet  has  already  widened  to  7 
feet  S  inches  of  solid  emery  of  the  best  quality.    The  adit  is  now  extended  260  feet. 

In  a  limited  portion  of  the  working  in  the  lowest  shaft  (see  fig.  7, 
below)  the  rock  carries  diaspore  in  large  quantity  and  of  the  finest  color, 
especially  the  isolated  crystals  resting  in  open  fissures  upon  and  partly 


0  lOO 


Fig.  7. — Section  of  old  emery  mine,  Chester.    Section  of  the  main  mine  south  of  the  road  and  plan  of  the  new  mine  north 
of  the  road.    All  drifts  are  in  amphibolite  except  where  emery  is  indicated. 

inclosed  in  crystals  of  corundophilite  and  shot  through  and  overgrown  with 
delicate  needles  of  rutile;  and  radiated  crystals  of  epidote  and  rarely  of 
brookite^  were  of  exceptional  beauty,  both  of  form  and  color.  The  diaspore 
presented  square  prisms  25-30""°'  in  length,  finely  terminated,  of  rich  violet- 
tinted  hair-brown  color.  It  occurs  also  in  compressed,  rounded  masses  quite 
within  the  substance  of  the  emery.' 

I  am  indebted  to  Mr.  Judson  Thomas,  superintendent  of  the  emery 

1  Am.  Jour.  Sci.,  2d  series,  Vol.  XLII,  1866,  p.  107. 

2  Sliepard's  Report  Emery  Mine,  1865,  p.  12. 
nud,  1865. 


142       GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

mine,  for  a  section  of  the  underground  work  at  the  old  mine  south  of  the 
mill,  and  a  plan  of  the  new  opening  directly  opposite  and  north  of  the  brook. 
(See  fig.  7.)  It  will  be  seen  that  the  magnetite-emery  vein  is  not  contin- 
uous, but  lies  in  separate  lenticular  masses  or  chimneys — "pots,"  as  they 
are  locally  called. 

Southerly  the  outcrop  of  the  emery  bed  rises  rapidly  to  the  top  of 
South  Mountain  and  has  been  opened  at  several  points.  About  650  feet 
south  of  the  point  where  the  road  to  the  Melvin  mine  crosses  the  bed  an 
opening  shows  chloritic  magnetite,  without  visible  emery  and  talc,  with 
brown  spar  on  the  east,  proving  that  the  talcose  stratum  is  very  persistent. 

At  the  Melvin  mine,  the  most  southerly  point  to  which  the  bed  has  been 
traced,  the  ore  has  been  removed  in  an  open  working  about  130  feet  on  the 
strike  and  35  to  40  feet  in  depth,  to  the  full  width  of  the  bed,  which  is  6J 
feet  wide  at  the  north  end  and  opens  out  for  a  distance  of  33  feet  to  a  width 
of  16  feet,  and  then  contracts  again  southward  to  a  width  of  nearly  10  feet. 

The  ore  is  mostly  a  chloritic  magnetite  with  few  accessory  minerals, 
margarite  of  rare  beauty  being  the  only  interesting  occurrence.  A  little 
tourmaline  is  present.  The  epidotic  amphibolite  appears  in  a  thin  band  on 
the  east  of  the  emery  bed,  separating  it  from  the  sericite-schist  farther  east, 
and  on  the  west  the  same  amphibolite  adjoins  the  bed  and  makes  up  the 
whole  western  half  of  the  mountain. 

The  soft  chloritic  "fringe  rock"  bounds  the  ore  for  a  distance  and  then 
runs  behind  a  layer  of  hornblende  2^  inches  thick.  Farther  south,  at  the 
Bai'tholomew  soapstone  quarry  in  the  north  of  Blandford,  and  at  the 
Osborn  soapstone  quarry,  the  same  chloritic  "fringe  rock"  occurs,  and  at 
the  latter  place,  adjoining  the  main  soapstone  bed  on  the  west,  a  layer  of 
magnetite  about  1  inch  thick  occurs,  which  I  thought  at  one  time  to  contain 
emery,  but  I  was  not  able  to  confirm  this  on  further  investigation. 

Taking,  however,  the  known  limits  of  the  bed,  there  is  "in  sight"  a 
very  great  quantity  of  magnetite  and  emery — extending  a  length  of  about 
4  miles  and  a  depth  of  about  750  feet  above  the  water  level  of  the  brook, 
and  having  an  estimated  average  thickness  of  4  feet.  Nevertheless,  it  must 
be  admitted  that  the  exploitation  of  the  deposit  has  been  of  much  more 
scientific  than  pecuniary  profit,  and  that  it  has  not  realized  the  sanguine 
expectations  of  the  early  promoters. 


THE  CHESTER  EMEEY  BED.  143 

ASSOCIATION  AND  PARAGENESIS   OF   THE  MINERALS  OF  THE  EMERY  VEIN. 

The  magnetite,  which,  when  pure,  is  very  fine-grained,  compact- 
massive,  with  pecuUar  purple  tint,  becomes  mixed  with  emery  in  gradually 
increasing  proportions — the  "emery-magnetite"  of  Professor  Shepard's 
classification.  The  emery  increases  until  a  harsh,  rough-surfaced  mass  is 
formed,  in  which  the  coppery-brown  corundum  crystals  are  abundantly 
disseminated,  like  the  feldspar  in  a  porphyry.  There  is  also  a  passage, 
by  the  gradtial  increase  of  the  corundophilite  from  the  magnetite,  into  the 
"corundophilite-schist"  of  Professor  Shepard.  The  thin  sections  of  the 
latter  rock  show,  however,  no  corundum,  but  abundant  octahedra  of  mag- 
netite, and  I  have  been  unable  to  convince  myself  of  the  existence  of 
anything  coi'responding  to  the  "stony  emery"  of  Professor  Shepard.  Also 
thin  sections  of  the  "fringe  rock"  show  only  magnetite.  The  pure  mag- 
netite is  at  times  beautifully  jointed.  In  one  piece  three  systems  of  joints, 
about  20°™  apart,  break  up  the  mass  into  rhombohedra  with  about  the 
angles  of  calcite,  and  the  parts  are  slightly  slipped  on  each  other  and 
recemented.  Further,  quite  large  irregular  cavities  in  the  chloritic  mag- 
netite have  fine  blades  of  the  corundophilite  prolonged  freely  into  them 
from  the  mass  of  the  rock. 

In  another  mass  the  "compact  emery"  is  brecciated;  angular  pieces 
about  30-50°""  across  are  separated  20-30'°°'  from  each  other  and  the 
interspace  is  filled  with  fine,  scaly  corundophilite.  In  other  cases,  as  men- 
tioned by  Dr.  Jackson,  large  rounded  masses  of  the  tough  emery  are 
wrapped  around  on  all  sides  by  a  schistose  aggregate  of  corundophilite 
and  margarite. 

Again,  as  mentioned  above,  a  great  cross  vein  of  the  compact  chlorite 
rock,  carrying  much  tourmaline  and  pyrite,  cuts  directly  across  the  vein  at 
the  north  mine. 

In  one  piece  the  light-pink  and  green  schist  is  firmly  joined  to  a  mass 
of  magnetite,  with  its  laminae  at  right  angles  to  the  plane  of  junction. 

In  many  cavities  and  open  cross-joint  fissures  the  surface  is  covered 
by  a  thick  layer — separated  from  the  subjacent  rock  by  a  distinct  suture, 
and  plainly  of  later  formation  under  circumstances  different  from  those 
described  above — of  large,  stoat,  six-sided  crystals  of  corundopliilite,  all 
placed  with  their  vertical  axes  parallel  to  the  surface,  but  taking  any 
direction  in  this  plane,  and  terminated  above  by  black  striated  faces  of  the 


144  GEOLOGY  OF  OLD  HAMPSHIRE  COtTNTY,  MASS. 

prismatic  zone.  Delicate  needles  of  bright-red  rutile  penetrate  this  crust 
or  rest  upon  it.  Broad,  warped  sheets  of  menaccanite  also  are  implanted  in 
or  planted  upon  the  corundophilite,  while  epidote,  margarite,  and  diaspore, 
though  generally  somewhat  intermingled  with  the  chloritic  basal  layer, 
find  their  principal  development  later.  The  epidote,  which  is  rare,  fills 
cavities  with  an  open  network  of  yellowish-green  needles.  The  diaspore, 
in  the  limited  portion  of  the  vein  in  which  it  was  found,  sometimes  filled 
fissures  50-60™™  across  with  a  mass  of  pink  blades  irregularly  arranged. 

The  margarite,  while  it  sometimes  rests  on  and  in  the  chloritic  layer, 
with  its  base  parallel  to  the  surface,  more  commonly  arranges  itself  in  com- 
pact masses  of  broad  plates  at  right  angles  to  the  surface  of  the  joint  plane, 
and  rests  on  the  chlorite,  and  two  such  sheets  often  meet  in  the  center  of  the 
fissure  with  a  central  suture,  and  this  fills  the  whole  cavity.  The  "fringe 
rock,"  generally  a  compact  corundophilite  with  abundant  radiating  hexagonal 
prisms  of  brown-black  tourmaline,  belongs  to  this  second  stage. 

Calcite  is  sometimes  found  between  the  diaspore  and  the  corundoph- 
ilite, though  its  most  abundant  development  occurs  later,  and  menaccanite 
occurs  also  in  the  central  suture,  between  the  seams  of  margarite,  in  much 
curved  laminae.  Chalcopyrite  is  noted  by  Professor  Shepard  in  margarite, 
and  brookite  embedded  in  diaspore.  Parallel  with  this  second  stage  in  its 
earlier  portion,  or  perhaps  even  earlier,  may  be  placed  the  rare  secondary 
veins  of  grayish-white  corundum,  which  reach  a  thickness  in  the  magnetite 
of  15-20°™  and  show  single  cleavage  faces  across  the  whole  width  of  the 
vein.  I  have  not  found  these  so  associated  with  other  minerals  as  to  exactly 
fix  then  age.  Other  veins  in  the  compact  magnetite,  5-10™™  wide,  appear 
at  first  sight  to  be  almost  entirely  calcite,  but  on  dissolving  this  away  the 
following  paragenesis  appears: 

(1)  Corundophilite  resting  on  the  magnetite,  1-4™™  wide,  in  tapering 
hexagonal  crystals,  mingled  with  (2)  rutile  in  its  upper  portion.  The  rutile 
in  long,  hair-brown,  shining,  striated  needles,  often  bent  and  twisted,  often 
sagenite-like,  in  groups  of  deeply  grooved  needles.  This  is  followed  by  (3) 
a  layer  of  corundum,  partly  colorless,  partly  a  most  beautiful  sapphire-blue 
or  pale  pink,  crystallized  in  flat  plates,  which  are  very  acute  rhombohedra, 
with  one  pair  of  faces  developed  greatly  in  excess  of  the  others,  as  is 
indicated  by  the  fact  that,  laid  on  the  broadest  face,  the  ring  system  appears, 
with   convergent  polarized  light,  very  eccentrically  placed.      This  layer 


THE  CHESTER  EMERY  BED.  145 

reaches  a  thickness  of  12""".  Tliis  is  at  times  foUowed  bj-  (4)  disapore, 
which  crystallizes  around  the  blades  of  corundum. 

In  some  veins  the  whole  series  is  closed  (5)  by  an  abundant  develop- 
ment of  raargarite;  in  others  by  a  layer  of  calcite  (G),  up  into  which  the 
thin,  knife-like  blades  of  the  corundum  project,  graphic-granite-like,  and 
on  etching  away  the  calcite  delicate  parallel  threads  of  the  corundum 
appear,  Avith  blades  of  corundophilite  attached  to  them  or  floating  freely 
in  the  calcite,  as  well  as  a  beautiful  lacework  of  rutile  needles  crossing  at 
60°  and  120°.  It  is  in  these  veins  that  the  corundophilite  changes  into 
the  pale-green  amesite  of  Shepard. 

Another  vein,  15""  across,  shows  the  following  interesting  paragenesis 
begimiing  with  the  walls  of  corundophilite-schist  on  either  side: 

Millimeters. 

{a)  A  thin,  silvery  layer  of  margarodite  in  transverse  plates 0. 5 

(6)  Compact  epidote 5. 0 

(c)  Bright  flesh-colored  plagioclase  (oligoclase) 2. 0 

{d)  Mixture  of  last  with  fibrous  crystalline  epidote 7. 0 

(e)  Transparent  square  plates  of  diaspore  in  pockets  along  the 

central  suture 3.  0 

A  third  generation  of  minerals,  jDlainly  of  much  later  origin,  closes 
the  series.  This  consists  of  layers  of  specular  iron  (/)  in  small  rosettes  of 
bright  scales,  upon  which  aragonite  (^)  occurs  in  rosettes  of  long,  thick 
blades,  35-40""  across,  in  small  tufts,  and  in  thick,  granular,  sugary,  white 
crusts,  with  some  pyrite  and  chalcopyrite,  and  finally  the  whole  is  often 
covered  with  a  layer  (li)  of  small  wine-colored  rhombohedra  of  calcite,  |  Tl, 
and  films  of  malachite. 

It  seems  to  me  most  probable  that  the  emery-magnetite  vein  was 
originally  a  deposit  of  limonite  which  was  formed  by  the  replacement  of 
limestone,  and  into  which,  as  in  the  Berkshire  County  limonites,  alumina 
was  carried  by  infiltrating  solutions  and  deposited  as  allophane  and  gibbsite. 
The  subsequent  metamorphism  of  the  bed,  although  it  may  well  have  been 
intimately  connected  with  the  extremely  violent  mechanical  forces  to  which 
the  strata  have  been  subjected,  was  largely  completed  before  these  forces 
had  ceased  their  activity,  as  is  shown  by  the  jointing  and  brecciation  of 
the  magnetite  and  emery,  and  by  this  metamorphism  were  formed  magnetite 
and  corundum,  and,  so  far  as  silica  sufficed,  the  very  basic  corundophilite 
(SiOg  24,  AI2O3  25.9,  FeO  14.8,  MgO  22.7,  H2O  11.9).     The  heavy  stratum 

MON  XXIX 10 


146       GEOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 

of  magnesian  rocks  which  covers  the  emery  bed  seems  to  have  been  the 
source  of  the  magnesia  in  this  mineral.  The  less  altered  ferruginous 
limestone  below  was  changed  into  the  epidotic  amphibolite. 

While  thus  magnetite,  emery,  and  corundophilite  form  the  first  genera- 
tion of  minerals  of  the  bed,  the  latter  mineral  continued  to  be  formed  or 
reformed  in  the  abundant  fissures  produced  by  the  continued  intestinal 
movements  of  the  mass,  cementing  the  breccias  and  forming  thick  cross- 
veins  with  a  fine-grained  chloritic  mass,  at  times  closely  resembling  an 
aphanitic  hornblende  rock,  and  in  this  form  abundantly  associated  with 
tourmalines  (always  in  regular  six-sided  prisms),  with  epidote  and  pyrite. 
In  a  third  and  more  quiet  stadium  the  corundophilite  formed  incrusting 
layers  upon  the  free  surfaces  of  fissures,  made  up  often  of  congeries  of 
broad,  vertical  plates  terminated  above  in  Avell-defined  faces,  and  associated 
with  rutile,  brookite,  menaccanite,  calcite,  diaspore,  margarite,  and  epidote. 

This  stadium  is  closely  parallel  to  the  customary  secondary  fissure 
deposits  of  the  associated  rocks,  especially  the  hornblende-schists,  which 
consist  usually  of  prochlorite,  menaccanite,  rutile,  calcite,  and  epidote,  and 
is  peculiar  only  in  the  substitution  of  corundophilite  for  the  ordinary 
chlorite  and   in  the  presence   of  the   satellites    of   emery,   diaspore,   and 


margarite. 


The  fourth  and  final  stadium  in  the  development  of  the  minerals  of 
the  vein  seems  to  be  quite  distinct  from  and  later  than  the  preceding  and 
to  indicate  the  presence  of  steam  or  heated  and  gradually  cooling  waters  in  a 
new  set  of  fissures  which  cut  across  the  older  diaspore-margarite  veins,  and 
thus  prove  the  later  appearance  of  the  new  series  of  minerals.  The  suc- 
cession— specular  iron,  aragonite,  calcite — clearly  indicates  at  first  steam  or 
hot  water  for  the  formation  of  the  first  and  second,  and  a  transition  to  cooler 
water  for  the  formation  of  the  last.  The  sudden  appearance  of  the  calcic 
carbonate  in  considerable  abundance  is  also  interesting.  Calcium  is  wholly 
wanting  in  the  first  and  second  stadia  defined  above.  A  trace  of  calcite 
and  epidote  in  small  amount,  together  with  margarite,  represents  altogether 
but  a  small  quantity  of  this  element  in  the  third  stadium,  while  here  the 
carbonate  makes  up  the  greater  portion  of  the  new  series  and  may  have 
been  introduced  from  without,  possibly  set  free  l^y  decomposition  of  the 
hornblende  in  its  change  into  serpentine. 


THE  CHESTER  AMPHIBOLITE  AND  SERPENTINES.  147 

KKSUMI^:   OK   I'AKAGENESIS. 

1.  Limoiiite,  gibbsite,  allophane. 

2.  Magnetite,  emery,  disseminated  corundophilite. 

3.  Corundophilite  in  veins,  tom-maline,  pyrite,  epidote,  corundum  in 
veins,  oligoclase. 

4.  Corundophilite  in  iucrusting  layers,  diaspore,  margarite,  rutile, 
epidote,  chalcopyrite,  menaccanite. 

5.  Diaspore,  margarite,  menaccanite,  brookite,  calcite. 

6.  Specular  iron,  aragonite,  calcite,  malachite. 

GENERAL  EXPLANATION  AND  CORRELATION  OF  THE  CHESTER  AMPHIBOLITE 

SERIES. 

I  desire  to  bring  together  here  the  reasons  which  lead  me  to  conclude 
that  this  series  was  originally  a  more  or  less  impure  ferniginous  dolomitic 
limestone,  and  to  consider  also  the  residual  facts  which  favor  the  opinion 
that  these  rocks  were  derived  from  basic  and  ultrabasic  eruptives. 

I  have  attempted  to  trace  the  enstatite-serpentine  and  the  limestone  beds 
of  the  southern  part  of  the  range  back  from  their  present  to  their  earliest 
clearly  demonstrable  condition,  in  a  series  of  sections  following,  which 
have  special  application  to  the  newly  opened  and  most  interesting  quarry 
of  the  Westfield  Marble  Company  (see  page  92),  but  which  are  equally 
true  of  all  the  range  north  to  Blandford. 

ORIGINAL   CONDITION   OF    THE   ENSTATITE-SERPENTINE   AND   LIMESTONE   COMPLEX. 

1.  The  steatitisation. — The  alteration  of  the  abundant  tremolite  beds, 
or  those  of  actinolite  which  do  not  contain  a  large  per  cent  of  iron,  to  talc 
is  common  and  easily  understood.  This  is  the  latest  change  of  the  beds 
concerned,  except  simple  solution  of  the  limestones  and  the  coating  of 
fissures  with  iron  rust. 

The  fibrous-radiate  structure  of  nearly  all  the  steatite  beds  may  be 
assumed  to  be  proof  that  they  are  altered  tremolite  and  actinolite  beds. 

There  has  often  been  an  intermediate  serpentine  stage,  and  serpentine 
of  all  kinds  has  changed  into  talc.  This  is  sometimes  a  very  modern 
change.  I  have  observed  cases  where  it  was  in  considerable  part  post- 
Glacial. 

2.  The  serpentinization. — The  alteration  of  the  magnesian  mineral 
enstatite,  as  well  as  of  the  olivine,  pyroxene,  dolomite,  and  actinolite,  into 


& 


148       GEOLOGY  OF  OLD  HAMPSHIEB  COUNTY,  MASS. 

serpentine  is  also  a  process  not  requiring  special  consideration  at  this  place, 
as  it  has  been  demonstrated  in  a  preceding  chapter  that  the  serpentine  still 
contains  traces  of  unchanged  enstatite,  or  of  the  other  original  mineral  in 
the  case  of  the  corresponding  serpentine.  The  bastite  formation  in  the 
black  rock  is  a  part  of  the  same  process. 

3.  The  tremolitisation. — The  alterations  by  hydration  mentioned  above 
were  subsequent  to  the  change  of  the  limestone  at  the  Westfield  quarry, 
for  several  feet  inward  on  its  eastern  margin,  into  a  quite  pure,  matted  and 
radiated  tremolite,  and  subsequent  to  the  partial  change  of  the  whole  thick- 
ness of  the  limestone  bed  into  the  same  tremolite,  which  is  later  than  the 
formation  of  the  enstatite,  since  its  needles  end  against  the  enstatite  crystals. 

The  band  of  actinolite  which  cuts  across  the  main  quarry,  and  the 
broad  actinolite  selvage  on  the  west  wall  farther  south,  in  the  same  way  cut 
across  both  limestone  and  enstatite,  and  are  plainly  of  later  formation, 
nearly  contemporaneous  with  the  tremolite,  and  formed,  like  it,  by  the 
action  of  heated  siliceous  solutions,  here  ferruginous  and  there  not,  which 
have  been  infiltrated  from  the  schistose  walls.  The  same  alteration  appears 
at  many  places  farther  north  in  the  limestone.  On  the  Alderman  place  in 
Becket  there  has  just  been  uncovered  a  wall  of  pre-Cambrian  limestone, 
where  the  limestone,  for  about  the  same  distance  in,  is  changed  in  the 
same  way  into  a  mass  of  matted  tremolite  fibers. 

4.  The  shearing. — The  peculiar  bed  at  the  quarry,  and  the  one  which 
promises  to  be  of  the  most  economic  importance,  is  the  central  band  of  the 
foliated  serpentine  marble,  which  seems  to  me  plainly  formed  by  the  shear- 
ing of  a  rock  like  the  black  spotted  marble  forming  now  the  eastern  band. 
The  former  enstatite  has  been  wholly  changed  to  serpentine,  often  to  an  oil- 
green  precious  serpentine,  but  every  stage  of  the  change  can  be  seen,  from 
that  in  which  the  black  enstatite  is  crushed  into  black  bands  between  layers 
of  limestone,  only  a  few  bronzy  cleavage  surfaces  remaining,  to  that  in 
which  the  long,  narrow  bands  and  spots  of  the  rich  green  serpentine,  with 
their  lighter  centers,  are  the  last  remnants  of  the  black  serpentinized  ensta- 
tites  with  their  gray  centers. 

5.  The  formation  of  the  enstatite. — The  bed  is  thus  traced  back  to  a  con- 
dition when  it  consisted  of  about  a  hundred  feet  of  a  white  crystalline 
limestone  mottled  with  enstatite  crystals,  and  an  adjoining  bed  to  the  west, 
60  feet  thick,  of  a  massive  rock  consisting  almost  wholly  of  the  same  coarse 


TOE  OHESTEK  AMPHIBOLITE  AND  SERPENTINES.  149 

crystals  of  eustatite,  of  about  the  same  size  and  proportions,  and  with,  as 
the  result  proved,  the  same  tendency  to  serpen tinizati on.  I  may  say  that 
transverse  sections  of  crystals,  from  both  the  massive  and  the  implanted 
forms,  show  the  prismatic  and  two  pinacoidal  cleavages  of  enstatite,  marked 
Avith  great  regularity  by  bands  of  black  magnetite  dust,  even  when  the 
whole  mass  is  completely  changied  to  serpentine. 

(a)  The  formation  of  the  enstatite  in  the  limestone  is  not  due  to 
dynamic  metamorphism. 

A  shearing  of  the  central  band  of  limestone,  which  has  promoted  the 
complete  destruction  of  the  enstatite  and  caused  the  thin  foliation,  is  very 
manifest.  No  one  can,  however,  examine  a  cubical  block  of  the  black 
mottled  marble,  where  the  long  rods  of  enstatite  run  in  all  directions 
without  crushing,  bending,  faiilting,  or  fibrous  development,  and  avoid  the 
conclusion  that  the  mass  was  free  from  internal  movements  during  and  since 
their  formation.  The  same  must  be  true  of  the  coarse  enstatite  rock,  found 
elsewhere,  made  up  of  long  interlaced  crystals.  They  must,  then,  have 
been  formed  since  the  erection  of  the  beds  into  their  present  vertical  posi- 
tion and  during  their  penetration  by  the  abundant  granite  dikes  which  cut 
them. 

(h)  The  development  of  enstatite  in  the  limestone,  and  of  the  cyanite 
in  the  schists,  coincides  geographically  with  the  spread  of  the  great  granite 
batholites. 

The  Chester  series — amphibolites,  serpentines,  pyroxenites,  enstatite 
rock,  serpentinic  and  dolomitic  limestones,  and  steatites — can  be  traced  from 
the  Hoosac  Tunnel  across  the  State,  and  in  great  loops  across  Granville,  to 
its  disappearance  south  of  Munn's  brook.  The  granitic  intrusions  extend 
westward  across  Granville  and  Blandford,  and  are  wanting  in  the  neighbor- 
hood of  the  band  farther  north.  Where  they  are  present  the  intenser  met- 
amoi-phism  of  the  schists  is  indicated  by  their  coarser  crystallization,  the 
lack  of  sericite,  and  the  great  abundance  of  cyanite,  which  of  all  the  purely 
aluminous  silicates  indicates  the  strongest  metamorphic  agencies. 

The  development  of  enstatite  in  the  limestone  is  also  coincident  with 
the  presence  of  the  granite,  and  represents  a  stronger  metamorphism  of  the 
dolomite  dependent  upon  its  influence,  and  the  most  northerly  appearance 
of  the  enstatite  and  coarse  pyroxenite  is  at  Osborn's  quany  in  Blandford, 
just  where  the  western  boundary  of  the  granitic  area  leaves  the  line  of  the 


150       GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

Chestei'  series  to  run  northeast.  North  of  this  point  the  rocks  of  the  series 
cease  to  be  influenced  by  the  granitic  metamorphism  which  followed  the 
dynamic  metamorphism  in  the  rocks  farther  southeast,  and  consist  entirely 
of  amphibolites,  partly  altered  to  serpentines,  and  tremolites  changed  to 
steatite,  while  the  inclosing  feldspathic  rocks  change  at  the  same  place  into 
sericite-schists. 

(c)  The  enstatite  of  the  black  serpentine  west  of  the  limestone  and 
that  in  the  limestone  must  have  had  the  same  origin. 

The  two  occurrences  are  identical  in  physical  peculiarities,  size,  shape, 
cleavage,  luster,  and  tendency  to  serpentinization,  and  under  the  microscope 
I  find  no  difference  in  them.  There  is  no  more  reason  for  giving  them  a 
different  explanation  than  in  the  case  of  the  separate  wernerite  crystals  in 
the  Bolton  limestone  and  the  massive  wernerite  rock  which  forms  'the 
border  of  the  crystalline  limestone  on  the  granite,  or  the  white  pyroxenes 
scattered  in  the  Canaan  limestone  and  the  compact  canaanite  into  which 
it  graduates,  or  the  bladed  tremolite  regularly  disseminated  in  the  Lee 
marble  and  the  compact  tremolite  rock  which  is  associated  with  it. 

In  all  these  cases  it  is  recognized  that  the  bladed  crystals  have  grown 
in  the  limestone  much  as  the  bladed  cyanites  have  grown  in  the  quartzose 
mica-schist  adjacent  to  our  serpentine,  and  that  the  only  further  assumption 
needed  to  explain  the  corresponding  massive  rocks  is  that  the  silicate  has 
in  each  case  replaced  all  the  carbonate,  or  that  the  solutions  which  brought 
the  silica  into  the  limestone  have  removed  the  surplus  of  the  carbonate.  It 
seems  to  me  that  the  natural  explanation  here  is  that  the  massive  enstatite 
rock  is  simply  the  result  of  carrying  the  process  which  has  formed  the 
enstatites  in  the  dolomite  a  step  farther  to  the  almost  complete  replacement 
of  the  latter;  and,  indeed,  within  what  we  have  called  the  limestone,  every 
stage  can  be  traced  from  pure  limestone  to  a  rock  nine-tenths  enstatite. 

(d)  The  enstatite  not  necessarily  a  proof  of  eruptive  origin  of  the 
rock. 

I  know  of  no  eruptive  rock  made  up  exclusively  of  coarse,  long-bladed 
enstatite,  but  I  have  studied  several  beds  of  such  character  among  the  crys- 
talline schists. 

I  have  collected  the  large,  smooth-faced,  altered  enstatite  crystals  in 
Norway,  and  they  seemed  to  have  formed  as  attached  crystals,  projecting 
into  free  spaces  in  crystalline  limestone,   rather  than  as  constituents  of 


THE  CHESTER  AMPHIHOLITK  AND  SERPENTINES.  151 

(.'niptiw  rock.  Also  the  enstatite  rock,  as  1  have  seen  it  at  the  Tilly  Foster 
mine,  is  a  nicniber  of  a  highly  nietamorphosed  crystalline-schist  series.  It 
resembles  quite  closely  what  the  Westfield  rock  may  have  been,  but  is  finer- 
grainerl. 

It  is  to  be  further  remarked  that  the  massive  structure  of  the  black 
serpentine  is  not  a  characteristic  indicating,  necessarily,  an  eruptive  origin, 
since  the  rock  is  made  up  of  elongated  square  prisms,  often  3  to  8 
inches  long,  interlaced,  and  with  calcite  in  the  interspaces.  It  is  like  the 
massiveness  of  the  Bolton  rock,  or  the  canaanite.  The  black  color  also  is 
wholly  the  product  of  serpentinization,  as  the  freshest  enstatite  is  every- 
where translucent  and  pale-gray. 

(e)  I  therefore  conclude  that  the  rock  was  once  a  bed  considerably 
thicker  than  the  present  one,  and  consisted  of  a  somewhat  ferruginous  dol- 
omite, which  was  permeated  by  heated  siliceous  solutions,  set  in  motion  by 
the  large  granite  batholites,  upon  their  intrusion  into  their  present  positions. 

The  ferruginous  enstatite  (the  serpentine  derived  from  it  contains  8  to 
9  per  cent  of  iron)  was  formed  b}^  the  reaction  of  these  solutions  with  the 
magnesium  of  the  carbonate,  and  the  resulting  carbonated  waters  may  have 
promoted  the  solution  and  removal  of  a  part  of  the  unaltered  calcium  car- 
bonate, and  this  may  have  been  the  condition  necessary  to  the  formation  of 
the  pm-e  enstatite  rock  of  the  west  wall,  which  differs  only  in  the  almost 
complete  absence  of  the  calcite.  The  analogy  of  the  wernerite -limestone, 
the  canaanite-limestone,  and  the  tremolite-limestone,  and  of  the  correspond- 
ing massive  silicate,  nearly  free  from  carbonate,  seems  to  me  complete  for 
the  explanation  of  the  enstatite-limestone,  and  of  the  massive  enstatite  of  the 
western  border  of  the  Westfield  quarry  and  the  similar  beds  farther  north. 
Indeed,  the  change  of  the  limestone  at  this  locality  into  tremolite,  for  a 
certain  distance  in,  along  the  eastern  border,  and  the  partial  change  into 
tremolite  throughout,  seems  not  essentially  different  from  the  earlier 
change,  for  a  greater  distance  inward,  into  enstatite. 

The  idea  that  the  black  serpentine  at  the  Westfield  quarry  is  an  altered 
dike  rock,  and  that  the  marble  only  is  an  altered  sedimentary  limestone,  I 
can  not  entertain  for  a  moment.  The  identity  of  the  black  prisms  in  the 
limestone  with  the  black  prisms  which  are  interlaced  to  form  the  massive 
rock  seems  to  me  fatal  to  this  theory,  especially  when  we  consider  those 
parts  of  the  limestone  which  are  nearly  all  composed  of  the  black  rods. 


152 


GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 


That  the  enstatite  can  have  passed  from  the  western  enstatite  rock  into 

the  limestone  is  improbable, 
for  the  fifty  feet  nearest  to 
the  enstatite  rock  contain 
much  less  of  the  enstatite 
than  do  the  next  thirt}^. 

At  Downey's  the  white 
limestone  is  free  from  ensta- 
tite, and  the  contact  with 
the  enstatite  rock  is  covered 
in  the  swamp.  At  Munn's 
brook  the  enstatite-limestone 
mixture  is  less  in  amount, 
and  the  enstatite  so  pre- 
dominates that  I  tried  to 
explain  the  whole  by  assum- 
ing that  the  black  serpen- 
tine (or  enstatite  rock)  was 
an  igneous  rock,  and  that  the 
serpentine-calcite  mixture 
(which  in  altered  surface 
specimens  could  not  be 
studied  so  well  as  in  the 
fresh  masses  opened  in  the 
Westfield  quarry)  was  de- 
rived from  the  eruptive  rock 
by  the  removal  of  some 
allotriomorphic  constituent 
and  the  interstitial  develop- 
ment of  a  later  secondary 
calcite  in  its  place.  A  sin- 
gle look  at  the  great  blocks 
of  the  black  spotted  marble 
in  the  quarry  will  prevent 
one  from  deriving  this  hun- 
dred feet  of  limestone  from 
any  alteration  of  an  eruptive  like  that  from  which  the  black  bed  may  have 


THE  CHESTER  AMl'HIBOLITE  AND  SEliPENTlNES.  153 

been  derived,  and  will  compel  one  to  hold  to  the  independence  of  the  two, 
if  one  will  not  accept  their  comniow  derivation  from  a  dolomite. 

G.  Derivation  of  the  black,  thin-fissile  ainphibolites  from  the  limestones. — 
If  the  steps  by  which  the  black  serpentine  has  been  traced  backward  in 
the  preceding-  sections  be  valid,  a  goodly  portion  of  the  series  for  20  miles 
from  the  Westfield  end,  and  in  places  its  whole  thickness,  was  originally 
a  dolomitic  limestone.  Associated  with  this  black  serpentine  series,  in 
gradually  increasing  quantity  as  Ave  go  north,  is  the  black,  or  dark-green, 
am])liibolite,  made  of  a  matted  network  of  actinolite  needles  in  an  albite 
mosaic.  The  two  series  are  closely  joined  in  all  this  distance;  they  replace 
each  other  along  dip  and  strike,  and  if  the  amphibolite  be  an  altered  erup- 
tive it  must  have  been  intruded  by  a  kind  of  preestablished  harmony,  so 
as  to  fit  itself  to  the  limestone  exactly  through  this  long  distance,  without 
showing  any  eruptive  relations  to  it  or  preserving  now  any  eruptive  rock 
texture. 

'Therefore,  as  in  the  case  of  the  same  amphibolites  which  in  the  same 
way  attach  themselves  to  the  pre-Cambrian  limestones  throughout  their 
whole  extent  in  Berkshire  County  (see  p.  29),  T  conclude  that  these  rocks 
are,  in  the  main,  derivatives  of  an  impure  argillaceous  limestone,  and  I 
extend  this  conclusion  to  the  long  range  of  amphibolite  which  goes  north 
from  Blandford  across  the  State,  interrupted  only  by  areas  of  serpentine 
derived  from  the  alteration  of  the  amphibolites.  The  residual  facts  which 
point  to  the  eruptive  origin  of  some  part  of  the  series  are  the  constant 
presence  of  chromium  and  nickel  in  the  serpentine  from  several  localities, 
as  indicated  in  the  table  of  analyses  on  page  116,  and  the  close  agreement 
in  composition  and  structure  of  the  dark  amphibolites  with  rocks  which 
have  been  proved  to  be  derived  from  basic  eruptives. 

In  relation  to  the  first  point,  it  is  very  probable  that  olivine-bearing 
rocks  may  be  present  in  the  serpentine  masses  north  of  the  Blandford  and 
Middlefield  olivine  occurrences,  though  long  search  in  the  field  and  the 
study  of  many  sections  has  compelled  me  to  refer  all  these  beds  to  the 
category  of  translucent  hornblendic  serpentine.  In  these  great  areas  of 
serpentine  much  may  have  been  overlooked,  as  sections  could  not  be  cut 
from  every  part.  The  presence  of  these  assumed  olivine  rocks  may  have 
been  the  initiating  cause  of  a  serpentinization  which  extended  far  beyond 
the  rock  in  which  it  started.  Further,  an  inspection  of  the  table  of  analyses 
shows  that  the  enstatite  and  sahlite,  minerals  which  have  certainly  formed 


154       GBOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 

in  the  limestone,  have  a  constant  content  of  chromium  and  nickel.  I  think 
we  may  therefore  assume  that  these  elements  have  been  concentrated  from 
extremely  dilute  solutions  in  and  by  the  limestone,  being  derived  pei'haps 
from  the  olivine  rocks,  and  that  they  do  not  necessarily  indicate  that  all  the 
minerals  which  now  contain  them  were  of  eruptive  origin. 

As  to  the  other  point,  I  find  it  very  difficult  to  establish  any  certain 
criteria  to  distinguish  amphibolites  derived  from  the  complete  alteration  of 
basic  eruptives,  or  their  tuffs,  and  tliose  derived  from  argillaceous  limestones, 
and  I  have  illustrated  the  difficulty  in  the  series  of  figures  on  Pis.  V  and  VI. 
Where  all  residual  structures  are  obliterated  two  rocks  may  become  indis- 
tinguishable. It  is  a  question  mainly  of  the  actiuolite  network  and  the  limpid 
and  untwinned  albite  mosaic  of  the  amphibolite.  The  actinolite  may  have 
either  origin,  and  every  stage  may  be  observed  from  tremolite-schists  cer- 
tainly metamorphic  to  actinolite  schists.  In  several  cases  I  have  found 
the  albite  mosaic  closely  like  the  untwinned  albite  growth  of  the  adjacent 
albitic  schists,  for  which  no  one  would  suggest  a  conneiction  with  eruptives; 
and  that  such  a  mosaic  may  readily  form  also  from  the  action  of  heated 
solutions,  on  a  diabase  is  shown  by  its  occurrence  in  the  red  Triassic  trap, 
described  in  Chapter  XIII.  It  is  rather  a  question  of  the  easy  formation 
and  solubility  of  albite  or  other  plagioclase  than  of  any  necessary  connec- 
tion Avith  a  basic  eruptive. 

7.  Formation  of  the  Chester  emery. — The  Chester  emery  may  have  been 
formed  by  the  replacement  of  a  jjortion  of  the  limestone  bed.  Just  as  great 
beds  of  limonite  with  gibbsite  and  allophane  have  formed,  by  replacement, 
at  the  surface  of  the  Stockbridge  limestone,  in  Berkshire  County,  and  of  the 
Bernardston  limestone  described  below,  so  the  formation  of  such  a  bed  at 
the  surface  of  the  former  Chester  limestone  would  explain  the  magnetite- 
emery  bed  which  now  caps  the  Chester  amphibolite. 

Metamorphic  agencies  have  changed  the  limonite  into  magnetite,  while 
the  hydrated  alumina  compounds  have  become  corundum,  and  continued 
alteration  has,  as  is  usual  with  corundum,  produced  many  interesting 
minerals. 

The  tourmaline  can  not  be  taken  as  a  fumarole  mineral  of  the  olivine 
rock,  since,  as  it  surrounds  the  emery  bed  in  great  quantity,  and  is  not  found 
in  association  with  the  olivine  rocks,  it  would  tend  to  prove  the  emery  bed 


THE  CUESTER  AMPIIIBOLITE  AND  SEKPENTINES.  155 

to  be  an  io-neous  rock,  viitlier  tlian  the  olivine  bed.  The  tourmaline  is,  as 
it  contains  much  magnetite,  a  ver}-  late-formed  mineral  in  the  fringe  rock, 
which  is  itself  a  late  product  of  metamorphism.  This  association  of  the 
emery  bed  with  limestone  may  point  to  a  similarity  of  origin  for  this  bed 
and  the  beds  of  Naxos,  which  are  thin  sheets  of  emery  in  crystalline  lime- 
stone associated  with  mica-schist  and  granite. 

8.  The  great  extent  and  constant  horizon  of  the  series  a  j^roof  of  its  sedi- 
mentarij  origin. — Above  and  below  the  Chester  amphibolite  series  are  highly 
tilted  sericite-schists  of  great  thickness,  often  very  quartzose,  which  were 
doubtless  once  sandstones,  of  about  the  same  age  as  the  Berkshire  and 
Grreylock  schists. 

The  Chester  series  is  conformable  with  these,  and  where  it  loops  up  to 
the  north  it  forms  a  compressed  syncline,  pitching  to  the  north,  and  east  of 
this  another,  more  open  syncline,  pitching  southerly.  It  has  the  aspect  of  a 
sedimentary  series,  and  not  that  of  an  intrusive  body,  and  its  complexity 
and  great  length  indicate  its  origin  by  sedimentation.  I  have  followed  it 
more  than  60  miles  in  Massachusetts  and  found  it  an  almost  uninterrupted 
band  of  amphibolite,  often  breaking  up  into  several  beds,  with  thin  inter- 
posed sericite-schists;  and  it  extends  a  great  distance  north  and  south, 
across  Vermont  and  Connecticut,  and  can  be  followed  far  east  into  Worces- 
ter County  at  a  constant  horizon. 

I  conclude,  then,  that  the  Chester  series  represents  an  eastward  expan- 
sion of  the  limestones  of  the  Silurian  sea  which  deposited  the  Stockbridge 
and  Bellowspipe  hmestone  in  Berkshire,  and  that  it  may  be  tentatively 
paralleled  with  the  latter  bed.  Some  very  basic  igneous  rocks  may  have 
been  associated  with  it  in  this,  its  shoreward,  extension,  and  along  its  central 
part  its  upper  surface  was,  at  a  later  time,  replaced  locally  by  limonite. 

The  Bolton  limestone  in  Worcester  County  occupied  about  the  same 
horizon,  and  has  in  places  changed  into  actinolite-schists  and  developed  in 
large  quantity  boltonite,  which  is  almost  a  variety  of  olivine,  and  is  in 
places  changed  into  black  serpentine,  forming  a  rock  exactly  like  the  West- 
field  quarry  stone.  The  black  prisms  of  altered  boltonite  scattered  in  the 
white  limestones  reproduce  on  a  slightly  smaller  scale  the  black  rods  of 
enstatite'  in  the  latter  rock. 


156  GEOLOGY  OF  OLD  HAMPSHIEE  COUiJTY,  MASS. 

THE  SAVOY  SCHIST— THE  UPPER  SEBICITE-SCHIST. 

DISTRIBUTION. 

A  broad  band  of  sericite-schist  enters  the  State  from  Vermont  across 
the  eastern  half  of  Rowe  and  the  whole  of  Heath,  and  as  it  crosses  Charle- 
mont  it  extends  over  into  Berkshire  County.  It  occupies  the  western  half 
of  Hawley,  Plainfield,  and  Cummington,  where,  much  narrowed,  it  comes 
again  wholly  within  the  limit  of  Hampshire  County. 

It  runs  south  in  a  narrow  band,  1  to  2  miles  wide,  of  nearly  vertical 
strata  or  of  strata  with  high  easterly  dip,  across  Middlefield,  Chester,  and 
Blandford,  and  in  the  latter  town  expands  broadly  eastward  across  this  town 
and  Russell,  attaining  a  width  of  aboVe  7  miles.  It  divides  and  wraps  around 
the  Hoosac  schist  below,  and  extends  south  across  Granville  in  two  bands 
in  the  east  and  west  parts  of  this  town,  on  either  side  of  and  dipping  away 
from  the  older  formation.  The  East  Grranville  gneiss  thus  forms  the  nucleus 
of  an  anticline  having  its  axis  inclined  to  the  north,  so  that  the  Hoosac  and 
Rowe  schists  and  the  Chester  amphibolite,  and  finally  the  Savoy  schist, 
appear  in  succession  on  either  flank.  On  the  east  the  succession  can  not  be 
followed  higher,  as  the  Savoy  schist,  which  forms  the  long  ridge  of  Sodom 
Mountain,  has  at  its  foot  the  sandstones  of  the  Trias,  covered  mostly  by  the 
Glacial  and  post-Glacial  beds.  On  the  west  the  Savoy  schist  is  a  closely 
folded  syncline,  bounded  by  the  amphibolite  band  (Chester)  on  either  side, 
and  doubly  looped  to  include  Liberty  Hill  and  Sweetman  Mountain,  and 
running  out  to  the  south  before  reaching  the  State  line.  (See  map, 
PL  XXXIV.) 

On  the  north,  where  it  broadens  out  so  suddenly  in  folding  round  the 
north  end  of  the  anticline,  it  dips  under  the  Goshen  spangled  mica-schist, 
and  the  axis  of  the  anticline  is  continued  northward  beneath  the  latter,  and 
by  an  upward  undulation  brings  up  the  Savoy  schist  in  an  interesting 
faulted  quaquaversal  in  the  middle  of  Goshen,  and  again,  farther  north, 
brings  up  once  more  by  a  stronger  upward  curve  the  underlying  Cambrian 
gneiss  at  Shelburne  Falls. 

BOUNDARY  UPON  THE  ROCKS  BELOW. 

Where  the  Chester  amphibolite  band  is  present  in  force  as  a  single 
massive  bed,  as  across  Rowe,  Chester,  and  Granville,  the  transition  between 
the  two  is  very  sudden. 


THE  SAVOY  SCHIST.  157 

Across  Blandford,  where  the  beds  are  much  covered,  and  where,  while 
many  Ixuls  of  sericite-schist  intervene  in  the  Chester  amphibolite,  the  pre- 
dominant rock  is  hornblende-schist,  the  boundary  is  less  clear,  and  here,  on 
the  one  hand,  hornblendic  bands  appear  in  abundance  all  through  the 
hydromica-schist  series,  and  on  the  other  the  intercalated  schists  mentioned 
above  are  identical  with  the  schists  of  the  upper  series ;  but  this  boundary 
is  of  somewhat  subordinate  importance,  and  the  Chester  amphibolite  already 
described,  although  fully  deserving  separate  treatment,  both  from  its  impor- 
tance as  a  horizon  and  from  the  geological  interest  of  its  various  members, 
is  quite  closely  allied  to  the  present  series,  and  the  most  important  boundary 
line  lies  at  the  base  of  the  latter.  Around  the  Granville  anticline  and  north 
of  Middlefield,  where  the  amphibolite  band  narrows  and  is  interrupted,  the 
boundary  is  drawn  with  less  but  still  with  very  satisfactory  accuracy. 

GENERAL    DESCKIPTION   OP   ROCKS. 

The  prevailing  rock  is  a  muscovite-schist  of  medium  to  coarse  grain, 
with  varying  but  always  considerable  content  of  mica,  and  as  this  mineral 
is  very  generally  hydi-ated  the  whole  series  was  for  a  long  time  called 
talcose  schist,  from  the  soapy  feel  of  the  softened  mica.  The  rock  is  of 
a  light-gray  or  greenish-gray  color,  and  both  carbonaceous  and  ferru- 
ginous matter  in  such  form  as  to  darken  the  rock  are  very  generally 
absent — a  general  mark  of  distinction  between  this  and  the  subsequent 
formation. 

Almandine  garnet  is  very  generally  but  very  irregularly  present,  often 
crowding  the  strata  for  great  thickness  and  often  wholly  wanting.  The 
forms  202  (211);  202  (211),  oo  0  (110);  and  oo  0  (110)  appear.  The  gar- 
nets frequently  reach  large  size — 25-35™" — and  in  several  places,  especially 
in  Chester,  afford  fine  cabinet  specimens.  They  are  often  changed  to  the 
center  into  chlorite,  and  this  mineral  also  often  appears  in  scales,  especially 
stretched  in  long  lines  along  the  cleavage  faces  of  the  rock,  giving  the 
schist  a  greenist  tint,  and  so  far  increases  at  the  expense  of  the  mica  as  to 
become  a  chlorite-schist. 

The  sericite-schist  further  carries  white,  sugary  sandstone  beds  shot 
through  with  long,  flat  crystals  of  black  hornblende,  which  forms  a  striking 
rock  in  the  cutting  nearest  the  Chester  staiion  and  appears  abundantly 
farther  south  in  Blandford.     This  increases  at  the   expense   of  the  other 


1 58       GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

constituents  until  a  hornblende-schist  is  formed,  made  up  of  jet-black  needles 
of  hornblende  and  a  little  quartz  and  albite,  which  differs  from  the  heavy 
bed  of  amphibolite  below  in  its  deeper  color,  the  lack  of  visible  epidote, 
and  its  more  friable  texture.  Scattered  through  the  series,  however,  are 
other  beds  of  hornblende-schist  which  do  not  materially  differ  from  the 
basal  bed. 

A  light-green  pyroxenite,  more  or  less  calcareous,  forms  small  beds  of 
a  tough,  massive  rock  at  various  points  throughout  the  whole  extent  of  the 
formation.  This  rock  was  noted  by  President  Hitchcock  under  the  name 
augitic  gneiss. 

At  its  southern  extremity,  in  Grranville  and  Russell,  the  beds  become, 
as  an  exception,  somewhat  feldspathic,  and  biotite  and  cyanite  associate 
themselves  with  the  muscovite.  In  the  railroad  cuts  east  of  Russell  station 
occur  beds  of  a  rather  coarse  schist  in  which,  on  the  lamination  faces,  the 
bright  black  biotite  is  intergrown  with  the  muscovite,  the  latter  surrounding 
the  former,  and  the  basal  cleavages  being  common. 

COMPARISON   WITH    THE    EOWE    SCHIST    BELOW. 

The  two  formations  agree  in  the  prevalence  of  muscovite-schists,  and 
the  hydration  of  the  mica  is  a  phenomenon  common  in  the  older  series, 
notably  where  the  Chester-Becket  road  crosses  the  town  line  and  northward 
across  the  State,  and  then  a  rock  exactly  like  the  prevalent  one  in  the 
higher  series  results.  The  feldspathic  character  of  the  lower  series  is  not 
at  all  projected  into  the  other,  and  the  green  tint  of  the  upper  beds  due  to 
chlorite  and  to  the  intercalated  bands  of  hornblende  and  chlorite-schist 
differentiate  the  two  abundantly.  Stratigraphically  there  is  no  trace  of 
any  break  between  the  two,  and  as  there  is,  as  already  described,  a  well- 
marked  break  between  the  Hoosac  feldspathic  mica-schist  and  the  Becket 
gneiss  below,  and  a  probable  one  at  the  top  of  the  Savoy  schist,  the 
Hoosac,  Rowe,  and  Savoy  schists  are  more  nearly  allied  to  one  another 
than  is  any  one  of  these  to  the  adjoining  series  above  and  below. 

DETAILED    DESCRIPTION    AND    SECTIONS. 

The  facies  of  the  formation  changes  greatly  from  north  to  south.  At 
its  southern  extremity  the  two  arms  which  pass  through  Granville  are 
made  up  of  a  coarse  two-mica,  slightly  feldspathic  schist,  rusty,  and 
over  large  areas  barren  of  accessory  minerals,  and  much  cut  up  in  many 


THE  SAVOY  SCHIST.  159 

places  by  veins  and  irregular  patches  of  coarse  granite.  It  sometimes 
abounds  in  coarse  cyanite  blades. 

In  Sodom  Mountain,  in  East  Granville,  the  same  rock  pi-evails.  Unim- 
portant bands  of  hornblende-schist  occur,  and  a  bed  of  the  pale-green  cal- 
careous pyroxenite,  very  probably  an  altered  impure  limestone  bed,  was 
observed  by  President  Hitchcock'  and  catalogued  as  augitic  mica-slate. 
The  rock  here  very  closely  resembles  the  Amherst  rusty  feldspathic  mica- 
schist. 

Northward  through  Blandford  the  rock  gradually  ceases  to  contain 
biotite  and  feldspar  as  constant  and  important  constituents,  becomes  gray 
and  more  siliceous,  and  the  muscovite  is  generally  hydrated.  It  is  much 
corrugated  in  this  area,  and  doubtless  contains  many  subordinate  folds  and 
great  flutings,  which  could  in  some  cases  be  traced  for  considerable  dis- 
tances, and  to  which  I  devoted  much  labor,  but  without  reaching  results 
which  could  be  entered  upon  the  map. 

If  from  Granville  we  go  north  through  Russell,  east  of  Blandford,  and 
thus  through  the  eastern  half  of  the  broad  expansion  of  the  formation,  we 
find  that  the  Granville  feldspathic  facies  persists  much  farther  north  and 
would  seem  to  belong  to  the  lower  portion  of  the  series  here  discussed. 
Northward  it  is,  nearly  to  the  Westfield  River,  a  coarse,  rusty  muscovite- 
schist,  often  biotitic,  often  a  little  feldspathic,  and,  indeed,  may  be  called  a 
coarse  membranous  gneiss,  the  continuous  folia  or  membranes  of  mica  being 
separated  by  thick  sheets  and  lenses  of  quartz  with  a  little  feldspar. 

As  before  (see  p.  85),  a  somewhat  detailed  description  is  given  of  the 
development  of  the  series  along  the  Westfield  River,  which  in  Chester  runs 
down  across  this  series,  making  an  acute  angle  with  the  strike,  and  then, 
crossing  the  southward  prolongation  of  the  Conway  mica-schist,  again 
enters  this  formation  and  runs  for  a  long  distance  through  Huntington 
and  Russell,  across  the  head  of  the  eastern  anticline. 

In  Chester  the  rock  is  already  a  chloritic  sericite-schist,  of  a  type  which 
continues  a  long  way  north;  flat,  thin-fissile  into  plates  10-15°"°  thick,  with 
the  micaceous  minerals  concentrated  mostly  on  the  lamination  planes; 
uniformly  light-gray  with  a  shade  of  green  from  the  presence  of  scales 
of  chlorite  mixed  with  the  muscovite,  and  these  can  be  detected  with  the 
microscope  when  they  are  not  visible  to  the   eye;    at  other  places  this 

'No.  2113,  Catalogue  of  State  Collection;  Geology  of  Massachusetts,  1841,  p.  814. 


160 


GEOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 


increases  and  the  cleavage  surfaces  are  mottled  by  large  aggregations  of 
the  green  mineral.  The  thickness  of  the  plates  is  made  up  of  highly  crys- 
talline quartz,  at  times  fused  into  a  complete  vein  quartz  and  carrying 
garnets  and  pyrites,  often  in  large  quantities.  It  is  frequently  also  wholly 
barren  over  broad  areas. 

To  the  east  of  the  great  serpentine  bed  in  the  north  of  Chester  the  rock 
is  gnarled  and  contorted  in  a  most  marvelous  manner;  the  quartz  laminae 
branch  out  and  grow  thin  in  rapid  alternations,  and  many  small  quartz  veins 
run  in  all  directions.  This  holds  for  a  half  mile  eastward,  until,  on  the  first 
road  running  north,  the  corrugation  lessens  suddenly  and  disappears,  and 
the  schist  takes  the  normal  form  described  above. 

Several  beds  of  amphibolite,  7  to  12  feet  thick,  are  interposed  in  the 
schist,  and  the  transition  from  one  to  the  other  is  in  all  cases  very  sudden. 

The  succession  of  the  beds  next  above  is  well  shown  in  the  second 
cutting  north  of  Chester  station,  and  the  section  is  given  in  detail  to  show 
the  rapid  and  repeated  alternations  of  micaceous  and  hornblendic  strata. 
The  section  runs  from  below  upward: 

Sectiort  north  of  Chester  station. 


Feet. 

Sericite-schist   3 

Amphibolite  -  - 1 

Sericite-schist 1^ 

Amphibolite 2 

Sericite-schist 1 

Amphibolite 2 

Sericite-schist 3^ 

Amphibolite ^ 

Sericite-schist ....  3 


Feet. 

Amphibolite 6 

Sericite-schist 8 

Amphibolite 10 

Sericite-schist 6 

Amphibolite 6 

Sericite-schist 12 

Amphibolite 4 

Sericite-schist 6 


A  very  short  distance  separates  this  section  from  the  cutting  nearest 
the  station,  representing  the  strata  next  above  those  just  described.  This 
cutting  exposes  217  feet,  and  in  this  distance  are  23  beds,  from  1  to  20  feet 
in  thickness,  of  alternating  sericite  and  amphibolite.  (See  PI.  VI,  fig.  4, 
p.  306.)  Many  of  the  sericite-schist  layers  contain  in  abundance  large,  dis- 
tant garnets  in  every  stage  of  change  to  chlorite. 

Following  the  line  eastward  from  the  station  to  the  junction  with  the 
Conway  mica-schist  the  greenish-gray  sericite-schist  in  this  upper  portion, 


THE  SAVOY  SCHIST.  161 

almost  free  from  amphibolite,  is  flat-bedded  and  jjresents  a  rather  monoto- 
nous area  of  vertical  beds,  with  strike  varying-  httle  from  the  meridian. 

North  of  Chester  the  series  occupies  a  position  on  either  side  of  the 
hne  between  Middlefield  and  Worthington,  being  about  half  in  each  of 
these  towns,  exposed  on  the  slopes  of  one  of  the  most  characteristic  deep 
V-shaped  longitudinal  valleys  so  common  in  the  Berkshire  Hills. 

The  facies  of  the  series  has  changed  greatly,  and  starting  from  its  base 
at  the  serpentine  and  soapstone  bed  at  Harold  Smith's,  in  the  north  part 
of  Middlefield,  which  is  plainly  the  continuation  of  the  great  bed  in  the 
south  of  this  town,  instead  of  the  interminable  alternation  of  sericite-schist 
and  hornblende-schist  beds  noted  above  in  Chester,  one  crosses  a  great 
thickness  of  the  vertical  sericite-schists,  often  very  quartzose,  often  garnetif- 
erous,  but  without  much  hornblende  until  the  top  of  the  series  is  reached. 
Through  the  whole  length  of  the  town  of  Worthington  the  conditions  are 
remarkably  uniform,  and  the  section  along  the  road  from  Peru  to  Worthing- 
ton Center  may  be  given  as  a  sample  of  the  whole  distance. 

At  the  cemetery,  160  feet  east  of  the  Peru  line,  the  Becket  gneiss 
gives  place  to  the  Hoosac  albitic  mica-schist,  coarse,  coi'rugated,  rusty,  and 
carrying  at  times  large  garnets,  and  just  before  the  bed  of  the  Middle 
Branch  of  the  Westfield  River  is  reached  a  layer  115  feet  thick  of  a 
bright-green,  fissile  chlorite-schist  appears  at  the  base  of  the  present 
series  and  replaces  the  usual  serpentine  and  hornblende  bed — the  Chester 
amphibolite. 

Up  the  sharp  hillside  eastward,  near  the  house  of  W.  Starkweather,  the 
beds,  as  made  out  along  the  road  and  for  a  long  distance  north  and  south, 
are  of  coarsely  corrugated  sericite-schist,  often  a  quartz-schist  with  films  of 
hydrated  mica,  and  rarely  a  band  of  soft,  deep-green,  slaty  chlorite-schist, 
the  whole  dipping  90°  and  aggregating  720  feet. 

East  of  this  house  the  same  schists,  often  very  quartzose,  continue  and 
carry  five  beds  of  hornblende-schist,  3  to  10  feet  thick.  The  whole  series 
is  3,280  feet  thick. 

North,  across  Plainfield  and  Hawley,  a  great  mass  of  barren,  monot- 
onous quartzose  sericite-schists  expand  to  a  considerable  width  and  occupy 
the  almost  inaccessible  hill  region  drained  by  the  Cold  River  They 
preserve  this  habit  where  they  are  deeply  cut  by  the  Deerfield  River,  from 
Hoosae  Timnel  to  Zoar.     Rarely  a  hornblendic  bed  appears  near  the  base. 

MON  XXIX 11 


162  GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

Thev  impress  themselves  strongly  on  tlie  topography  as  they  bend  north- 
east from  Zoar,  in  Adams  Mountain,  but  preserve  their  uniform  habit  to  the 
State  line. 

THE    SHELBURNE    ANTICLINE. 

This  anticline  is  distinguished  strongly  from  the  more  southern  one  by 
the  absence  of  the  sericlte-schist,  the  calciferous  mica-schist  being  separated 
from  the  gneiss  by  only  a  band  of  hornblendic  rock  of  no  great  thickness, 
with  merely  a  suggestion  of  the  Rowe  schist  below. 

PETKOGRAPHICAL   DESCRIPTION. 

Mica-schist  from  near  School  No,  6,  Charlemont.  Rather  coarse,  light- 
gray  rock,  with  shining  muscovite  scales  and  distant  large  garnets. 

Feldspar  can  be  seen  rarely  with  the  lens.  One  piece  gave  extinction 
-|-15°  '60'  in  the  plane  of  oo  P  o)  (010)  when  measured  from  the  edge  M  t, 
and  was  therefore  albite.  Another  gave  extinction  +2°  30',  and  was 
therefore  oligoclase  (Aba  Aiii). 

The  feldspar  is  present  in  small  amount.  The  garnets  are  crowded 
with  impurities  and  polarize  distinctly. 

Garnetiferous  sericite-schist  from  Chester.  Railroad  cutting  west  of  sta- 
tion. A  pale  greenish-gray  rock,  with  greasy  continuous  films  of  hydrated 
muscovite  between  thin  layers  of  rather  coarse-granular  quartz,  full  of 
pale-red  garnets. 

Under  the  microscope  the  angularly  granular  quartz  abounds  in 
rounded  grains  of  magnetite,  and  these  two  minerals  fill  the  garnets,  mag- 
netite being  more  abundant  in  the  garnet  than  outside.  The  muscovite  is 
in  twisted  films  and  radiates  in  broad  plates  from  the  garnets.  The  latter 
send  out  abundant  amoeboid  processes  among  the  quartz  grains. 

Beautiful  triangular  and  doubly  terminated  tourmalines  of  greenish- 
brown  color  show  exquisite  absorption — deep  crimson  at  one  end,  shadiiig 
to  emerald-gi-een  at  the  other,  or  to  the  middle,  when  the  green  shades  into 
smoke-brown  at  the  other  end.  They  are  thus  miniature  reproductions 
of  beautiful  crystals  from  Paris,  Maine.  On  rotation  the  colors  change 
places.  A  few  bright-green  chlorite  scales  appear.  The  order  of  formation 
is:  magnetite,  tourmaline,  quartz,  garnet,  chlorite,  muscovite,  while  the 
quartz  has  formed  and  re-formed  and  some  of  the  present  grains  inclose  all 
the  other  constituents. 


THE    IIAVVLEV    SCHIST.  1(;3 

All  the  pyroxene  rocks  described  below  are  i)lainly  altered  limestone 
beds  in  the  schist,  and,  though  common,  never  reach  large  dimensions. 

I'l/roxenc-schisf  from  Heath.  No.  203,  Massachusetts  Survey  Collection. 
"Augite  mica-schist."  Large,  pale-green  pyroxenes,  with  irregular  outlines, 
inclosing  many  quartz  veins,  and  placed  in  a  coarse-granular  quartz  mass, 
with  much  biotite  and  magnetite. 

Pyroxenic  limestone  from  Sodom  Mountain,  Southwick.  No.  202,  Massa- 
chusetts Survey  Collection.  "Augitic  mica-slate."  Gives  abundant  efferves- 
cence in  cold  HCl,  which  is  renewed  on  heating.  A  thin  layer  of  calcareous 
coccolite  between  two  layers  of  quartz,  the  whole  inclosed  in  mica-schist. 

The  slide  shows  the  pale-green  pyroxene  changing  into  a  white  asbestos. 

Pyroxenic  limestone  from  Russell ;  railroad  cut,  east  of  station  and  just 
west  of  G.  Frost's.  A  layer  3  feet  thick,  of  a  very  tough,  fine-grained, 
reddish  rock,  showing  much  calcite,  garnet,  pyrite,  and  titanite.  In  the  slide 
sahlite  is  abundant,  actinolite  rare. 

INTRUSIVE   ROCKS. 

In  its  southern  portion,  through  Granville,  many  pegmatite  or  coarse 
muscovite-granite  veins  and  masses  penetrate  the  schist,  especially  in  Sodom 
Mountain,  and  the  same  is  true  in  a  lesser  degree  through  Blandford,  where, 
near  Mr.  Osborn's,  the  fine  rose  quartz  veins  are  associated  with  coarse 
granite  in  this  series,  and  in  the  south  edge  of  the  village,  whei'e  the 
deeply  rotted  beds  have  been  much  quarried  for  kaolin.  Farther  north, 
across  Chester,  Middlefield,  and  Worthington,  these  coarse  granitic  vein 
stones  are  almost  or  altogether  wanting. 

In  the  east  of  Middlefield,  and  wholly  isolated,  an  enormous  dike  of 
porphyritic  granitite  runs  north  and  south  nearly  the  whole  length  of  the 
town,  with  a  width  in  places  of  1,300  feet.  It  is  a  rock  not  unlike  the  New 
Hampshire  "porphyritic  gneisses,"  but  the  feldspars  are  somewhat  smaller, 
10-15"""  in  length.     Farther  north  granite  is  wanting. 

THE   HAWLEY   SCHIST. 

This  would  have  been  called  by  Percival,  in  his  quaint  but  very  effect- 
ive nomenclature,  "a  ferromagnesian  formation."  The  most  prevalent  rock 
is  a  dark-green,  soft,  chloritic  schist,  generally  crowded  with  porphyritic 


164  GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

crystals  of  brown  ankerite,  which  are  usually  in  grains  a  fraction  of  an  inch 
across,  but  at  times  are  perfect  rhombohedra,  more  than  an  inch  in  size. 

The  quartzose,  pale-green  muscovite  or  sericite-schist,  common  in  the 
formation  below,  appears  here  also,  but  it  is  usually  spotted,  especially 
on  the  cleavage  faces,  with  groups  of  long  blades  of  black  hornblende,  often 
6  inches  in  leno'th,  which  are  radiated  on  the  foliation  faces  of  the  schist 
from  a  central  area,  after  the  fashion  of  a  sheaf  of  wheat,  from  which  circum- 
stance President  Hitchcock  named  the  mineral  fasciculite.  Although  the 
name  has  passed  into  the  list  of  synonyms,  I  have  found  it  useful  as  a  desig- 
nation of  the  sericite-  and  chlorite-schists  in  which  these  hornblende  blades, 
often  in  sheafs,  appear  as  quasipoi-phyritic  inclusions  which  have  the  habit 
of  a  somewhat  constant  accessory,  rather  than  of  an  essential  constituent, 
of  the  rock  in  question.  There  are  thus  fasciculite-chlorite-schists  and 
fasciculite-sericite-schists ;  but  this  very  generally  disseminated  hornblende 
has  been  ignored  in  mapping,  and  the  large  amphibolite  beds  which  are 
represented  on  the  map  are  black,  purely  hornblendic  schists,  free  from 
any  visible  micaceous  mineral.  This  general  distribution  of  hornblende 
distinguishes  the  Hawley  formation  or  series  from  the  beds  which  precede 
and. follow  it,  wherein,  outside  of  the  amphibolite  beds,  hornblende  is  very 
rare  and  for  the  most  part  wanting  altogether.  None  of  the  hornblendic 
bands  in  this  series  show  any  tendency  to  serpentinization. 

DISTRIBUTION. 

The  band  enters  from  the  southwest  comer  of  Halifax,  Vermont,  with  a 
width  of  a  mile,  and  begins  at  the  Davis  mine  to  widen,  crossing  the  Deerfield 
River  with  a  width  of  3  miles.  It  goes  across  Hawley  with  this  width,  and 
is  bounded  on  the  west  by  a  great  fault.  As  it  enters  Plainfield  the  Groshen 
schists  begin  to  overlap  it  rapidly,  and  it  crosses  this  town,  Cummington, 
and  Worthington  with  a  width  of  half  a  mile.  As  it  enters  Chester  a  second 
overlap  of  the  Goshen  schist  cuts  it  off  entirely.  Farther  south  no  series 
possessing  its  lithological  peculiarities  and  richness  in  iron  can  be  found. 

DETAILED    DESCRIPTION. 

The  whole  eastern  slope  of  the  deep  valley  that  separates  Middlefield 
and  Worthington  is  underlain  by  the  rocks  of  this  series,  and  the  large 
garnets,  superficially  changed  to  chlorite,  and  the  slabs  of  fasciculite  furnish 
many  attractive  specimens  for  the  cabinet. 


THE   HAWLEY    SCHIST.  165 

111  continuation  eastward  of  tlie  section  of  the  Savoy  schist  given  ou 
page  161,  one  iinds  that  the  barren  Savoy  schist  is  followed  by  a  great  devel- 
oj^raeut  of  amphibolite  (1,640  feet  thick),  the  upper  half  made  up  almost 
entii'ely  of  this  rock,  the  lower  part  containing  some  unimportant  beds  of 
sericite-schist  and  biotite-schist,  and  layers  of  a  coarse,  yellow  sericite- 
schist  with  "fasciculite,"  and  all  grading  into  amphibolite.  The  prevailing 
rocks  are:  (ffl)  a  dark-brown  hornblende-  (cummingtonite-)  schist,  with  very 
fine  lamination,  which  is  brought  out  more  distinctly  by  weathering;  (h)  a 
gray,  micaceous  hornblende-schist;  (c)  layers  of  very  fissile  chlorite-schist. 
This  is  followed  by  a  series  (656  feet  thick)  of  thin-fissile,  very  fine-grained, 
friable,  dark-gray  mica-schists,  made  up  almost  wholly  of  muscovite,  and 
without  accessories;  this  band  can  be  followed  clear  across  the  town  of 
Worthington  and  lies  beneath  the  undoubted  flaggy  schists  of  the  next 
series  (Goshen),  to  which  I  have  usually,  but  with  some  hesitation,  referred 
it.     The  whole  thickness  is  2,296  feet. 

The  above  distances  are  approximate,  being  measured  along  a  nearly 
straight  east-west  road,  the  strata  being  vertical  and  striking  north  and  south. 
Across  Cummington  the  beds  abound  in  fasciculite,  chlorite,  and  scattered 
grains  of  ankerite,  or  of  rust  spots  which  mark  the  removal  of  the  latter. 

Fifty  rods  east  of  A.  W.  Brown's  sawmill,  near  the  west  village,  these 
sericite-schists  with  fasciculite  and  ankerite  are  followed  on  the  east  by 
thin-bedded,  light,  sandy  mica-schists,  and  these  by  a  thin  bed  of  porphyritic 
amphibolite,  above  which  are  50  rods  of  graphitic  pimpled  schists,  which 
one  must  associate  with  the  Goshen  mica-schist;  then  comes  a  2-foot 
layer  of  amphibolite,  and  then  the  Goshen  mica-schist  continues  eastward. 
This  is  the  beginning  of  a  new  peculiarity,  at  the  boundary  between  the 
two  series,  which  continues  and  grows  more  marked  northward — a  heavy 
bed  of  amphibolite  near  the  top  of  this  series,  another  equally  heavy,  but 
of  different  habit,  occurring  near  the  bottom  of  the  higher  series,  and  both 
increasing  in  thickness  northwardly.  Across  Plainfield  and  Hawley  the 
conditions  remain  unchanged.  The  main  bed  of  amphibolite  at  the  top  of 
the  Hawley  series  grows  thicker,  and  is,  I  doubt  not,  more  continuous  than 
can  be  made  out  from  the  outcrops  in  this  drift-covered  region.  Other 
beds  of  amphibolite  occur  lower  down,  and  the  beds  carrying  chlorite, 
fasciculite,  and  ankerite  increase,  so  that,  measured  across  the  middle  of 
Hawley,  they  occupy  a  full  half  of  the  width  of  the  town,  and  the  series  is 
here  at  its  widest. 


166  GEOLOGY  or  OLD  HAMPSHIRE  COUN'IY,  MASS. 

This  is  well  seen  in  going  east  from  the  Hawley  iron  mine.  West  of  the 
ore  bed  the  rock  is  the  common  quartzose  sericite-schist  (Savoy).  The  ore 
bed  itself  is  a  hematite-schist  (itabirite),  made  up  of  beautifully  corrugated 
scales  of  micaceous  hematite,  which  can  be  followed  on  the  strike  more  than 
a  mile.  The  pure  hematite  reaches  scarcely  a  foot  in  thickness.  Includ- 
ing the  quartz-hematite-schist  the  visible  thickness  was  not  above  3  feet, 
but  from  the  width  of  the  open  workings  of  the  bed,  now  filled  with  water, 
the  thickness  would  seem  to  have  been  in  places  more  than  twice  as  much. 

Going  east  down  the  long  hillside,  and  with  the  dij)  of  the  steeply 
inclined  beds,  one  finds  a  great  thickness  of  chloritic  schists,  so  abounding 
in  yellow  ankerite  in  grains  that  the  latter  mineral  often  makes  more  than 
half  its  mass,  and  near  the  surface,  where  it  is  weathered  out,  the  rock  is 
often  a  friable  mass,  somewhat  rusty.  At  the  foot  of  the  hill  is  a  great 
development  of  amphibolite,  and  much  of  the  sericite-schist  abounds  in  the 
sheaf-like  hornblende  aggregates  or  fasciculite,  and  this  description  holds 
true  clear  across  the  town  to  the  upper  boundary  of  this  series.  North 
through  Gharlemont  and  Rowe  to  the  State  line  great  beds  of  chlorite-schist, 
often  dolomitic,  and  of  hornblende-schist,  sometimes  with  calcite,  abound 
(as  just  west  of  Gharlemont  station),  and  the  sericite-schist  itself  is  often  a 
fasciculite-schist. 

PETROGRAPHICAL    DESCRIPTION. 

The  jet-black,  thin-fissile  hornblende-schists  of  this  series  do  not 
materially  differ  from  those  found  below.  Two  specimens  were  chosen  for 
sjDecial  microscopical  examination,  and  one  of  these  has  also  been  analyzed. 

Porphyritic  epidote-amphihoUte  from  northeast  of  E.  Gleason's,  Heath 
(see  PI.  VI,  fig.  3,  p.  306).  A  dull-black,  fissile  rock  made  up  of  matted  needles 
visible  to  the  eye,  doubly  porphyritic,  with  black,  stout  hornblendes  and  long, 
rectangular,  white  plagioclase  crystals  with  greasy  luster  from  the  abundant 
epidote  inclusions.  With  common  light  the  stout  hornblende  sections  show 
a.  peculiar  dichroism.  The  basal  sections  are  of  a  yellow  color,  similar  to 
that  shown  by  the  same  sections  with  polarized  light  vibrating  parallel  to 
a,  and  the  longitudinal  sections  a  green  like  that  seen  parallel  to  c.  They 
have  a  clear  border,  but  the  center  is  so  full  of  inclusions  as  to  give  a 
mosaic  of  brilliant  color.  Small  hornblendes,  epidote,  biotite,  and  ankerite 
abound.  Tlie  hornblendes  are  twinned,  with  extinction  21°  on  either  side 
of  the  suture,  and  show  strong  absorption  colors:  x;  =  blue,  tr  =  olive-green. 


TII1<]    UAVVLIOY    SOmST. 


167 


;i  =  hrio'ht  yi'Uow,  b>>c>ix.  The  colorless  })lienocrysts  are  small,  single 
twins  of  albite,  extinguishing  at  about  2°  on  either  side  the  center.  With  a 
lens  thev  are  seen  to  be  frosted  full  of  small  grains  of  epidote,  and  scales, 
apparently  of  muscovite.  With  polarized  light  these  make  a  mosaic  of  such 
brilliant  color  that  only  a  trace  of  the  polarization  of  the  feldspar  is  visible. 
In  a  section  parallel  to  oo  P  oc  (100)  a  negative  obtuse  bisectrix  was 
observed.  The  large  rhombs  of  ankerite  with  rust-marked  cleavage  appear 
everywhere.  Magnetite  is  abundant  in  small,  rounded  grains  without  alter- 
ation products.  The  background  is  a  mosaic  of  small,  short  hornblende 
blades  and  magnetite,  epidote,  and  feldspar  grains.  It  forms  most  beautiful 
microscopic  slides. 

Black,  fissile  amphiholite  from  Worthington,  west  of  G.  Sherman's. 
Nearly  all  a  network  of  large  blades  of  hornblende,  with  finely  marked 
prismatic  cleavage  This  has  medium  pleochroism  and  the  formula  jC  = 
blue-green,  b  =  yellow-green,  a  =  yellow:  c>>I»>a.  Titanite  and  appar- 
ently zircon  appear. 

The  analysis  of  this  rock  was  made  by  Mr.  L.  G.  Eakins. 

Analysis  of  amphiholite  from  Worthington. 


SiO,. 

TiOj 

AUOs 

FejOa 

FeO- 

MnO, 

BaO. 

CaO 

MgO 

KsO. 

Na^O 

H2O. 

P2O-,. 


Per  cent 

48.53 

.51 

16.35 

2.03 

10.52 

.17 

trace 

9.83 

9.71 

.32 

1.36 

1.7 

.07 


100. 19 


The  Heath  amphiholite  bed. — Across  Heath  from  north  to  south,  within 
the  border  of  the  Goshen  schist,  runs  a  band,  standing  nearly  vertical  and 


168 


GEOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 


50  rods  wide,  of  a  dull,  dark-gray,  slightly  greenish  amphibolite,  thin-fissile 
and  highly  porphyritic.  It  closely  resembles  the  Guilford  band  in  its  wider 
portion  across  Vermont,  west  of  Brattleboro,  where  the  latter  is  porphyritic. 
The  porphyritic  spots  are  due  to  feldspar,  which  excludes  the  hornblende, 
but  is  itself  full  of  impurities,  especially  biotite.  The  latter  is  wanting  in 
the  main  mass.  It  lies  near  the  western  border  of  the  Goshen  schist  and 
passes  through  the  railroad  cut  east  of  Charlemont  station.  The  upper 
amphibolite  bed  of  the  Hawley  schist  is  at  times  porphyritic,  and  I  have 
assumed  that  this  Heath  bed  was  a  repetition  of  that  upfolded  through  the 
Goshen  schist.  The  small  content  of  lime  and  magnesia  may  be  thought 
to  militate  against  this  assignment  and  indicate  a  relationship  to  the  Guil- 
ford and  Whately  bands,  which  occur  in  the  Goshen  schist  far  to  the  east, 
and  this  is  perhaps  the  best  assignment  of  the  bed. 

An  analysis  of  the  rock  has  been  made  by  Mr.  L.  G.  Eakins,  from  a 
specimen  taken  from  near  W.  M.  Sanford's : 

Analysis  of  Heath  amphibolite. 


The  white  gneiss. — A  single  curious  band  of  white,  thick-bedded  gneiss 
runs  down  through  the  middle  of  the  Hawley  schist  area.  It  passes  through 
the  southwest  corner  of  Halifax,  Vermont,  and  can  be  well  studied  on  the 
high  hill  south  of  the  road.     It  is  a  very  prominent  bed  on  the  road  going 


THE   HAWLEY   SCHIST.  1(59 

u})  to  the  Davis  mine,  where,  u  mile  behi\v  the  mine,  a  crossroad  tnrns  off' 
to  the  east.  It  has  blue  quartz,  single  twinned  feldspars,  and  very  little 
biotite,  and  is  60  feet  thick. 

THE    POSSIBLE    IGNEOUS    ORIGIN    OF    THE    HAWLEY    SCHIST. 

The  theory  that  a  ferromagnesian  formation  like  the  present  may  be 
in  whole  or  part  of  igneous  origin  is  very  attractive,  and  I  know  of  no  sed- 
imentary series  which  could  be  more  easily  transformed  l)y  wholly  intelli- 
gible metamorphic  processes  into  the  present  one  than  the  Triassic  beds  of 
tlie  Holyoke  range,  with  their  interbedded  traps,  tuff's,  and  feiTuginous 
sandstones,  to  which  respectively  the  amphibolites,  chloritic  schists,  and  fas- 
ciculate sericite-scMsts  can  be  compared.  There  remains  now  no  distinc- 
tively eruptive  structure  in 
these  beds.  The  pseudo-por- 
phyritic  character  of  the  am- 
phibolites proves  to  be  caused 
by  the  exclusion  from  the 
white  spots  of  the  black  horn- 
blende needles  by  a  second- 
ary    feldspar      growth,     now 

more      or       less      SaUSSUritic       so         T^g.  9. — Plan  of  altered  dikes  and  quartz  veins  in  clilorite-scbisfc, 


Cliarlemont.     a,  ankerite-chlorite-scliist;  &,  sandy  muacovite-gneiss ; 
that  the   white  feldspar  ground      0,  altered  dikes,  now  green  ankerite-chlorite-scliist;   d,  Mue-quartz 


Teins. 


appears.  A  single  very  strik- 
ing occurrence,  looking  like  a  small  dike  branching  across  the  bedding, 
occurs  in  Charlemont  (fig.  9),  going  up  over  the  bare  rocks  west  of 
A.  P.  Maxwell's  (now  Vincent's),  a  mile  north  of  the  village,  to  the  highest 
rocky  bluff  visible  in  the  woods  from  the  house.  On  the  east  is  the 
common  soft  ankerite-chloi'ite-schist  (a),  and  a  sharp  boundary  line  sepa- 
rates this  from  a  white  feldspathic  muscovite-schist  or  gneiss  of  sandy 
texture  (&)  Distinct  dikes  (c)  of  ankerite-chlorite-scliist  of  slightly  dif- 
ferent texture  from  the  country  rock  (a)  appear  in  the  latter  and  run  out 
into  the  white  gneiss,  branching  and  expanding  into  irregular  forms.  The 
country  rock  is  distinctly  faulted  by  the  dike,  and  a  later  fault  cuts  across 
the  whole  and  throws  it,  and  this  is  filled  with  vein  quartz  (d).  There  is  a 
distinct  foliation  in  the  dike,  which  is  in  part  parallel  to  that  of  the  country 
rock  and  in  part  divergent  therefrom,  as  indicated  in  the  figure. 


170  GEOLOGY  OF  OLD  HAMPSHIRE  COUJirTY,  MASS. 


MINERAL    DEPOSITS. 


THE   PYRITE    BEDS. 


Toward  the  north,  to  some  extent  in  Hawley,  but  more  abundantly 
north  of  the  Deerfield  River,  lenticular  beds  and  impregnations  of  pyrite 
occur,  carrying  a  small  percentage  of  chalcopyrite.  The  success  of  the 
Davis  mine  in  Rowe  has  greatly  stimulated  the  search  for  similar  deposits 
and  their  exploitation.  Much  time  and  money  seem  to  have  been  fruit- 
lessly expended,  and  often  by  those  who  could  ill  afford  it,  without,  so  far 
as  I  could  learn,  consultation  with  any  person  competent  to  advise  upon 
such  matters. 

Many  considerable  beds  have  been  opened,  but  none  have  proved 
remunerative  except  the  Davis  mine,  near  the  east  line  of  Rowe.  This  is  a 
great  lens,  lyiug  with  sericite-schist  as  its  western  (foot)  wall,  and  on  the 
east  chlorite-schist,  which  is  soon  replaced  by  sericite-schist.  The  strike  is 
N.  30°  E.,  the  dip  70°  E.  The  bed  has  been  opened  for  700  feet  on  the 
strike  and  to  a  depth  of  425  feet.  On  the  north  it  swells  in  a  short  dis- 
tance from  6  feet  to  24  feet  and  maintains  this  thickness  nearly  to  the  south 
end.  It  is  an  enormous  mass  of  almost  pure,  coarse-granular,  shining  yel- 
low pyrite,  with  some  chalcopyrite,  blende,  garnets,  and  gahnite — the  two 
latter  fine  and  rare.  I  am  indebted  to  the  proprietor,  Mr.  H.  J.  Davis,  for 
the  facts  concerning  the  workings  of  the  mine  up  to  the  summer  of  1 892. 
It  is  supplied  with  the  most  approved  appliances  of  every  kind.  A  little 
village  has  sprung  up  in  this  desolate  corner  of  a  decaying  town,  and  much 
taste  and  energy  were  manifest  everywhere.  A  new  post-office  (Davis)  has 
been  created,  and  surveys  were  being  made  for  a  narrow-gauge  road  from 
the  mine  to  Charlemont.  Everything  thus  indicates  that  the  mine  is  suc- 
cessful to  a  degree  exceptional  in  the  history  of  mining  in  Massachusetts. 

In  1892  the  greatest  depth  of  No  1  shaft  Avas  601  feet;  greatest  length 
of  adits,  998  feet;  total  depth  of  all  shafts,  621  feet;  whole  length  of  adits, 
5,989  feet;  greatest  width  of  the  vein,  61  feet.  Total  product  of  mine  to 
January  1,  1892,  334,552  tons 

Considerable  work  has  also  been  done  on  Rice's  brook,  a  mile  above 
Charlemont  village,  and  an  engine  has  been  set  up,  but  the  euterj^rise  did 
not  prove  remunerative. 

The  most  abundant  and  promising  deposit  after  the  Davis  mine  is  in 


RHODONITE,  KHODOCHKOSITB,  AND  COTICULE.  171 

tlic  liiji'li  l)liiffs  overlooking  the  road  east  of  M.  V.  Cressy's  "second  pasture," 
w  lic'i-c  t'oi-  ;i  lon^-  distance  along  the  strike,  in  an  area  20  rods  in  width,  the 
chlorite-schist  is  crowded  with  pyrite  in  large,  rougli-faced  cubes  two-thirds 
(if  an  inch  across.    One  layer  nearly  a  foot  thick  has  been  opened. 

COPPER   ORES. 

The  pyrite  beds  usually  carry  a  small  percentage  of  chalcopyrite. 
Copper  is  said  to  have  been  mined  in  a  small  way  northwest  of  M. 
Stetson's  and  northeast  of  P.  Packard's,  in  Plainfield.  In  an  opening  made 
b^•  jM.  V.  Cressy  in  the  pasture  north  of  H.  Baker's,  where  the  sericite- 
schist  is  mucli  impregnated  with  granitic  material,  bornite  is  quite  abun- 
dantly disseminated  in  small  grains,  partly  changed  to  malachite;  and 
farther  north  in  Charlemont,  back  of  the  house  of  G.  Veber,  on  a  blind  road 
running  north  from  the  river  road,  bornite  appears  in  masses  an  inch  across. 

THE  GREAT  HAWLEY  FAUI.T  AND  THE  MAGNETITE  AND  HEMATITE 
DEPOSITS,  THE  RHODONITE  AND  RHODOCHROSITE  BEDS,  AND 
THE    GARNET-SCHIST    OR    COTICULE. 

The  mineral  rhodonite  has  been  found  for  many  years  in  large  bowlders 
in  Cummington,  near  the  Bryant  homestead,  and  it  has,  in  fact,  been  called 
cummingtonite  from  that  circumstance.  Withui  a  year  or  two  state- 
ments have  appeared  in  print  to  the  effect  that  the  ledge  from  which  the 
bowlders  had  been  derived  had  been  found  on  the  Bryant  road  in  Cum- 
mington. On  investigating  the  trenches  I  found  that  they  did  not  reach  any 
ledge  there  at  all,  and  taking  the  direction  of  the  glacial  striae  I  soon  found 
the  ledge  2^  miles  distant  to  the  northwest,  in  Plainfield. 

On  the  road  running  north,  up  the  hill  from  West  Cummington,  at  the 
house  of  T."  Williams,  now  occupied  by  Henry  C.  Packard,  about  35  rods 
south  of  the  house  and  10  rods  west,  a  garnetiferous  sericite-schist  (Savoy 
schist)  on  the  west  abuts  against  the  chlorite-ankerite-schist  on  the  east,  and 
a  band  8  rods  wide  is  filled  with  veins  of  quartz,  quartz  and  magnetite, 
and  quartz  and  rhodonite.  Some  of  the  latter  are  3  feet  wide,  of  the 
finest  and  deepest  color,  often  blackened  at  the  surface.  All  the  varieties 
found  in  the  bowlders  on  the  Bryant  road  in  Cummington  can  be  found  in 
place  here.  The  line  between  the  two  has  the  direction  of  the  glacial  striae 
of  the  region,  and  this  locality  is  doubtless  the  source  of  all  the  Cummington 


172       GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

rhodonite.  Much  mming  was  done  here  in  1848,  but,  it  was  abandoned 
because  of  the  California  gold  excitement.  By  following  the  road  north  a 
mile  and  a  half  to  a  point  where  it  turns  sharp  east,  measuring  60  rods  south 
from  this  bend,  and  going  10  rods  east  into  the  open  field,  one  comes  to 
another  opening  on  a  vein  or  group  of  veins  10  feet  wide,  mostly  quartz- 
rhodonite  veins,  the  unaltered  rock  faintly  pink  and  the  whole  greatly 
blackened  by  oxidation.  These  two  openings  are  called,  locally,  the  man- 
ganese mines.  They  mark  the  line  of  a  great  fault,  which  runs  south 
through  the  area  of  iron-manganese  in  Hawley.  An  inspection  of  the  map 
will  show  that  the  amphibolite  bands  coming  south  are  cut  off  with  an  acute 
angle  against  this  fault,  and  the  contrast  of  the  highly  ferruginous  ankerite- 
chlorite-schists  (Hawley  schist)  on  the  east  and  the  barren  quartzose 
sericite-schists  (Savoy  schist)  is  everywhere  very  striking. 

Across  Forge  Hill,  in  West  Hawley,  this  contact  line  bends  consider- 
ably to  the  east,  but  the  crushed  band,  largely  filled  with  quartz  veins,  more 
or  less  ferruginous,  is  so  wide  here .  that  I  have  represented  the  state  of 
things  by  doubling  the  fault  line  across  this  area.  I  was  guided  the  whole 
length  of  the  iron  deposits  on  Forge  Hill,  south  of  the  old  Hawley  mine, 
by  Mr.  M.  V.  Cressy,  who  owns  most  of  the  land  and  has  examined  the 
country  for  iron  more  carefully  than  anyone  else.  At  the  most  southern 
opening  marked  on  the  map,  and  the  one  where  the  dipping  needle  was  most 
affected,  the  schist  was  impregnated  with  magnetite  for  a  thickness  of  12 
feet  in  the  digging,  and  about  2  feet  of  this  would  j)ass  as  a  lean  ore.  From 
this  point  the  vein  or  veins  can  be  followed  north  for  a  long  distance,  and 
opposite  the  south  end  of  the  amphibolite  band  and  in  the  line  of  the 
straight  fault  marked  on  the  map  considerable  digging  has  been  done  and 
the  magnetite,  here  exceptionally  abundant,  is  accompanied  by  much  flesh- 
colored  quartzite,  apparently  colored  by  rhodonite  and  rhodochrosite.  The 
schist  is  full  of  magnetite  for  many  rods  to  the  east,  and  a  well-marked 
hematite  vein  occurs  here,  with  the  quartz-rhodonite  mixture  accompanying 
it.  About  10  rods  south  of  this  the  epidotic  amphibolite  comes  to  an 
end  and  the  ankerite-chlorite-schist  abuts  against  the  quartz-sericite-schist. 
The  vein  can  be  followed  north  by  disseminated  ore  to  the  Cressy  "second 
pasture,"  a  mile  south  of  the  old  mine.  Here  a  deep  shaft  has  been  sunk 
on  the  vein  at  the  junction  of  the  two  rocks  and  masses  of  pure  magnetite 
were  lying  at  its  mouth,  and  the  accompanying  vein  quartz  here  and  along 


RHODONITE,  RIIODOGHROSITB,  AND  COTICULE.  173 

a  liiu!  a  tew  feet  east  was  pink  from  the  intermixture  of  rhodonite  and 
rhodochrosite.  Ihneuite  and  fluorite  also  occur  here  in  quartz  veins  near  the 
])oint  wliere,  a  few  rods  west  up  the  hillside,  a  new  shaft  has  been  sunk  and 
has  exposed  much  beautiful  corrugated  liematite-schist. 

A  half  mile  farther  north  on  the  vein,  at  Mr.  Cressy's  "first  pasture," 
the  excavations  have  so  exposed  the  vein  as  to  throw  much  light  upon  its 
character  and  origin.  Tlie  following  section  is  exposed,  commencing  on 
the  east: 

Section  in  West  Hawley. 

1.  Dark-green  ankerite-clilorite-schist  (Hawley  schist). 

2.  Compact  vein  quartz,  tinted  iiesli-color  from  rhodonite,  or  rusted  to  deep 
brown  and  black;  vertically  color-banded,  and  with  very  regular  rhombic  jointing, 
3  feet. 

3.  Solid,  rusty,  granular  magnetite,  3-6  inches. 

4.  Granular  quartz  full  of  white  quartz  veins,  carrying  ilmenite,  which  seems  to 
be  the  sericite-schist  crushed,  deprived  of  its  mica,  and  recemented,  18  feet. 

5.  Sericite-schist  full  of  scales  of  hematite  replacing  the  mica  and  fine-granular 
rhodonite,  4  feet. 

6.  Sericite-schist  (Savoy  schist). 

Everything  indicates  the  crushing  of  a  wide  body  of  the  rock  and 
the  deposition  of  magnetite  along  the  main  fissure,  while  manganese  was 
carried  far  out  from  the  fissure  into  the  crushed  rock,  with  much  vein  quartz 
and  ilmenite;  and  still  farther  away  from  the  main  fissure,  and  perhaps 
at  a  lower  temperature,  hematite  replaced  the  mica  of  the  schist. 

The  old  Hawley  mine,  a  half  mile  farther  north,  is  sunk  on  a  vein 
miming  N.  10°  E.  and  dipping  about  80°  E.  This  vein  is  situated  in  the 
sericite-schist,  5  rods  west  of  the  junction  of  this  schist  and  the  ankerite- 
chlorite-schist,  from  whose  abundant  store  of  iron  the  vein  was  doubtless 
filled  when  the  mountain-making  movements  opened  the  fissures  and 
stimulated  the  chemical  activity  of  the  heated  waters.  The  mine  was 
much  worked  many  years  ago,  and  though  the  shaft  was  filled,  the  deep 
open  workings  have  remained  open  and  have  furnished  the  many  elegant 
specimens  of  the  "micaceous  iron"  from  Hawley  found  in  all  cabinets. 

This  is  the  ore  in  the  upper  portion  of  the  veiii,  and  has  been  opened 
for  80  or  90  feet  south  from  the  shaft,  which  is  50  feet  in  depth,  with  a 
maximum  thickness  under  2  feet.  A  cross-cut  of  10  feet  cuts  two  more 
narrow  veins.      It  is  a  well-foliated  rock,  generally  finely  corrugated,  and 


174 


GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS, 


made  up  almost  entirely  of  small,  shining  scales  of  hematite.     1  think  it  is 
a  pseudomorph  after  the  sericite-schist  in  which  it  is  intercalated. 

Below,  the  vein  changes  into  a  firm,  compact  magnetite,  which  is  often 
interlaminated  with  the  quartz-rhodonite  mixture. 
The  mine  has  been  recently  (1891)  opened  by  Mr. 
Ferd.  S.  Ruttmann  with  improved  appliances. 

The  flesh-colored  quartzite,  plainly  colored  by 
manganese,  which  occurs  as  a  veinstone  on  Forge 
Hill  and  south  all  along  the  vein,  has  the  aspect  of 
a  common  granular  quartzite,  but  under  the  micro- 
scope its  appearance  is  very  striking.      The  slide 
looks  exactly  as  if  a  layer  of  half-dried  blood  cor- 
puscles were  spread  upon  it.     They  average  .05""° 
across,  but  vary  from  half  to  double  this  size.   They 
are  flattened  and  circular,  but  not  always  entirely 
regular,  have  darker  centers,  and  are  of  reddish  color. 
They  are'  completely  apolar,  but  have  at  times  a 
polarizing  grain  at  center.     Some  of  them  are  cbm- 
\       plete    trapezohedra,    and    they    are    manganesian 
j       garnets.     A  few  grains  of  quartz  and  a  rare  scale 
\       of  chlorite  complete  the  slide.     This  description  is 
1       of  the  rock  at  Forge  Hill. 

\  From  the  mine  on  Cressy's  land,  on  the  south, 

«  the  arrains  are  much  smaller,  .016™™.  There  is  a 
\  little  more  quartz,  otherwise  they  are  the  same. 
\  The  rock  is  thus  a  coticule  or  quartz-garnet  rock, 
i  tinted  flesh-color  by  manganese,  and  is  a  product 
\  of  the  same  heated  waters  which  have  filled  the 
\       vein  with  hematite. 

^  It  is  at  times  marvelously  contorted,  as  illus- 

trated by  fig  10,  taken  from  a  band  at  the  mine 
on  Forge  Hill.     This  in  appearance  is  a  fine-grained, 
pink  sandstone.     The  folds  are  so  nearly  sheared 
apart  that  a  piece  falls  asunder  easily  in  coarse  bars,  and  the  whole  surface 
is  frosted  over  with  specular  iron.     Few  traces  of  the  iron  can  be  found 
farther  north,  but  south  <rf  the  point  where  the  fault  line  is  made  to  terminate, 


THE  (iOSHEN  ANTICLIISlE.  175 

up  the  steep  hill,  1  have  found,  at  the  abrupt  transition  between  the  chlorite- 
schists  and  the  sericite-scliists,  signs  of  the  continuation  of  the  fault,  in 
tlie  inij)regnation  of  the  rock  with  ferruginuous  quartz  veins. 

An  interesting  vein  occurs  in  the  deep,  picturesque  gorge  below  C. 
Colby's  mill,  near  the  town  house  in  Hawley.  It  is  a  vein,  14  feet  tliick, 
of  (juartz  with  much  hematite  disseminated,  and  tinted  flesh-color  from 
manganese.     There  has  been  some  work  done  here  in  opening  the  vein. 

Another  vein  occurs  here  on  the  hillside  east  of  M.  V  Cressv's  house. 
This  rock  is  impregnated  with  hematite,  and  great  masses  of  interlaced 
epidote  crystals  occur  here.  It  has  been  tested  with  a  diamond  drill  to  the 
depth  of  100  feet. 

On  the  south  face  of  the  high  hill  a  mile  and  a  half  north  of  Charle- 
mont  station  is  a  bed  of  magnetite  6  feet  wide,  which  was  worked  a  little 
over  forty  years  ago.  It  is  for  the  most  part  very  quartzose,  except  1  to  3 
inches  at  the  center,  and  lies  in  the  fasciculite-sericite-schist. 

THE   GOSHElSr  ANTICLINE. 

On  the  line  between  Chesterfield  and  Goshen,  and  stretching  east 
nearly  to  the  center  of  the  latter  town,  is  a  most  interesting  outcrop  of  the 
rocks  of  this  series,  isolated,  and  surrounded  on  all  sides  by  the  newer  forma- 
tion. It  is  a  broad  oval,  with  its  long  axis  parallel  with  the  meridian,  and 
the  beds  are  arranged  as  a  quaquaversal  or  short  anticline,  with  high  dips 
on  the  east  and  low  ones  on  the  west,  and  with  a  fault  crack  along  the  crest 
having  a  considerable  upthrow  on  its  west  side  From  the  friable  nature  of 
the  rocks  this  anticline  is  sunk  by  erosion  into  a  peculiar,  deep,  oval  valley, 
which  separates  the  two  towns  and  in  which  Burnell's  pond  lies  The  area 
is  framed  in  its  whole  circumference  by  a  bed  of  fine-grained,  light-gray 
granitoid  gneiss  about  50  feet  thick,  which  I  have  assigned  to  the  upper 
series. 

Commencing  at  the  north  end  of  the  series,  jiist  west  of  W.  J.  Ball's 
house,  the  rock  is  a  white,  friable,  granular  schist,  containing  a  shining  black 
biotite  on  the  distant  lamination  faces  and  very  large,  scattered  garnets,  and 
varying  from  a  quartz-schist  to  an  almost  quartzless  biotite-schist. 

Farther  west  the  same  biotite-schist  becomes  honiblendic,  like  the 
"fasciculite "-schist,  and  is  replaced  by  a  black  amphibolite.  The  same 
schists  are  continued  down  the  lower  (eastern)  portion  of  the  western  wing 


176  GEOLOGY  OF  OLD  HAMPSHIEE  GOUKTY,  MASS. 

of  the  eroded  anticline.  At  A.,  and  R.  Hawk's  house,  farther  south,  around 
the  south  end  of  Burnell's  pond  and  on  the  east  side  of  the  fault,  the  rock 
is  a  coarse,  light-gray  sericite-schist,  very  micaceous  and  tinged  with  green 
from  the  scales  of  chlorite  mingled  with  the  mica.  This  schist  is  somewhat 
feldspathic,  and  it  carries  subordinate  intercalated  beds  of  gneiss,  bedded 
granite,  and  quartzite.  In  the  upper  portion  of  the  western  side  of  Burnell's 
pond,, and  overlooking  it  as  a  high  bluff,  an  interesting ^bed  stretches  north 
and  south,  which  is  wanting  upon  the  other  side  of  the  fault.  This  is  a 
layer  in  the  sericite-schist  30  feet  thick,  the  upper  part  a  very  coarse,  rusty 
rock,  made  up  of  the  brown  cummingtonite  in  broad,  radiated,  interlaced 
blades  matted  around  deep-red  garnets  1  to  2  inches  across.  There  is  much 
pyrite  disseminated  in  the  rock.  In  its  lower  portion  the  rock  is  made  up 
of  a  ragged  mass  full  of  large  garnets  and  separate  nodules  of  quartz  and 
feldspar,  with  coarse  mica  layers  wrapped  around  them.  This  grades  below 
into  the  gray  sericite-schist,  as  also  above ;  and  in  quartz  veins  in  the  schist, 
immediately  above,  the  finest  cyanite  is  found. 


CHAPTER   VII. 

THE  GRAPHITIC  MICA-SCHIST  SERIES  ON  THE  WEST  SIDE 

OF  THE  VALLEY. 

THE  GOSHEN  SCHISTS  OR  FLAGS. 

The  Goshen  schist  includes  the  lower  portion  of  the  "  calcareomica 
slate"  of  Prof  C.  B.  Adams,  or  the  "calciferous  mica-schist"  of  the  Second 
Vermont  Survey.^  The  second  name  is  objectionable,  because  it  is  used  in 
England  for  a  subdivision  of  the  Carboniferous  and  in  America  for  a  sub- 
division of  the  Silurian;  and  in  the  uncertainty  concerning  the  age  of  the 
beds  here  described  mistakes  have  arisen,  and  it  has  been  supposed  that  the 
name  carried  with  it  an  implication  that  the  rocks  were  Lower  Silurian. 
Moreover,  the  name  as  usually  employed  would  indicate  that  calcite  was 
an  accessory  constituent  of  the  rock,  and  not  that  beds  of  limestone  were 
intercalated  at  wide  distances  in  the  series.  This  latter  is  the  case,  and  in 
central  Massachusetts  they  are  so  widely  separated  that  generally  only  two 
or  three  thin  beds  occur  in  a  township,  and  in  the  lower  subdivision  here  to 
be  described  they  are  almost  wholly  wanting.  The  limestone  grows  far 
more  abundant  northward  across  Vermont. 

GENERAL    DESCRIPTION. 

I  have  taken  as  a  type  for  description  the  broad  band  of  flags  which 
surrounds  the  oval  of  sericite-schist  in  Goshen,  upon  which  all  the  flagstone 
quarries  of  this  town  are  situated.  The  rock  is  a  flat-fissile,  arenaceous 
muscovite-schist,  splitting  quite  regularly  into  flags  2  to  3  inches  thick  and 
of  the  largest  size.  It  is  of  clear  gray  to  rather  dark-gray  color,  from  a 
constant  content  of  graphite.  It  shows  shining  flat  cleavage  surfaces 
pimpled  with  small  garnets  (oo  0).  Staurolite,  cyanite,  and  beds  of  lime- 
stone are  rare  or  wanting. 

'  Geology  of  Vermont,  Vol.  1, 1861,  p.  476. 
MON  XXIX 12  177 


178  GEOLOGY  OF  OLD  HAMP8HIEE  C0U1^[TT,  MASS. 

The  ascending  section  is  (1)  sericite-schist,  (2)  flags,  (3)  corrugated 
schist,  which  is  met  with  in  going  out  on  any  radius  from  the  Groshen  anti- 
chne ;  and  these  three  beds  are  found  exactly  repeated  in  inverse  order  in  the 
west  of  Worthington;  that  is,  on  reaching  the  corrugated  schists  (3),  one 
keeps  on  west  across  them  and  passes  a  synchne,  and  west  of  Worthington 
village  comes  upon  the  flaggy  schists  (2)  exactly  as  in  Goshen,  followed 
farther  westward  by  the  same  hornblendic  sericite-schists  (1).  The  Goshen 
schist  is  here  a  true  flagstone,  splitting  into  thin  slabs  with  smooth  faces.  It 
shows  rarely  staurolites  embedded  on  the  cleavage  faces,  on  which  appear 
also  the  garnets  and  the  cross-sections  of  the  very  elongate  biotite  spangles. 

The  mass  of  the  schist  is  hei'e  a  gray  muscovite-schist,  very  fine-grained, 
in  many  layers  showing  no  free  quartz  when  examined  with  the  lens,  in 
others  showing  much  quartz  in  flattened  lenses  made  up  of  grains  of  white 
quartz,  around  which  the  membranes  of  muscovite  fold.  The  quartzose 
layers  are  2  to  5  inches  thick,  and  alternate  regularly  with  more  mica- 
ceous layers,  so  that  here  cleavage  and  lamination  coincide. 

This  band  is  sharply  ditferentiated  from  the  corrugated  schist  above, 
and  on  the  map  (PL  XXXIV)  the  boundary  is  exactly  laid  down  across 
Worthington  southwardly,  and  except  where  the  till  is  an  obstruction, 
across  Chester  to  the  river.  South  of  this,  as  it  swings  around  the  south 
end  of  the  syncline,  it  is  involved  in  the  general  corrugation  and  can  not 
be  accurately  bounded.  It  has  already  grown  narrow,  and  can  be  clearly 
defined  at  Salmon  Falls,  on  the  Westfield  River,  but  in  the  intermediate 
spaces  the  absence  of  limestone  and  a  less  amount  of  graphite  and  other 
accessories  are  the  only  guide.  Indeed,  the  distinction  is  a  comparatively 
unimportant  one,  but  from  the  great  extent  of  these  graphitic  schists  it  is 
needful  to  search  out  any  recognizable  stratigraphical  distinctions  in  order 
to  unravel  their  structure,  and  to  retain  these  distinctions,  when  otherwise 
unimportant,  in  order  to  express  this  cartographically. 

Northward  from  Worthington  the  flags  widen  across  Cummington  and 
Plainfield.  Northwest  of  Cummington  they  are  finely  developed — an  alter- 
nation of  more  or  less  quartzose  layers  with  intervening  more  micaceous 
and  garnetiferous  layers;  the  latter,  an  inch  wide  and  3  inches  apart, 
preserves  an  original  alternation  of  more  sandy  and  more  clayey  layers. 

The  widening  continues  across  Ashfield.  At  C.  and  B.  Hawes's,  4-inch 
sand  layers,  a  foot  apart,  appear  in  the  dark,  garnetiferous  spangled  schists. 


THE  GOSHEN  SCHISTS  OE  FLAGS.  179 

Across  Hawley  we  find  the  same  lead-gray,  flat  flags,  garnetiferous 
where  micaceous,  biotite-spangled  where  arenaceous,  without  quartz  veins 
and  without  staurolite.  The  hitter  mineral  is  henceforth  absent  as  one  goes 
across  Charlemont  and  Coleraine,  while  otherwise  the  rock  continues 
unchanged. 

UNCONFORMABLE    CONTACT   ON    THE    ROCKS    BELOW.      OUTLIERS    IN    THE 

HAWLEY   SCHIST. 

At  Salmon  Falls  in  Russell,  and  at  E.  Clark's  in  Montgomery,  the 
change  from  the  light  sericite-schists  to  the  graphitic  garnet-bearing  schists 
is  sudden.  In  Chester  the  contact  is  exposed  at  the  falls  high  up  on  a 
branch  of  Sanderson  Brook,  visible  from  the  road  over  the  mountain.  It  is 
just  at  the  north  edge  of  the  Granville  quadrangle.  The  brook  comes 
down  over  the  vertical,  flat,  flaggy  beds  of  the  sericite-schist  from  the 
west;  and  30  feet  above  its  mouth,  at  a  2-foot  granite  dike,  the  change 
is  sudden  to  the  highly  corrugated  black  schists,  very  fine-grained  and 
biotitic,  but  with  little  spangling.  These  schists  effervesce  with  acid, 
and  the  transition  is  abrupt.  A  considerable  unconformity  is  probably 
present,  although  the  black  schists  are  crushed  into  apparent  conformity 
with  the  older  flaggy  schists. 

The  next  place  where  this  contact  can  be  conveniently  studied  is  in 
the  open  valley  of  the  Westfield  River,  1^  miles  southeast  of  Chester,  at 
the  end  of  a  blind  road  which  crosses  the  river  and  railroad  just  west  of  the 
mouth  of  Abbott's  brook.  The  Savoy  schist  is  hornblendic  just  north  of 
E.  Smith's  house,  at  the  end  of  the  road,  then  follows  the  ordinary  sericite- 
schist  on  the  east,  and  the  great  development  of  amphibolite  common  farther 
north  is  wanting  The  junction  begins  just  west  of  and  runs  up  a  small 
gully  in  a  walnut  grove  above  and  northeast  of  the  house  of  E.  Smith. 
There  is  about  3  feet  of  fine  granite  at  the  junction,  and  for  2  rods  east  of 
the  junction  the  Groshen  schist  is  much  corrugated  and  wavy,  and  nearly 
horizontal  bands  of  what  seems  the  original  bedding  run  to  meet  the  vertical 
Savoy  schist.  The  Goshen  schist  is  dark-gray,  garnet-bearing,  and  spangled, 
and  3  rods  east,  across  the  gully,  it  has  the  vertical  posture  and  northerly 
strike  common  to  all  the  region. 

Across  Worthington  the  boundary  is  well  defined  and  is  well  exposed  on 
all  the  roads  leading  down  to  the  Middle  Branch  of  Westfield  River.    Above 


180  GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

the  heavy  bed  of  hornblende-schist  is  a  layer  of  thin-bedded,  soft,  dark, 
crumbly  schist,  made  up  mostly  of  muscovite,  and  almost  wholly  barren, 
showing  rarely  a  large,  shapeless  garnet.  This  is  40  rods  wide,  and  is  per- 
haps best  assigned  to  the  sericite-schist,  though  on  the  map  it  is  colored 
with  the  upper  bed.  The  change  above  is  abrupt  into  the  garnet-  and 
staurolite-bearing  flags. 

The  doubtful  border  layer  mentioned  above  continues  north  across 
Cummington;  and  on  the  road  to  West  Cummington,  south  of  Deer  Hill,  the 
dolomitic  fasciculite-schist  (Hawley  series)  appears  at  L.  Packard's,  with 
amphibolite  on  the  east  of  it,  and  just  east  of  this  amphibolite  is  a  black, 
fine-grained,  graphitic  schist,  pimpled  with  garnets,  which  is  the  base  of  the 
Goshen  schist  and  the  continuation  of  the  doubtful  laver  mentioned  above; 
and  directly  east  of  this  again  is  a  thin  amphibolite  layer,  which  is  a  repeti- 
tion of  the  Hawley  beds,  followed  immediately  by  the  light-gray  Goshen 
flags.     Across  Hawley  and  Plainfield  the  junction  is  nowhere  well  exposed. 

At  the  first  cut  east  of  the  Charlemont  railroad  station  the  same  gra- 
phitic, thin-fissile  slate  occurs  just  above  and  to  the  east  of  the  highest 
hornblendic  bed  of  the  Hawley  schist,  and  is  followed  above  by  the  Goshen 
flags,  with  the  intervention  here  also  of  a  bed  of  amphibolite,  and  this  curious 
boundary  continues  diagonally  across  Heath  from  the  mills  west  of  the 
center  to  the  northeast  corner.  An  important  change  takes  place  here 
which  indicates  the  unconformity  between  the  two  formations.  The  bed  of 
porphyritic  amphibolite  near  the  top  of  the  sericite-schist  is  continuous  clear 
across  the  town  of  Heath,  and  a  little  above  this  the  light-gray,  quartzy 
fasciculite-sericite-schist  (Hawlej^)  comes  in  on  the  east  with  gradually 
increasing  width  and  is  succeeded  a  little  farther  east  by  a  very  plum- 
baginous, friable  slate,  in  which  I  searched  a  long  time  for  fossils.  This 
bed  has  been  dug  for  plumbago  near  J.  D.  Tinkham's,  and  it  is  well 
exposed  at  J.  Loveridge's,  in  the  northeast  corner  of  the  town.  It  grows 
wider  as  it  goes  north,  and  develops  into  well-characterized  Goshen  flags, 
and  is  plainly  an  outlier  of  these  rocks  embedded  in  the  Hawley  schists. 

East  of  this  bed  the  band  of  porphyritic  amphibolite  which  was  men- 
tioned above  in  the  Cummington  and  the  Charlemont  section  widens  and 
becomes  across  the  whole  of  Heath  820  feet  wide.  This  structure  is  well 
brought  out  upon  the  geological  map  and  the  sections  accompanying  it. 
(See  map,  PI.  XXXIV.) 


THE  GOSHEN  SCHISTS  OK  FLAGS.  181 

At  J.  Barber's,  in  Plainfield,  is  another  very  interesting  outlier  of  the 
Goshen  schist.  (See  map,  Ph  XXXIV,  region  west  of  South  Hawley,  and 
section  4  on  PI.  XXIV)  It  is  a  dark-spangled,  garnetiferous  muscovite- 
schist,  and  appears  across  the  brook  south  of  the  house  and  strikes  N.  25°  E 
beneath  the  house  in  a  broad  band.  The  dark  schists  thus  come  in  contact 
with  different  beds  of  tlie  older  rock  as  they  go  north  in  a  way  that  indicates 
the  presence  of  an  unconformity  of  some  consequence,  and  the  relations  of 
these  upper  schists  to  the  Shelburne  anticline  can  best  be  explained  by  the 
assumption  of  an  unconformity  between  them. 

PETROGRAPHICAL  DESCRIPTION. 

Garnetiferous  muscotnte-schist  from  J  Hawke's  quarry,  northwest  of 
Goshen  Center  The  rock  is  a  fine-grained,  even-bedded  schist,  much  used 
for  flagging,  lead-gray  and  arenaceous,  and  is  pimpled  with  garnets  and 
spangled  very  abundantly  by  transversely  placed  scales  of  black  biotite,  as 
is  the  case  with  the  Bernardston  schists  (see  page  291).  The  background 
under  the  microscope  is  a  colorless  mixture  of  quartz  grains  and  muscovite  so 
fresh  and  clear  that  quite  thick  slides  become  transparent  and  the  dark-gray 
color  is  seen  to  be  due  to  the  coaly  grains.  The  garnets  and  the  biotite  are 
much  larger  and  more  abundant  than  in  the  newer  schists. 

The  biotite,  which  has  been  called  adamsite,  phyllite,  and  ottrelite,  but 
which  shows  all  the  optical  properties  of  a  biotite  (meroxene),  is  in  stout, 
thick,  black  crystals,  the  optical  axes  only  slightly  separated,  but  yet  more 
than  in  the  biotite  of  the  newer  schists. 

The  garnets  are  very  curiously  and  regularly  filled  with  quartz  inclu- 
sions of  two  sizes,  arranged  differently,  and  every  crystal  is  the  close 
counterpart  of  every  other.  The  larger  inclusions  have  exactly  the  range 
of  shapes  of  the  fluid  cavities  in  quartz.  They  are  often  rounded,  fre- 
quently having  the  shape  of  a  qixartz  crystal,  and  are  arranged,  closely 
crowded,  in  triangular  planes  resting  upon  the  edges  of  the  dodecahedron 
and  meeting  at  the  center.  They  thus  divide  the  crystal  into  the  twelve 
segments  demanded  by  the  theory  of  the  lower  symmetry  of  garnet,  but 
under  crossed  nicols  every  portion  of  each  crystal  is  perfectly  black  except 
where  the  quartz  inclusions  shine  through. 

The  second  group  of  inclusions  starts  at  the  surface  of  an  ideally  per- 
fect dodecahedron,  an  eighth  of  the  way  in  from  the  siu'face  of  the  crystal. 


182  GEOLOGY  OF  OLD  HAMPSHIEE  COUJ^TY,  MASS. 

leaving  this  outer  band  quite  limpid,  and  extends  about  halfway  toward  the 
center,  the  granules  being  largest  at  the  surface  and  diminishing  regularly 
to  extreme  minuteness  and  arranged  in  lines  normal  to  the  crystal  faces. 
They  are  crowded  so  densely  that  they  give  the  crystal  the  appearance  of 
some  hauyne  or  nosean  sections,  and  by  reflected  light  the  red  of  the  center 
is  gradually  diluted  almost  to  white  at  the  outer  edge,  and  then  framed  by 
the  deep  red  of  the  outer,  clear  border. 

The  quartz  crystals  are  0.15-0.20""  in  size,  the  larger  inclusions 
0.02-0.03""  and  the  smaller  0.01-0.006"".  The  causes  or  forces  which 
brought  out  this  peculiar  structure  must  have  operated  thi'oughout  the  rock 
with  great  uniformity;  must  have  risen  in  intensity  to  a  maximum  and  then 
ceased  suddenly,  and  have  been  followed  by  a  period  when  the  crystals 
increased  without  interpositions  of  quartz.  At  the  last  stage  the  crystals 
were  built  out  only  at  the  edges,  these  being  advanced  in  the  sections  in 
bastions,  often  of  great  regularity.  This  is  figvired  in  Bulletin  No  126, 
under  "Garnet." 

Staurolite  is  a  regular  miscroscopic  ingredient,  often  quite  abundant 
where  it  is  wholly  wanting  macroscopically  It  occurs  in  single  wine- 
yellow  crystals,  not  often  well  formed,  and  is  so  loaded  with  large  elongate 
and  club-shaped  quartz  inclusions  that  three-fourths  of  a  surface  is  often 
occupied  by  the  latter.  Here,  also,  an  outer  band  is  free  therefrom,  though 
not  uniformly  so,  as  in  the  garnet. 

The  biotite,  which  is  usually  quite  pure,  is  of  later  origin  and  includes 
garnet  and  staurolite,  and  has  also  an  outer  clear  border.  There  are  thus 
indications  of  two  times  of  metamorphism.  One  may  perhaps  be  coimected 
with  the  folding  of  the  rocks  and  the  other  with  the  later  intrusion  of  the 
great  granite  masses. 

Biotite-gneiss  from  the  crossroad  to  Buck  Hill,  Blandford;  in  Goshen 
schist.  A  fine-grained,  yellowish  rock,  with  abundant  biotite  scattered  in  a 
sandy  quartz-feldspar  mass. 

Under  the  microscope  the  quartz,  in  grains  coated  with  limonite,  seems 
to  be  clastic.  The  rows  of  pores  do  not  run  from  one  to  the  other,  and  are 
not  parallel.  Rutile  trichites  are  absent.  The  feldspar,  mostly  orthoclase, 
is  in  grains  also  coated  with  limonite,  which  are  at  times  seemingly  increased 
in  size  outside  this  coating.  Rarely  a  grain  of  microcline  or  plagioclase 
appears.  The  biotite,  black  and  fresh,  molds  the  other  constituents.  There 
is  no  trace  of  any  other  constituent,  and  the  rock  is  as  monotonous  under 


THE  GOSHEN  SCHISTS  OE  FLAGS.  183 

tlie  microscope  as  it  is  in  tlie  field,  and  may  be  called  a  bastard  gueiss 
or  a  feldspathic  sandstone  gi-own  biotitic  by  metamorphism. 

Granitoid  hiotite-gneiss  from  neai'  the  great  pegmatite  dike  at  the  south 
end  of  South  street,  Chestei-field ;  fi-om  a  thick  stratum,  conformably  inter- 
bedded  in  the  spangled  mica-schist  near  its  base.  It  bears  a  close  resem- 
bUmce  to  the  Becket  gneiss. 

A  light-gray,  fine-grained,  biotite  granitoid  gneiss,  the  scanty  biotite 
scales  rounded  or  hexagonal,  separate,  and  at  times  deep-red  under  the  lens. 
The  quartz  and  feldspar  are  colorless;  the  latter  is  glassy,  often  showing 
striae.  Under  the  microscope  it  is  remarkably  and  unexpectedly  fresh,  only 
here  and  there  is  a  miTSCovite  growth  accenting  the  twinning  of  a  plagio- 
clase  It  is,  furthermore,  very  unlike  the  Becket  gneiss,  with  which  it 
agrees  macroscopically. 

The  quartz  shows  primary  grains  marked  out  by  iron  rust  and  second- 
ary quartz  in  lobed,  interlocked  masses.  The  abundant  traces  of  water 
pores  generally  contain  globules,  but  these  are  of  small  size  and  only  rarely 
show  motion  They  are  unaffected  by  heat  The  quartz  contains  in  con- 
siderable abundance  the  rutile  (?)  trichites. 

The  orthoclase  is  generally  in  carlsbad  twins,  and  shows  the  most 
remarkable  wavy  extinction.  Microcline  is  well  represented.  The  plagio- 
clase  shows  an  extinction  of  10°  and  4°  on  each  side  the  twinning  plane. 
The  biotite  is  wholly  unlike  that  in  the  Becket  gneiss,  and  resembles 
closely  the  biotite  of  the  mica-schists,  with  which  it  is  associated.  It  is 
bright  brownish-red,  with  strong  dichroism  and  no  tendency  to  change 
into  green  forms  It  shows  parallel  intergrowth  with  muscovite,  and  is 
surrounded  at  times  with  a  band  of  muscovite  scales.     It  incloses  apatite. 

Muscovite  appears  only  microscopically,  and  besides  its  association 
with  biotite  shows  at  times  a  beautiful  microplumose  structure. 

Apatite  occurs  in  great  abundance.  Opaque  iron  ore,  titanite,  rutile, 
and  zircon  are  wholly  wanting. 

THE  COlSrWAY  SCHISTS,  OR  THE  CORRUGATED   MICA-SCHISTS, 

GENERAL  DESCRIPTION. 

This  widely  extended  formation  (the  upper  portion  of  the  calciferous 
mica-schist)  is  a  dark-gray  to  black,  quite  highly  graphitic  muscovite-schist, 
so  sharply  corrugated  that  the  foliation  surfaces  are  often  wholly  lost  in  a 


184       GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

crumpled  ligiiiform  structure.  The  whole  is  often  also  largely  contorted 
and  full  of  white  quartz  veins.  It  is  of  such  fine  g'rain  that  the  separate 
mica  scales  are  just  visible. 

It  is  very  generally  a  "spangled  schist,"  oval  or  elongate  biotite  crys- 
tals being  set  transversely  to  the  bedding,  and  over  considerable  area  all 
parallel  to  a  common  plane,  which  seems  always  to  be  the  plane  normal  to 
the  direction  of  pressure  at  the  time  the  crystals  were  deposited 

Gramet  and  staurolite  are  usually  abundant,  especially  in  the  southern 
half  of  the  area.  In  Cummington  they  become  rare,  and  north  of  this 
town  the  staurolite  disappears  almost  entirely,  coincidently  with  the  disap- 
pearance of  the  great  granite  masses.  There  is  often  an  interlamination  of 
more  and  less  sandy  layers,  and  in  this  case  the  more  sandy  layers  lose  the 
fine  corrugation  described  above,  but  retain  the  spangles  of  transverse  mica. 

Toward  the  east,  where  the  mica-schist  is  entangled  in  the  great  masses 
of  granite  in  Williamsburg  and  Westhampton,  it  largely  loses  the  fine  reg- 
ular corrugation  in  an  extreme  and  irregular  twisting  and  contortion,  and  it 
becomes  of  much  coarser  grain  and  barren  of  all  accessory  minerals  except 
a  few  garnets. 

The  clifiPs  just  south  of  the  locality  for  colored  tourmaline  on  the  old 
Weeks  farm  in  Groshen  (now  Barras  farm)  are  composed  of  a  typical  black, 
coarse,  spangled,  corrugated  muscovite-schist. 

I  have  chosen  Conway  as  the  general  type  of  this  series  because  it  was 
there  first  studied  by  President  Hitchcock,  and  because  it  is  there  most 
calciferous  and  best  shows  the  whole  range  of  variety  of  the  series. 

Through  Russell,  Blandford,  Montgomery,  and  Huntington  gray  cya- 
nite  is  a  common  constituent.  In  the  next  tier  of  towns,  Worthington  and 
Chesterfield,  it  is  not  so  common,  but  occurs  in  finer  specimens  of  rich  blue 
color.  It  is  here  not  so  regularly  disseminated  in  the  rock  as  farther  south, 
but  is  in  veins  of  coarse  quartz,  at  times  associated  with  apatite. 

In  the  same  latitude,  in  Goshen  and  Williamsburg,  zoisite  is  quite  com- 
mon, and  zoisite,  cyanite,  and  staurolite  disappear  from  the  continuation  of 
these  beds  north  across  Franklin  County,  parallel  with  the  increase  in  the 
amount  of  limestone,  though  bowlders  of  zoisite  abound  in  Shelburne. 

As  a  quite  exceptional  occurrence  a  large  area  of  the  schist  on  the  hill 
north  of  Anson  Johnson's  mill,  on  the  Worthington-Chesterfield  line,  and 
not  near  any  granite,  is  full  of  small  black  needles  of  tourmaline. 


TOE  CONWAY  scnisTs.  185 

Across  Franklin  County  the  rock  is  a  rusty,  contorted,  dark-gray  mica- 
schist,  with  few  g-arnets,  rarely  or  never  spangled  with  biotite,  much  twisted 
and  full  of  quartz  veins,  and  abounding  in  black  graphitic  and  biotitic 
limestone  beds,  often  very  impure.  The  ledges  present,  as  a  whole,  a  most 
uninvitingly  ragged  and  dark,  rusty  appearance.  The  rock  is  folded  into 
a  series  of  closely  appressed  folds  in  the  broad  area  over  which  it  extends, 
and  it  is  not  possible  to  unravel  them  and  lay  them  down  separately  upon 
the  map. 

SUBORDINATE   BEDS    IN    THE    CONWAY   SCHIST. 
THE    GNEISS    BEDS. 

There  are  in  several  places  in  the  dark  schists  light-colored  beds  of 
a  fine-grained  gneiss  or  feldspathic  quartzite.  The  transition  from  the  one 
rock  to  the  other  is  very  sharp,  and  in  the  strong  folding  the  rocks  have 
undergone  the  gneissoid  beds  are  found  in  attitudes  relative  to  the  schists 
which  suggest  an  intrusive  origin  of  the  former.  The  small  phenocrysts 
of  feldspar  often  show  twin  striatioii  and  quite  regular  outline,  and  the 
latter  is  true  of  the  quartz  and  the  red-brown  ^mica.  The  groundmass  is  so 
fine  as  to  give  the  whole  the  as^Dect  of  a  trachyte,  but  with  a  strong  lens  it 
is  seen  to  be  sandy  rather  than  felsitic,  and  in  thin  section  it  is  seen  to  be  a 
finely  granular  clastic  mass,  nearly  all  of  small  and  rounded  quartz  grains, 
with  much  clayey  dust,  and  clear  traces  of  the  enlargement  of  quartz  grains 
and  the  later  growth  of  the  small  feldspars  and  mica  scales 

The  most  marked  bed  crosses  the  road  a  few  rods  west  of  the  house  of 
E,  A.  Gates  in  northwest  Leyden,  It  is  13  rods  wide,  runs  a  long  way 
north  and  south  with  the  strike,  is  generally  regularly  intercalated  in  the 
inclosing  schists,  but  in  places  irregularly  thrust  into  them,  and  is  accom- 
panied by  small  parallel  beds,  a  foot  or  less  in  width,  which  seem  like  off- 
shoots of  the  main  bed. 

It  also  occurs  in  Whately,  just  west  of  the  village,  and  near  the  houses 
of  G,  Cowan  (where  the  bed  is  1-2  feet  wide)  and  Mrs.  M.  Taylor,  and  in 
Chesterfield  opposite  the  schoolhouse  on  the  Clark  road. 

There  were  apparently  sudden  transitions  from  the  coaly  clays  to  a 
fine  calcareous  sand,  which  have  allowed  the  development  of  the  small  por- 
phyritic  lime  feldspars  and  only  a  very  small  quantity  of  dark  mica. 


186~  GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 


THE    WHETSTONE-SCHIST. 


This  rock  is  a  fine  but  very  even-  and  sharp-grained,  almost  massive 
sandstone,  with  small  scales  of  a  deep-brown  biotite,  notched  and  in^egular, 
and  often  inclosing  grains  of  the  quartz  scattered  distantly  but  very  regu- 
larly iu  it.  The  biotite  was  of  course  formed  where  it  now  is,  but  the 
quartz  grains  seem  to  be  pretty  purely  clastic. 

It  occurs  in  distinct  beds  in  the  mica-schist,  often  of  considerable 
thickness — 33  to  262  feet.  It  generally  grades  into  the  mica-schist  by 
increase  of  the  size  and  change  in  the  position  of  the  biotite,  and  often  by 
the  appearance  of  garnet  and  staurolite. 

It  occm-s  most  abundantly  in  Chesterfield  and  Worthington,  where  the 
beds  run  for  long  distances  with  the  strike,  and  where  I  spent  much  time  in 
tracing  them  out,  hoping  to  get  useful  material  for  the  study  of  the  struct- 
ure of  the  mica-schist.  I  have  put  them  down  on  the  map  just  as  I  found 
them,  letting  them  end  where  the  outcrop  ends,  and  not  generally  connecting 
fragments  unless  it  vvas  quite  certain  they  were  continuous.  In  many  cases 
one  can  see  on  the  map  that  disconnected  portions  are  probably  continuous. 
In  many  cases  the  common  schists  were  found  after  an  interval  in  exact 
continuation  of  the  whetstone.  In  a  few  cases  this  could  be  proved  to  be 
caused  by  small  faults;  farther  north  in  Franklin  County  and  east  in  the 
granitic  area  these  beds  are  less  distinct  or  wanting,  with  one  notable  excep- 
tion detailed  below. 

The  rock  called  whetstone  in  this  section  is  not,  of  course,  everywhere 
siiitable  for  whetstones,  though  portions  of  the  beds  may  be  of  the  right 
texture  for  this  purpose ;  indeed,  these  beds  have  been  quarried  for  whet- 
stone for  many  years.  Good  quarries  are  found  on  the  south  slopes  of  the 
spodumene  hill  in  Huntington;  the  best  at  B.  Shaw's  in  Cummington. 
They  are  called  Quinnebaug  stones,  and  I  was  interested  to  find  them 
selling  for  50  cents  apiece,  as  the  best  stones  obtainable,  at  a  hardware 
store  in  Brattleboro,  Vermont. 

Ofiicers  of  the  Pike  Manufacturing  Company,  which  owns  quarries  in 
Cummington  and  which  controls  the  manufactm-e  for  a  large  part  of  New 
England,  state  that  the  founder  of  their  business,  Isaac  Pike,  operated  quar- 
ries at  Cummington  about  the  year  1830.  These  quarries  are  not  being 
worked  at  present  (1892),  though  in  the  past  they  have  sometimes  produced 


TUE  CONWAY  SCUISTS,  187 

from  1,000  to  2,000  gross  of  scythe  stones  per  annum.  A  new  quarry, 
which  is  still  worked,  was  ojieued  in  1888  in  Cummington.^  Hitchcock^ 
reports  in  1832  that  mica-slate  is  quan'ied  in  large  quantities  in  Norwich 
(now  Huntington). 

The  most  remarkable  band  of  this  sort  is  encountered  on  the  river  road 
from  Shelburne  to  Greenfield.  The  road  where  it  runs  farthest  south,  in 
Deei-field,  crosses  the  band,  which  is  here  300  feet  wide,  and  its  eastern 
outcrop  is  near  a  small  schoolhouse.  The  next  road  north,  which  enters 
Shelburne  from  the  northwest  corner  of  Deerfield,  crosses  the  same  band 
with  the  same  width,  and  it  seems  to  make  the  whole  flank  of  Arthurs  Seat. 
It  is  a  flat-fissile,  fine-grained,  light-gray,  micaceous  quartzite  with  a  shade 
of  red,  which  changes  on  weathering  to  pale  green,  and  which  recalls  the 
sericite-schist.  East  of  it,  on  the  last-mentioned  road,  is  a  black  garnet- 
bearing  and  biotite-bearing  schist,  exactly  like  the  upper  bed  of  the  Con- 
way schist  at  contact  on  the  Leyden  argillite  farther  north. 

Another  interesting  outcrop  of  the  whetstone-schist  is  the  band  in 
Whately  between  the  great  hornblende  band  and  the  argillite.  This  is  in 
places  somewhat  more  micaceous  and  carries  four  thin  limestone  beds. 
The  same  bed  comes  out  through  the  conglomerate  of  Mount  Toby  at 
Whitmores  Ferry,  in  Sunderland.     (See  page  361.) 

PETKOGKAPHICAL  DESCEIPTIOiSr. 

Opposite  school  on  road  to  Clarke  tourmaline  ledge,  Chesterfield.  Under 
the  microscope  the  whetstone  is  a  mass  of  angular  quartz  grains,  manifestly 
clastic,  with  distant,  regularly  disseminated  flakes  of  biotite  with  irregular 
outlines  conditioned  by  the  surrounding  quartz  grains. 

Pale-green  muscovite  occurs  in  elongate  scales.  There  is  little  coaly 
matter  and  the  magnet  shows  no  magnetite.  A  few  stout  elongated  prisms 
with  cross  cleavage  and  rounded  ends  may  be  andalusite. 

Cummington,  B.  Shaw's  quarry.  Best  quarry  stone.  Like  the  above, 
but  of  darker  color,  finer,  and  more  even  grained.  Under  the  microscope: 
clastic  quartz,  more  biotite,  less  muscovite,  and  much  more  coaly  matter; 
no  magnetite. 

'  L.  S.  Griswold,  Whetstones  and  the  novaculites  of  Arkansas :  Geol.  Survey  of  Arkansas,  1892, 
pp.  24,  73. 

2  Geol.  Mass.,  1832,  p.  23. 


188       GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 


THE    LIMESTONE    BEDS. 


Before  the  introduction  of  railroads  these  beds  of  impure  Hmestone 
were  of  great  importance,  and  they  are  fully  treated  by  President  Hitchcock 
in  all  his  works  on  the  geology  of  the  regionr.  They  are  black,  graphitic 
and  biotitic  limestones,  not  often  above  30  feet  in  thickness.  The  bed  west 
of  Coleraine  village  and  that  in  Whately  are  the  thickest.  They  have  been 
mapped  for  me  with  great  care  by  Mr.  William  Orr,  jr.,  of  Springfield. 

They  increase  in  number  toward  the  north  and  toward  tho  east,  and 
are  most  abundant  in  Ashfield,  Conway,  and  Coleraine,  and  they  continue 
right  up  to  the  Leyden  argillite,  in  which  they  are  wanting. 

In  the  southern  tier  of  towns  occupied  by  these  schists  two  very  nar- 
row beds  appear  in  Montgomery;  in  the  next  tier  to  the  north  none  were 
found.  In  the  next  a  few  unimportant  beds  occur  in  Goshen.  In  the  next 
tier  they  are  abundant  in  Conway,  etc.,  as  detailed  above. 

These  limestone  bands  are  generally  capped  above  and  below  by  a  thin 
layer,  3  to  4  inches  thick,  of  a  black,  compact,  quartz-hornblende  rock,  often 
studded  with  well-formed  black  garnets  (  go  0),  which  are  commonly  called 
melanite,  but  which  aie  a  common  red,  lime-iron  garnet,  colored  black 
by  carbon.  These  bands  have  been  formed  at  the  expense  of  the  lime- 
stone, and  often  one  finds  beds  where  the  limestone  has  been  altered 
entirely;  and  where  a  bed  thms  out  to  6  or  8  inches  it  becomes  wholly 
hornblendic.  The  mica  in  the  limestone  is  arranged  in  mde  spherical 
concretions  of  the  size  of  a  walnut,  and  these  two  structures  explain 
(a)  the  curious  "anvils" — the  columnar  and  mushroom  forms  on  square 
pedestals,  which  are  so  common  in  the  limestone  region — and  (b)  the 
rough,  warty  surface  of  these  peculiar  forms  and  of  the  weathered  lime- 
stone everywhere. 

The  process  of  the  formation  of  these  anvils  is  as  follows  (see  PL 
XXXIII) :  Jointing  separates  a  square  block  of  the  limestone,  with  its  caps 
of  amphibolite.  The  latter  is  more  resistant,  and  weathering  eats  deeply  into 
the  limestone,  forming  anvils,  stools,  or,  where  only  one  band  of  amphibolite 
is  preserved,  columnar  forms,  warty  from  the  projections  of  the  mica  con- 
cretions. They  are  found  most  commonly  in  swampy  places,  where  the 
solution  of  the  limestone  has  been  favored. 

President  Hitchcock  made  many  analyses  of  the  limestone,  which  are 


THE  CONWAY  SCHISTS. 


189 


summarized  below,  excluding-  several  from  bowlders  of  the  Hinsdale  and 

Analyses  of  limestones. 


Stockbridge  limestones : 


Date. 

Locality. 

No.  in  cata- 
losue  of 
State  col- 
lection. 

Sp.  gr. 

CaCoa 

MgSiOi 

SiOa 

FCjOa 

1832.... 
1832.... 
1832.... 
1833.... 
1835.... 
1835.... 
1838.... 
1838.... 

1841.... 

1841.... 
1841.... 

1841.... 
1841 

Whately,  purest 

78.00 
67.00 
58.00 
76  00 
45.00 
63.00 
38.4 

53.8 

66.00 
64.66 

53.80 
64.85 
45.13 

Whately ,  poorest 

Couway  line,  compact. 
Whately 

Southampton 

Williamsburg  bowlder. 
Southampton 

2.93 
2.79 

2.72 

2.72 

2.79 

Norwich,  micaceous 
(gray)  

188 

459 
1916 

2503 
1920 
1921 

Whately,      crystalline 
(gray)  

34.00 
28.79 

46.20 
50.00 
48.57 

Whately 

5.01 

1.54 

Norwich,  micaceous 
(gray)  

Ashfield,  micaceous 

do 

1.60 
3.50 

1.55 

2.70 

THE    AMPHIBOLITE    BEDS. 


THE   CONWAY   BED. 


The  geological  maps  of  Vermont  and  Massachusetts  represent  a  very 
broad  band  of  hornblende-schist  crossing  Guilford,  Vermont,  and  Leyden 
and  Shelburne,  Massachusetts.  This  I  could  not  understand,  as  I  could  find 
only  a  narrow  band  crossing  Shelburne.  Later,  my  assistant,  Mr.  William 
Orr,  jr.,  traced  the  bed  carefully  across  the  Greenfield  quadrangle  and  found 
that  it  widens  in  the  southwest  corner  of  Guilford  so  as  to  cover  a  half  mile  in 
area  and  attains  a  possible  thickness  of  2,000  feet.  It  narrows  rapidly  at 
West  Hollow  Brook,  and  seems  then  to  be  inteiTupted  for  3  miles  to  a  point 
1 J  miles  east  of  Coleraine  Center.  From  this  point  it  is  continuous  south  for 
1 1  miles  to  a  point  a  mile  east  of  Conway.  It  is  best  studied  in  Brimstone 
Hill,  in  Shelburne,  where  it  is  10  rods  wide,  and  a  few  rods  west  of  the 
Conway  railroad  station.  It  is  generally  a  shining  black,  thin-bedded 
rock,  but  at  times  the  content  of  hornblende  lessens  and  the  rock  becomes 
gray.     In  its  continuation  northward  in  Vermont  it  becomes  porphyritic 


190  GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

and  resembles  the  Heath  band  in  the  Goshen  schist.  As  it  crosses  Shelburne 
and  Conway  it  resembles  the  Shelburne  Falls  and  East  Charlemont  band, 
though  lacking  the  abundance  of  pyrite  in  the  latter  (see  PL  VI,  fig.  2). 


THE   WHATBLY  BED. 


The  other  and  more  important  band  of  amphibolite  comes  out  from 
beneath  the  sands  of  the  valley  in  Whately  with  a  width  greater  than  that 
of  the  former  band  at  its  widest,  and  runs  with  increasing  width  southwest 
across  this  town  and  into  Williamsburg,  to  abut  against  the  great  block  of 
granite  in  that  town. 

In  massing  the  evidence  for  the  batholitic  character  of  this  granite  I 
have,  on  page  310,  mentioned  the  series  of  isolated  patches  of  the  schist 
found  for  many  miles  as  inclusions  in  the  granite  along  an  area  extending 
southwest  in  the  line  of  strike  of  the  bed  across  Roberts  and  Sawmill  hills, 
in  the  north  part  of  Northampton,  and  parallel  with  the  similar  inclusions  of 
limestone  and  niica-schist.  Several  of  these  are  marked  on  the  map.  It  is 
very  singular  that  if  the  line  of  this  series  of  inclusions  of  the  hornblende- 
schist  be  continued  south  still  farther  it  would  cross  the  site  of  the  Loud- 
ville  lead  mine.     This  gives  a  curious  interest  to  the  following  extract : 

Serpentine  occurs  at  723  feet  from  the  entrance  of  the  adit  at  Loudville  (South- 
ampton), containing  very  red  quartz  embedded  in  various  directions.  It  is  very  com- 
pact and  .mostly  green.  Here  it  is  but  3  feet  thick.  About  670  feet  is  beautiful  green 
soapstone.i 

There  are,  so  far  as  I  know,  no  specimens  extant  of  the  rocks  men- 
tioned, and  the  adit  has  been  closed  many  years. 

The  fact  that  the  hornblendic  rock  here  discussed  shows  elsewhere  no 
tendency  to  change  to  serpentine  or  talc  lessens  the  probability  that  they 
are  the  same,  and  I  have  been  disposed  to  refer  this  occmTence  to  the  older 
serpentine  connected  with  the  Chester  amphibolite. 

THE   WHITMORBS  FERRY  BED. 

Far  out  in  the  middle  of  the  Triassic  area,  where  the  western  foot  of 
Moimt  Toby  meets  the  Connecticut  River,  is  a  remarkable  outcrop  of 
amphibolite  and  whetstone-schist,  projecting  through  the  Mount  Toby  con- 
glomerate in  a  most  unexpected  way.  The  proofs  of  the  identity  of  the 
amphibolite  with  the  Whately  bed  are  given  in  the  petrographical  descrip- 

1  Amos  Eaton:  Am.  Jour.  Soi.,  Ist  series, Vol.  1, 1818,  p.  137. 


THE  CONWAY  SCHISTS.  191 

tion  following,  und  the  curious  relations'  of  the  bed  to  the  base  of  the 
Triassic  are  discussed  in  Chapter  XII,  under  the  head  of  "The  Mount  Toby- 
conglomerate:" 

PETROGKAPHICAL  DESCRIPTION   OP  LIMESTONE   AND   AMPHIBOLITB.       THE   LIMESTONES.       THE  ANVILS. 
TIIK   PASSAGE   OF   LIMESTONE   INTO   AMPHIBOLITE. 

(a)  Carbonaceous  limestone  from  Whately.  From  the  mass  at  the  bridge 
west  of  the  village,  thrust  up  through  the  argillite  (described  on  p.  196);  a 
dark-gray,  nearly  black,  compact,  traplike  rock,  weathering  deeply  to  a 
red-brown,  porous  and  friable  mass. 

Under  the  microscope  it  is  seen  to  be  a  granular  mixture  of  quartz 
and  calcite,  the  latter  often  multiple-twinned,  and  the  whole  darkened  by 
coaly  matter  in  fine  grains.  In  this  groundmass  are  developed  varying 
quantities  of  muscovite  and  biotite,  the  latter  more  loaded  with  coal  dust 
than  the  general  mass,  indicating  early  crystallization,  when  the  whole 
was  more  coaly. 

(&)  Micaceous  protuberances  on  the  limestone  anvils  from  Goshen  (f).  (See 
PI.  XXXIII.)  This  section  was  cut  from  a  small  warty  protuberance,  an 
inch  across,  from  the  central  limestone  portion  of  an  "anvil,"  which  stands 
in  front  of  the  geological  building  at  Amherst,  to  determine  the  cause  of 
the  regular  projections  on  the  weathered  surfaces  of  the  limestone  portion 
of  the  "anvils."  On  the  fresh  surface  the  projections  appeared  exactly  like 
the  rest  of  the  limestone.  Under  the  microscope  there  proved  to  be  in 
them  considerable  accumulations  of  a  greenish  muscovite,  with  here  and 
there  a  few  scales  of  red  biotite.  The  muscovite  was  filled  with  needles 
of  rutile.  There  was  also  considerable  feebly  pleochroic  hornblende  in 
notched  plates. 

(c)  Base  of  same  anvil.  This  seems  to  have  been  a  passage  bed  from 
the  sandstone  to  the  limestone.  It  is  nearly  4  inches  thick,  and  is  made  up 
of  a  green,  fibrous,  matted  hornblende,  filled  with  quartz  grains  which  are 
in  part  rounded  and  apparently  original,  in  part  turberculous  and  caused  by 
secondary  infiltration,  and  in  part  in  scales  so  sharply  angular  that  they  may 
have  been  crushed  in  place.  Very  many  of  these  quartz  grains  are  crowded 
with  coal  dust  in  the  center  and  are  clear  outside,  indicating  secondary 
enlargement,  and  the  same  is  true  of  the  large  hornblendes.  A  few  much- 
corroded  grains  of  calcite  remain.     There  are  also  grains  and  well-formed 


192  GEOLOGY  OP  OLD  HAMPSHIRE  COUNTY,  MASS. 

crystals  of  titanite,  wine-yellow  and  colorless,  in  considerable  number, 
wliicli  sometimes  contain  grains  of  black  ore,  thick  prisms  of  rutile,  often 
with  dark  border,  rust,  and  a  little  coaly  matter.  The  centers  of  the  horn- 
blende blades  are  often  red-brown,  the  outside  green,  and  they  seem  some- 
times to  be  built  up  around  plates  of  biotite,  but  more  often  the  color  shades 
off  indefinitely  at  the  edges,  and  is  peculiar  to  the  hornblende.  The  horn- 
blende has  weak  pleochroism  x;!>Ir>a;  jc  =  green,  lj  =  olive,  a  =  yellow. 

The  large  white  porphyritic  spots,  2-3"™  across,  are  so  loaded  with 
opaque  white  dust,  muscovite  scales,  etc.,  that  it  is  generally  only  possible 
to  make  out  a  mosaic  of  untwinned  feldspar  and  quartz  grains,  and,  in 
the  absence  of  cleavage  and  twinning,  to  make  sure  that  the  mineral  is  in 
part  biaxial.  In  one  large  grain,  cut  parallel  to  M  (010),  an  optical  axis 
emerged  at  the  lower  left-hand  border,  indicating  anorthite,  and  where 
twinning  occurred  the  extinction  angle  was  very  large,  giving  the  same 
indication. 

(d)  Bim  of  a  similar  ^^  anvil"  from  Plainfield.  (In  the  collection  of 
Amherst  College.  See  PI.  V,  fig.  1,  p.  302,  for  section.)  In  the  matted, 
green,  fibrous  hornblende,  greatly  darkened  by  rust  and  coal  dust,  are 
many  scales  of  a  greenish  mica,  garnets  with  the  same  radial  inclusions  as 
in  the  West  Chesterfield  schist  (p.  182),  curious  long  red  prisms  of  rutile, 
matted  fine  white  needles  with  longitudinal  extinction,  apparently  zoisite, 
and  a  fine  plagioclase,  extinction  26°,  loaded  with  coal  dust,  but  with  clear 
border.  In  other  cases  sections  cut  at  right  angles  to  both  cleavages  gave 
an  extinction  of  38°  to  45°,  indicating  a  very  basic  feldspar 

It  is  significant,  as  connecting  these  beds  with  the  porphyritic  amphibo- 
lites,  that  rounded  clear  spots  of  impure  plagioclase  appear,  from  which  all 
the  dark  constituents  are  excluded. 

The  slides  of  black  hornblende-schist  or  amphibolite  last  described, 
cut  from  the  thin  plates  of  the  rock  which  borders  the  limestone  beds,  and 
which  have  manifestly  been  de^'ived  from  the  limestone,  furnish  abundant 
proof  that  some  amphibolite  beds  may  originate  from  limestone. 

The  thin  beds  of  amphibolite  of  exactly  similar  habit  with  the  above 
and  found  in  the  Conway  schists  have  clearly  the  same  origin,  the  change 
having  reached  the  center  of  the  former  limestone  from  each  side.  These 
beds  have  commonly  a  thickness  of  6  inches  to  1  foot. 

(e)  The  amphibolite  at  the  brook  crossing  in  Whately.     (See  PI.  V,  fig.  3, 


THE  CONWAY  SCHISTS.  193 

p.  302,  for  section.)  The  amphibolite  at  the  brook  crossing  is  thrust  forcibly 
up  tlu'ough  the  ai'gilUte,  together  with  the  black  Conway  limestone,  as 
described  on  page  196.  It  shows  in  many  ways  a  transition  between  the 
uaiTOW  bauds  of  hornblendic  rock  which  form  selvages  to  the  limestone 
beds,  as  described  above,  and  the  larger  bed  which  is  the  subject  of  the 
next  chapter. 

It  is  a  dull,  dark-green,  massive  rock,  which  shows  with  a  lens  the 
usual  interlacing  network  of  actinolite  blades,  with  rare  open  white  spots 
composed  of  a  granular  feldspar,  much  changed  to  mica  The  feldspar  is 
optically  positive  and  has  extinction  +6^°  on  M  (010),  and  so  is  an  oligoclase. 

The  hornblende  is  peculiar  in  two  ways.  It  has  a  brown  center  and 
grades  through  green  to  colorless  at  the  ends  of  the  blades  The  brown, 
is  like  the  cummingtonite  found  in  the  Conway  schists  farther  west.  It 
has  low  absorption  colors.  The  brown  shows  c  =  greenish  brown,  h  =  red- 
brown,  a=  pale  brown;  the  gi-een,  ,c  =  blue-green,  h  =  pale  green,  a  =  pale 
yellow:  c>lj  =  a.  The  blades  are  fibrous  and  often  twinned,  and  give 
extinction  14°  to  17°. 

The  second  peculiarity  of  the  hornblende  blades  is  that  the  brown 
centers  often  show  dark-brown  bands  situated  in  the  basal  parting  and 
sending  out  long,  straight  needles  in  both  directions  parallel  to  the  vertical 
axis,  which  makes  them  look  like  combs  with  teeth  directed  both  ways. 
These  straight  needles  are  also  abundant  everywhere  in  the  hornblende 
and  in  the  feldspars  and  seem  to  be  rutile.  A  "hof"  surrounds  the  larger 
comblike  accumulations  and  dims  their  outline 

Other  hornblendes  are  built  up  around  red  biotites  filled  with  coaly 
matter.  A  few  grains  of  calcite  occur,  and  the  black  ore  grains  show  no 
trace  of  leucoxene. 

This  agrees  so  nearly  with  the  calcite-derived  amphibolite  described 
above  that  one  must  assign  to  it  the  same  origin.  Its  close  association 
with  the  limestone  strengthens  this  conclusion.  It  is,  however,  not  cer- 
tain that  this  bed  is  part  of  the  large  bed  next  described,  though  highly 
probable. 

(/)  The  great  Whately  ampMholite.  This  bed,  which  extends  as  a  broad 
band  across  Whately  and  Williamsburg,  is  for  the  most  part  a  very  fine- 
grained, black,  fissile  rock,  and  in  sections  cut  from  the  north  end  of  the 
bed  the  hornblende  is  present  in  a  network  of  long  blades  with  strong 

MON  XXIX 13 


194  GEOLOGY  OF  OLD  HAMPSHIEB  COUNTY,  MASS. 

absorption  and  pleochroism ;  extinction,  16°  30'.  These  lie  in  a  mosaic  of 
untwinned  feldspar  grains.  Menaccanite  and  leucoxene  are  abundant,  and 
in  slides  from  the  south  end  of  the  bed  in  Williamsburg  (south  of  P.  M. 
Gillett's)  each  grain  of  menaccanite  is  surrounded  by  a  single  crystal  of 
leucoxene,  and  these  often  have  the  regular  wedge-shape  of  titamte. 

East  of  C.  Bardwell's  the  rock  abounds  with  white  spots  which  prove 
to  be  a  quartz-feldspar  mosaic,  greatly  crowded  with  many  impurities,  but 
with  clear  borders.  The  hornblende  is  in  sheafs  and  bundles  of  fine  fibers, 
which  partly  coalesce  into  stout  crystals,  so  that  the  transverse  parting  runs 
across  the  bundle  and  the  center  polarizes  as  a  single  individual.  The  cen- 
tral portion  of  these  large  crystals  is  full  of  coaly  particles.  Pleochroism 
and  absorption  are  weak.  Biotite  and  rarely  a  congeries  of  grains  of 
leucoxene  occur.  This  occurrence  agrees  clearly  with  the  hornblende- 
schist  derived  from  the  calcite  beds  described  above,  and  I  assign  this  origih 
to  all  the  hornblendic  beds  in  the  Conway  schist,  particularly  as  limestone 
is  abundant  and  all  other  traces  of  basic  eruptives  are  wanting. 

All  these  rocks  share  with  the  accompanying  micaceous  schist  the  pecul- 
iarity that  the  centers  of  the  larger  phenocrysts  are  full  of  coaly  matter  or 
fine  quartz  grains,  indicating  that  both  have  together  passed  through  two 
stages  in  the  metamorphic  process. 

This  peculiarity  is  wanting  in  the  similar  amphibolites  of  the  Bernards- 
ton  series  (see  p.  291),  with  which  I  would  compare  these  rocks.  The  latter 
series,  though  of  later  age  geologically,  is  more  metamorphosed  and  differs 
in  the  more  abundant  development  of  the  clear  mosaic  of  untwinned 
plagioclase,  but  in  no  other  way.  They  have  the  same  field  relations, 
the  amphibolite  being  always  interbedded  in  the  schists.  They  have  the 
same  abundant  actinolitic  hornblende,  biotite,  ilmenite  with  leucoxene, 
rutile  with  dark  border,  and  basic  plagioclase,  and  range  from  massive  to 
slaty  varieties. 

At  Mrs.  M.  Taylor's,  in  Whately,  the  rock  is  fine-grained  and  thin-fissile. 
Its  long,  thin  hornblende  needles  have  low  absorption  and  pleochroism,  and 
lie  in  a  feldspar  mosaic.  A  great  number  of  titanite  grains  inclose  one  or 
more  grains  of  black  ore.     For  section,  see  PI.  VI,  fig.  1,  p.  306. 

(^)  The  Whitmores  Ferry  amphibolite.  At  Whitmores  Ferry,  in  North 
Sunderland,  in  the  midst  of  the  Triassic  shales,  arises  an  outcrop  of  a  dark 


THE  CONWAY  SCHISTS.  195 

amphibolite,  easily  mistaken  for  the  bituminous  shale,  and  exactly  resem- 
bling the  above  amphibolite,  especially  in  having  the  highly  refringent 
grains,  each  inclosing  one  or  more  rounded  grains  of  a  dark  ore,  which  is 
here  slightly  brownish.  The  agreement,  macroscopic  and  microscopic,  is 
so  peifect,  and  the  rock  is  chemically  so  nearly  identical  with  the  Guilford 
band  of  amphibolite  in  the  Conway  schist  farther  north,  as  shown  by  the 
analyses  below,  that  one  can  not  doubt  that  the  Whately  amphibolite  is 
continued  in  the  line  of  its  strike  northeast  beneath  the  sandstone  to  the 
Whitmores  Feny  outcrop.-'  The  association  with  whetstone-schist  in  both 
places  strengihens  the  probability  of  their  identity. 

The  agreement  of  the  three  analyses  given  below  is  sufficiently  close 
to  strengthen  the  opinion  maintained  above  that  all  these  hornblendic  rocks 
have  been  derived  from  limestone  beds. 

(li)  The  Guilford  band.  (For  section,  see  PI.  VI,  fig.  2,  p.  306).  An 
inspection  of  the  map  (PI.  XXXIV)  will  show  this  extensive  bed,  beginning 
in  Conway  and  running  continuously  across  the  northern  half  of  the  State 
and  widening  suddenly  as  it  crosses  into  Vermont.  Its  stratigraphical 
relations  do  not  preclude  the  supposition  that  it  may  be  a  great  dike.  Lith- 
ologically  it  is  like  many  beds  of  the  Chester  and  Hawley  series.  Its 
cleavage  surfaces  show  many  black  hornblende  needles  of  high  luster  in 
a  mat  of  finer  needles.  Its  hornblende  crystals  are  not  filled  with  grains 
of  coal  or  earlier  constituents,  as  are  the  other  Conway  beds,  and  also 
the  Bernardston  beds.  The  most  marked  peculiarity  of  this  band  is  the 
presence  in  the  slide  of  many  deep  red-brown  rutiles  clustering  around 
black  ore  grains.  The  feldspar  seems  to  be  albite,  with  which  the  content 
of  soda  agrees. 

ANATYSES  OP  THE  AMPHIBOLITES. 

I.  Gruilford,  Vermont.     Shining-black,  thin-bedded  amphibolite. 

II.  Whitmores  Ferry,  Sunderland.  Outcrop  in  the  midst  of  the  Trias. 
Very  fine-gramed,  dull-black,  shaly  amphibolite. 

III.  Groshen.  Base  of  largest  "anvil,"  from  which  slides  described 
above  (p.  191)  were  taken.  A  quartz-hornblende  rock,  formed  by  the  alter- 
ation of  the  limestone  by  reaction  of  solutions  derived  from  the  inclosing 
schists.     For  general  discussion  of  analyses  see  page  300. 

1  See  p.  361. 


196 


GEOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 
Analyses  of  the  amphiboUtes,  by  L.  G.  Eahins. 


SiOj 

TiO, 

AI2O, 

Cr.O, 

Fe^Oj 

FeO- 

MnO 

BaO 

CaO. 

MgO 

K,0. 

Na.O 

H2O. 

PsOs 


49.16 

1.03 

16.43 

trace 

3.92 

7.19 

.23 

.02 

9.21 

8.19 

.41 

3.70 

.45 

.16 


II. 


49.86 

1.58 

15.50 


100. 10 


2.99 
8.01 

.07 

trace 

8.89 

7.79 

.72 
3.26 
1.51 

.11 


III. 


55.64 

.50 

16.27 


1.22 

7.20 

.28 


100. 29 


9.23 

5.58 

.19 

.91 

3.11 

.23 


100.36 


PROJECTION    OF    THE    LIMESTONE    AND    AMPHIBOLITE    OF    THE    COKWAY   SCHIST 
THROUGH   THE    LEYDEN   ARGILLITE    IN   WHATELY. 

Following  the  road  west  from  the  hotel  in  "Whately,  one  comes  in  a 
few  steps  upon  a  bridge  over  a  small  brook,  and  to  the  north  across  the 
brook  a  fresh  sui-face  has  been  exposed  in  the  bluff  by  blasting.  An  inspec- 
tion of  the  wall  reveals  small  spots  of  pyrite  as  the  probable  cause  of  the 
blasting,  and,  what  is  of  greater  interest,  one  soon  finds  that  a  small  boss 
of  the  black  limestone  and  the  amphibolite  of  the  Conway  series,  both  of 
which  are  in  place  a  considerable  distance  to  the  west,  has  been  here 
thrust  up  through  the  argillite  with  great  force.  The  argillite  dips  away 
from  the  limestone  on  both  sides  and  mantles  round  its  end,  as  shown  in 
fig.  11. 

A  few  rods  up  the  brook,  on  the  other  side  of  the  road,  several  similar 
bucklings  of  the  limestone  and  hornblende  rock  up  through  the  argillite 
may  be  seen.  This  shows,  of  course,  that  the  Conway  mica-schists  are 
carried  far  beneath  the  argillite  and  thus  are  older  than  it.  The  amphib- 
olite and  the  limestone  are  identical  with  those  farther  west  in  the  Conway 
schist  and  are  described  above.  As  an  indication  of  the  force  with  which 
the  limestone  was  thrust  up   through  the   newer  rock,   there  follows  a 


THE  CONWAY  SCHISTS. 


197 


desci-iption  of  a  vein  of  hard,  vitreous  quartz  7  inches  iu  width,  which  ruus 
across  the  face  of  the  limestone;  it  is  represented  in  fig.  12,  p.  198. 

The  laro-e  vein  is  twisted  and  the  limestone  is  kneaded  into  the  com- 
pact quartz  and  drawn  out  into  long  filaments  carried  down  into  the  center 
of  the  vein  and  pinched  oft'  in  it,  and  the  smaller  veins  are  contorted  still 
more  remarkably.  The  limestone 
has  received  a  marked  fluidal 
stracture  in  the  apophyses,  which 
penetrate  the  quartz  throughout 
its  whole  mass  in  curving  bands, 
which  fit  themselves  with  more  or 
less  success  to  the  complex  surface 
of  the  vein.  Under  the  micro- 
scope the  limestone  shows  all 
stages  in  the  development  of  a 
cleavage  by  slipping  caused  by  the 
pressure  (Ausweichungsclivage  of 
Heim.^) .  Portions  of  a  thin  section 
cut  at  right  angles  to  the  cleavage 
plane  break  up  into  a  series  of  very 
long,  thin  wedges,  placed  with  their 
cutting  edges  pointing  alternately 
in  opposite  directions.  Each  wedge 

shows  a  fluidal  structure,  expressed     Fio-  H— Map  showing  tlie  protrusion  of  the  limestone  of  the 

Conway  schist  through  the  Leyilen  argillite.    "Whately. 

by  the  bending  of  the  lines  of  coal 

particles  toward  its  head.  This  slipping  of  the  wedges  alternately  to  right 
and  left  concentrates  the  coaly  particles  somewhat  along  the  boundaries  of 
the  wedges,  by  which  they  themselves  become  more  distinctly  defined,  and 
at  last  confluent  into  a  new  plane,  marked  at  once  by  a  cleavage  and  a 
color  banding. 

CONTACT   METAMOEPHISM    OF   THE    LIMESTONE    BY   GRANITITE.      ARGENTINE. 

A  very  interesting  exposure  occurs  on  the  river  road  from  Leeds 
to  Haydenville,  near  the  junction  of  the  biotite-granite  (granitite)  and 
the  muscovite-granite.      The  former  is  very  confusedly  melted  into  the 


Arg////fe. 
Hornblende  Schist 


Limestone. 
Covered. 


'Untersuchungen  uber  den  Medianismus  der  Gebirgsbildung,  Basel,  1878. 


198 


GEOLOGY  OP  OLD  HAMPSHIRE  COUNTY,  MASS. 


remnants  of  mica-schist  which  occur  as  inclusions  in  the  great  granite 
mass,  and  at  one  point  appears  a  grayish-white,  massive,  fine-grained  rock 
which  proves  under  the  microscope  to  be  a  labradorite-pyroxene-calcite 
rock.  Treated  with  acid,  it  leaves  a  glassy,  friable  mass,  in  which  scales  of 
graphite  and  needles  of  bright-green  actinolite  are  visible. 

Under   the    microscope  it  shows  an    abundance  of   calcite,  multiple 
twinned;  labradorite,  extinction  14°,  often  doubly  twinned;  and  large  color- 


I"IQ.  12.— Surface  of  black  limestone  with  contorted  quartz  veins.    Whately.    Scale,  ^. 

less  pieces  of  pyroxene,  extinction  41°,  inclosing  many  grains  of  the  other 
constituents.  Rounded  grains  of  titanite  occur.  This  may  be  referred  to 
the  graphitic  limestone  of  the  Conway  mica-schist  altered  by  the  granite,  and 
this,  in  connection  with  the  long  distance  across  the  granite  area  that  one 
can  follow  the  hornblende-schist  (see  p  190),  leads  one  to  conclude  that  the 
mica-schist  fragments  in  the  granitic  area  in  Williamsburg  are  also  remnants 
of  the  Conway  schist,  and  that  the  "argentine"  occurrence  in  the  midst  of 


TUE  CONWAY  SCHISTS.  199 

the  granite  still  farther  south,  on  the  Westhampton  Hue,  is  another  remnant 
of  the  same  limestone  from  the  Conway  schist  which  formerly  mantled  over 
the  grauite.^     The  inclusion  is  still  partly  micaceous  limestone. 

CLEAVAGE  IN  THE  CONWAY  SCHISTS. 

In  the  flags,  or  Goshen  schists,  the  original  lamination  seems  to  be  gen- 
erally preserved.  In  the  Conway  schists  a  distinction  can  be  made  between 
the  eastern  half  of  the  schists  in  the  granitic  area,  where  the  impregnation 
of  granite  and  quartz  and  the  great  contortion  leave  one  at  times  in  doubt 
as  to  the  origin  of  the  foliated  structure,  and  the  western  or  lower  portion, 
where  the  fine  crenulation  or  corrugation  produces  a  ligniform  structure  in 
which  strike  remains  distinct  but  dip  becomes  quite  uncertain. 

Without  searching  far  one  can  generally  find  a  banding  of  coarser  and 
finer  material — a  bed  of  limestone  or  whetstone-schist — and  then  generally 
will  find  the  foliation  to  agree  with  the  original  lamination.  This  is  beau- 
tifully seen  at  the  dam  in  Huntington  village.  Standing  at  a  distance,  the 
laminae,  from  2  to  14  inches  in  width  (average  6  inches),  are  each  bounded 
by  a  black  band  at  the  bottom,  2  to  3  inches  wide,  which  shades  off"  above 
into  the  lighter  portion,  the  whole  making  exactly  the  impression  of  a  lam- 
inated sandstone,  the  lower  part  of  each  being  fine-grained  and  clayey,  the 
upper  part  coarse  and  sandy.  On  inspection  the  lower  portion  is  found 
to  be  dark  from  the  abundance  of  garnet,  biotite,  staurolite,  and  cyanite, 
while  the  light  portion  is  sandy  and  contains  only  scattered  garnets. 

What  seemed  at  a  distance  to  be  true  was  doubtless  once  true,  and  the 
lower  portion  of  each  layer,  being  argillaceous,  has  given  rise  to  the  alumi- 
nous minerals  wanting  in  the  sandy  portion  of  the  layer.  A  part  of  the 
dark  color  also  depends  upon  the  fact  that  the  new-formed  minerals  have 
often  inclosed  much  coaly  matter  that  might  otherwise  have  been  carried  off. 

At  other  places  precisely  the  same  structure  enables  one  to  detect  a 
well-developed  cleavage.  This  is  the  case  along  the  western  of  the  two 
roads  going  south  from  Chesterfield  Center,  and  on  the  east-west  road  a 
mile  south  of  the  village. 

This  is  finely  illustrated  also  along  the  east  side  of  the  road  going  south 
from  Stevens's  mills,  in  Worthington,  in  a  field  abounding  in  most  beau- 
tiful roches  moutonndes.     The  rock  is  a  dark,  corrugated  mica-schist.     The 

'  See  "Argentine"  in  Mineralogioal  Lexicon :  Bull.  U.  S.  Geol.  Survey  No.  126,  1895,  p.  43. 


200  GEOLOGY  OP  OLD  HAMPSHIEE  COUNTY,  MASS. 

lamination  is  marked  by  alternations  in  color,  in  bands  1  to  6  inches 
tliick,  exactly  as  described  above.  A  dike  of  tourmaline-granite  coincides 
in  position  with  this  structure ;  strike  N.,  dip  70°-80°  E. 

The  cleavage  is  indicated  by  a  bedding  which  comes  out  by  weather- 
ing, and  along  which  alone  the  rock  splits  easily,  and  membranes  of  mica 
are  developed.  This  strikes  N.  40°  E.  and  dips  25°-30  W.  There  is  in 
this  last  structure  a  cleavage  changing  into  a  foliation. 

In  general  cleavage  is  subordinate  in  these  schists,  and  usually  where 
it  occurs  the  strike  of  the  primary  and  secondary  structures  very  nearly 
coincide. 

FOSSILS  (?)  OF  THE  CONWAY  SCHISTS. 

In  many  places  cavities  coated  with  rust  are  found  in  the  quartzose  and 
slightly  calciferous  beds  in  the  schists,  which  I  have  no  doubt  represent 
fossils,  but  which,  in  every  case  that  has  come  to  my  knowledge,  are  so 
poorly  preserved  that  it  is  possible  to  explain  them  as  due  to  the  removal 
by  solution  of  some  mineral,  possibly  calcite.  The  mode  of  occurrence 
suggests,  however,  that  a  large  number  of  small,  flat  bivalve  shells,  5-25°"" 
long,  were  deposited,  all  lying  flatwise  and  about  equidistant  in  the  sands 
which  have  now  become  the  whetstone-schists.  In  a  bowlder  found  on 
the  railroad  in  Worthington  these  cavities  were  flattened,  nearly  round, 
5-7°""  long. 

West  of  E.  B.  Drake's,  in  the  northwest  part  of  Chesterfield,  the  cavities 
are  about  15-25™"  long,  flattened  oval,  and  in  many  cases  two  such  impres- 
sions lie  side  by  side  joined  by  a  straight  line,  strongly  suggesting  the  opened 
valves  of  a  leperditia  like  L.  haltica.  They  are  flat,  rust-covered  cavities, 
and  in  one  fresher  part  of  the  rock  are  represented  by  darker  spots,  all 
arranged  parallel  to  the  bedding  plane  of  the  rock,  and  having  the  same 
shape  as  the  cavities.  These  dark-gray  spots  seem  to  be  only  spots  in  the 
sandstone.  They  effervesce  much  more  abundantly  than  the  rest  of  the 
rock,  and  seem  to  be  flattened  concretionary  patches  of  a  calcite  darkened 
by  carbon. 

At  the  Clarke  tourmaline  ledge  an  exactly  similar  occurrence  is  found, 
only  the  cavities  are  a  little  larger. 

At  B.  Shaw's  whetstone  quarry,  in  Cummington,  is  a  bed  of  the  whet- 
stone about  IS"""  thick,  full  of  closely  approximated  tubular  cavities  2-3"" 


THE  LEYDEN  ARGILLITB.  201 

in  diameter  and  parallel,  which  suggest  scolithus,  but  which  are  parallel  to 
the  bedding. 

All  these  specimens  were  submitted  to  Mr.  C.  D.  Walcott  and  other 
paleontologists,  but  they  could  not  decide  that  any  of  them  were  certainly 
ot"  organic  origin. 

THE  LEYDEN  ARGILLITE. 

DESCRIPTION. 

The  rock  is  in  its  whole  extent  of  uniform  texture  and  structure — a 
dark-gray  and  very  fine-grained  slate  with  glistening  cleavage  surfaces, 
dull-black  when  broken  across  the  ends,  and  generally  crumpled  and  corru- 
gated to  the  extreme  of  complexity.  It  is  remai-kably  barren  of  all  acces- 
sory minerals,  and  this  has  been  taken  as  a  characteristic  to  distinguish  it 
from  the  Conway  schists,  though  in  places  small  garnets  and  biotite  scales 
are  scattered  sparingly  over  its  cleavage  surfaces.  Slaty  cleavage  is  devel- 
oped in  it  in  every  degree.  Thin  sandy  layers  often  show  the  original 
bedding  after  the  rock  has  been  crumpled  up  into  shai-p  folds  and  the 
cleavage  perfectly  developed  outside  these  layers,  and  the  rock  can  still  be 
separated  along  these  into  thick  plates  fluted  and  folded  in  the  sharpest 
curves,  and  at  the  ends  of  the  plates  the  slaty  cleavage  is  seen  to  cut  across 
the  slab  and  to  divide  it  into  thin,  flat  laminae  regardless  of  its  convolutions. 
Moreover,  the  importance  of  the  shearing  force  in  the  development  of  cleav- 
age can  often  be  beautifully  seen,  the  fine,  close-set  and  equidistant  corru- 
gations becoming  sharper  and  changing  from  folds  into  faults,  and  the 
elements  between  these  faults  being  flattened  out,  with  some  degree  of  flow 
of  the  material,  into  the  cleavage  plates. 

A  remarkable  block  found  (not  in  place)  at  the  outcrop  nearest  and  to 
the  west  of  the  lower  quartzite  of  the  Williams  farm  in  Bernardston  may 
find  mention  here.  A  mass  of  chlorite-slate  3  inches  wide  cuts  across  the 
argillite  exactly  like  a  dike.  It  is  bounded  by  parallel  planes  and  is  sharply 
demarcated  from  the  argillite,  and  while  both  are  cleaved  perfectly  at  right 
angles  to  the  plane  of  the  dike,  the  plane  of  cleavage  in  the  green  schist 
makes  a  small  angle  with  that  of  the  argillite.  One  can  not  well  avoid 
surmising  that  a  small  diabase  dike  has  been  here  very  curiously  metamor- 
phosed, but  the  microscope  shows  only  matted  chlorite  and  muscovite  scales, 
quartz,  and  geniculate  rutiles,  the  latter  visible  also  with  the  lens. 


202       GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

The  argillite  is  characterized  by  a  great  abundance  of  quartz  nodules 
and  bosses,  often  of  great  size,  which,  though  not  wanting  in  the  Bernards- 
ton  series,  are  there  comparatively  unimportant. 

On  the  road  from  Greenfield  to  Charlemont,  above  Fall  River  bridge, 
the  argillite  is  a  fine-cleaved  roofing  slate  for  a  long  distance  by  the  road- 
side, almost  as  fine  a  slate  as  that  at  the  Gruilford  quarries  in  the  town  next 
north  in  Vennont. 

QUARTZITE    IN   THE   AE6ILLITE. 

On  the  road  north  from  Bernardston,  at  C.  Cushmore's,  is  a  heavy 
layer  of  a  dark,  thick-bedded  quartzite  about  33  feet  thick,  and  a  little  far- 
ther north,  at  I.  K.  Brown's,  is  a  crumpled,  thin-bedded  quartzite. 

Just  over  the  State  line  to  the  north,  near  the  Guilford  slate  quarries, 
the  argillite  is  replaced  by  a  fine-grained  quartzite,  which  President  Hitch- 
cock called  a  novaculite-schist  and  found  to  be  a  quarter  of  a  mile  thick.^ 

PETROGRAPHICAL   DESCRIPTION. 

The  mass  of  rock  is  made  up  of  minute,  elongate,  brightly  polarizing 
muscovite  microlites,  often  raveled  out  at  the  ends  and  with  wavy  sides,  in 
an  amorphous  background.  Clay-slate  needles  are  only  doubtfully  present. 
Stout  elongate  forms,  opaque  by  transmitted  and  curdled  white  by  reflected 
Kght,  seem  to  be  leucoxene  derived  from  menaccanite.  Magnetite  and 
calcite  are  wanting.  There  is  much  coaly  matter  in  swarms  of  black 
dots,  and  rarel}^  a  biotite  scale  placed  in  the  plane  of  cleavage.  Often  a 
strongly  marked  pseudo-fluidal  structure,  expressed  by  the  position  of  the 
elongate  muscovite  crystals,  indicates  clearly  the  mode  in  which  pressure 
has  produced  this  cleavage. 

Microscopically  the  rock  is  thus  a  very  fine-grained,  argillitic  mica- 
schist  or  phyllite,  and  it  differs  much  from  the  true  argillites,  e.  g.,  the 
cleaved  slates  of  Snow  den,  Wales,  or  the  slates  of  Hoosick  Falls,  New 
York,  with  which  I  have  compared  it.  I  have  followed  custom  in  applying 
the  name  argillite  to  the  band  of  rock,  somewhat  in  a  geological  sense. 

The  rock  sometimes  contains  small  garnets  in  considerable  number,  and 
these  are  often  changed  wholly  or  partly  into  small  white  balls  of  kaolin, 
or  kaolin  and  hematite.     The  kaolin  was  infusible  and  gave  blue  color  with 

1  Vermont  Report,  Vol.  I,  1861,  p.  490. 


THE  LEYDEN  ARCilLLITE.  203 

cobalt,  and  no  reaction  for  potash.     The  mass  of  kaolin  does  not  quite  fill 
the  cavities.     These  occur  north  of  the  Devonian  limestone  in  Bernardston. 

STRATIGRAPHY. 

The  rock  is  crushed  into  sharp  folds  and  finely  coiTugated,  and  where 
sandy  layers  are  wanting  the  primary  structure  may  be  replaced  wholly 
by  the  cleavage;  in  other  places  it  is  brecciated  and  thrown  into  con- 
fusion. Everywhere  the  strike  and  dip  vary  suddenly  and  within 
wide  limits.  About  N.  20°  E.  may  be  the  average  strike,  and  60°  E.  the 
average  dip. 

A  comparison  of  hand  specimens,  and  especially  of  sections  of  the 
three  rocks,  shows  that  the  "argillite,"  while  a  distinct  mica-schist,  is  far 
less  thoroughly  metamorphosed  than  the  schists  in  the  Helderberg  series, 
and  from  this  criterion  alone  one  would  consider  it  the  newest  rock  in  the 
whole  ai'ea.  That  it  is  newer  than  the  mica-schists  to  the  west  and  older 
than  the  Helderberg  series  seems  to  me  in  the  highest  degree  probable,  and 
also  that  the  two  older  groups  are  Paleozoic;  but  I  can  find  no  very  con- 
vincing ground  for  their  assignment  to  a  definite  horizon  in  the  Paleozoic. 

BOUNDARY   ON   THE    CONWAY    SCHISTS. 

At  Beaver  Meadow,  in  the  northeast  corner  of  Leyden,  one  finds  the 
point  of  contact  just  at  the  foot  of  the  mill  dam.  The  black,  baiTen  argil- 
lite  has  strike  north  to  south,  dip  70°-80°  E.,  all  the  way  up  from  Fall 
River,  a  mile  east,  and  often  shows  true  cleavage.  Here  several  thin, 
rusty  beds  appear,  and  quite  suddenly  the  rock  becomes  slightly  coarser 
and  full  of  very  small  spangles  and  transverse  crystals  of  biotite ;  and  three 
thin  beds  of  black  limestone  occur  in  quick  succession.  The  boundary  is 
best  drawn  at  the  first  bed  of  limestone,  just  at  the  dam,  but  for  300  feet 
below  the  rock  is  black,  fine-grained,  finely  double-corrugated,  and  difi'ers 
mainly  in  the  minute  mica  spangling  from  the  argillite  lower  down  the 
brook,  and  for  a  little  way  above  this  limestone  much  of  the  rock  can 
scarcely  be  distinguished  from  the  argillite.  It  is,  however,  a  little  coarser, 
rusty  on  cleavage  faces,  and  spangled  on  transverse  fractures.  It  is  thus  a 
rather  gradual  transition,  and  President  Hitchcock  was  often  in  dotibt 
about  the  existence  of  any  boundary  whatever. 

Exactly  the  same  transition  occurs  between  the  two  beds  at  all  places 


204  GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

where  the  boundary  can  be  studied.  At  the  base  of  the  argilUte  one  finds 
minute  spangles  of  mica;  a  few  feet  below  comes  limestone,  and  then  the 
rock  quickly  grows  coarser,  mica-spangled,  and  garnetiferous.  This  is  well 
seen  toward  the  south  end  of  the  boundary  line,  in  the  southeast  corner  of 
Coleraine,  near  the  house  of  D.  Nelson. 

In  the  Whately  area  the  transition  is  almost  exactly  the  same,  but  a 
heavy  band  of  white  quartz  marks  for  a  long  distance  the  exact  boundary, 
and  there  is  probably  a  fault  there.  I  have  found  nothing  along  this  bound- 
ary which  would  suggest  the  existence  of  unconformity  between  the  two 
beds. 

argillite  in  the  western  boeder  of  the  "graphitic  mica-schist " 

(goshen  schist). 

An  inspection  of  the  map  of  the  Vermont  survey  of  1861  shows  a  broad 
band  of  argillite,  bordered  on  the  west  by  Devonian  limestone,  extending 
south  from  Lake  Memphremagog,  and  thinning  south  and  disappearing 
midway  the  State. 

Along  the  west  border  of  the  Groshen  schists,  where  they  enter  Massa- 
chusetts, in  Heath,  is  a  band  of  thin,  black  slate  that  looks  exactly  like  the 
metamorphosed  Carboniferous  slate  from  Worcester,  and  which  seems  to  be 
the  continuation  of  the  Memphremagog  slate.  Farther  south  it  is  indistin- 
guishable from  the  ordinary  Goshen  schists,  except  across  Worthington, 
where  a  band,  50  rods  wide  at  the  base  of  the  schists,  is  a  fine-grained, 
barren,  flat-fissile  schist,  unlike  the  garnetiferous  schist  above  and  the  horn- 
blende-schist below.  These  beds  are  described  in  some  detail  in  following 
down  the  western  border  of  the  Groshen  schist  (see  page  179).  I  have 
treated  them  as  the  base  of  the  Goshen  schists,  and  think  this  the  most 
probable  view.  There  is  no  satisfactory  reason  for  identifying  the  two 
argillites.  The  western  seems  inconstant,  and  does  not  appear  in  the  Goshen 
anticline. 

relative    age    op   the    CONWAY    SCHIST    AND   THE    LEYDEN   ARGILLITE. 

An  examination  of  the  comparative  sections  on  page  258  will  show 
that  the  first  discrepancy  of  importance  there  indicated  is  in  regard  to  the 
relative  positions  of  these  two  series,  the  argillite  being  regarded  as  the 
lower  and  assigned  to  the  Huronian  by  Professor  Hitchcock. 


THE  LEYDEN  ARGILLITE.  205 

The  Leyden  argillite,  as  it  runs  north  through  Vermont,  borders  and 
everywhere  rests  upon  the  Conway  schist,  where  they  are  not  vertical.^  In 
the  discussion  of"  the  argilHte  in  the  Vermont  survey  it  is  placed,  without 
hesitation,  above  the  schist;  indeed,  is  still  associated  with  the  limestone  and 
assigned  to  the  Devonian.^  In  the  Geology  of  New  Hampshire,  Professor 
Hitchcock  has  shown  that  the  "calciferous  mica-schist"  dips  beneath  the 
argillite  clear  across  the  State. 

The  much  more  pronounced  metamorphism  of  the  schists,  the  abun- 
dance of  great  granite  veins  containing  rare  minerals,  as  well  as  the  long 
series  of  minerals  found  in  the  schists  themselves,  may  be  contrasted  with 
the  baiTenness  and  low  degree  of  metamorphism  of  the  argillite  as  indicat- 
ing that  the  schist  is  the  older  rock.  The  microscopic  description  of  the 
two  rocks  may  be  compared  from  this  point  of  view. 

The  locality  at  the  brook  west  of  Whately  village  (see  page  196)  is 
also  a  decisive  one  in  reference  to  the  question  of  the  relations  of  the  two 
rocks  under  consideration.  That  the  triangular  area  of  argillite  occurring 
here  is  a  continuation  of  that  in  the  Bernardston  area  is  quite  certain,  in 
view  of  their  complete  identity,  and  has  not  been  doubted  by  anyone;  and 
that  the  black  limestone,  with  its  border  of  hornblende  rock,  is  the  common 
limestone  of  the  lower  formation  is  eqiially  clear;  but  the  latter  is  here 
tlu'ust  up  through  the  argillite  in  a  knob,  like  a  button  thi'ough  a  button- 
hole, and  the  argillite  mantles  around  it  and  dips  away  from  it  on  all  sides, 
and  this  is  far  out  in  the  middle  of  the  argillite,  showing  that  the  latter  is 
underlain  by  the  Conway  mica-schist,  which  dips  under  it  on  the  west.  The 
relations  of  the  two  are  indicated  upon  the  sketch  map  (fig.  11,  p.  197). 
A  few  rods  farther  south,  and  on  the  opposite  side  of  the  road,  the  limestone 
again  buckles  up  twice  through  the  argillite. 

CONTACT   METAMORPHISM    OF    THE    LEYDEN    AEGILLITE    BOKDEEING    THE 

TONALITE    01'   HATFIELD. 

A  band  about  1,300  feet  wide,  bordering  the  tonalite  on  the  west, 
commencing  in  the  woods  west  of  the  school  south  of  Whately  village 
and  extending  southwest  across  Hatfield  to  its  southwest  corner,  shows  on 
the  exact  contact  a  narrow  band  of  green  sericite-gneiss,  and  outside  this  a 

'  Geology  of  Vermont,  Vol.  II,  1861,  Pis.  XV  and  XVI. 
'Ibid.,  p.  497. 


206  GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

very  broad  band  of  cliiastolite-schists,  grading  through  pimpled  schists 
into  the  ordinary  slate. 

The  argillite  is  itself,  in  its  normal  condition,  a  highly  crystalline  rock, 
approaching  the  mica-schists  and  widely  removed  from  the  more  normal 
"argiUite,"  like  that  of  Hoosick  Falls,  New  York.  Much  of  it  is  pimpled 
on  cleavage  surfaces  and  comparable  with  the  knotenglimmerschiefer  of 
the  Germans. 

THE   SKRICITB-GNBISS.    • 

This  rock  may  be  best  studied  above  West  Brook  village,  on  the  south 
line  of  Whately.  In  the  pasture  just  north  of  F.  Bardwell's  the  contact  of 
the  two  rocks  can  be  followed  for  a  long  distance,  and  the  argillite  extends 
in  a  long  point  south  into  the  granite ;  and  farther  south,  in  the  line  of  con- 
tinuation of  this  point,  are  several  masses  of  the  argillite  wholly  surrounded 
by  tonalite.  The  southern  of  these  rises  in  a  vertical  wall  just  east  of  a 
small  pond  in  the  pasture,  and  here  the  exact  contact  can  be  studied.  The 
specimens  described  below  were  taken  from  this  place. 

The  rock  at  contact  is  a  true  sericite-gneiss.  The  foliation  faces  have 
a  dull-green,  serpentine-like  surface,  slickensided  and  with  greasy  feel. 
Broken  transversely  the  thick  sericite  layers  fold  around  small,  white  feld- 
spar grains;  other  layers  run  into  white  quartzite  on  one  side  and  into  a  more 
micaceous  and  less  feldspathic  rock  on  the  other.  Both  varieties  resemble 
exactly  the  Taunus  sericite  rocks  and  are  unlike  the  sericite  or  hydromica- 
schists  of  the  west  border  of  the  county,  where  the  mica  scales  are  much 
more  distinct. 

Under  the  microscope  the  fine-matted  felt  of  a  micaceous  mineral 
(sericite)  makes  a  background  in  which  are  scattered  many  wisps  of  green 
chlorite ;  bright,  highly  refracting,  rounded  grains  exactly  resemble  zircon, 
and  large,  almost  wholly  decomposed  feldspars.  The  latter  are  wholly 
opaque  by  transmitted  light  and  rusty  white  by  reflected  light,  and  often 
show  regular  eight-sided  crystalline  cross-sections.  When  very  thin  and 
very  highly  magnified  these  sections  allow  the  light  to  pass  through  in 
thin,  distant,  parallel  slits,  arranged  at  times  at  right  angles,  at  times  at  an 
angle  approaching  that  of  the  prismatic  cleavage  in  feldspar.  This  seems 
to  come  from  thin  bands  of  the  feldspar  still  undecomposed.  The  zircon 
contains  larg,e  bubbles. 


PLATE   III. 


207 


PLATE    III. 

Fig.  1. — Ley  den  argillite  changed  to  ohiastolite-sohist  in  contact  on  tonalite.  Only  the  bLick  cross  of 
the  chiastolite  remains.  The  crystals  have  been  changed  into  a  mass  of  muscovite  scales  inclosing 
many  staurotite  crystals.     Belmont,  Hatfield.     X7.     Natural  light.     (Seep.  209.) 

Fig.  2. — Sections  of  twins  of  cordierite  from  cordierite-granite.  Brimfield.  X20.  Drawn  with  crossed 
nicols.     (See.  p.  321.) 

Fig  3. — Diorite  from  north  end  of  Paokards  Mountain,  Prescott.     x25.    Natural  light.     (Seep.  342.) 

Fig.  4. — Contact  of  diabase-amygdaloid  and  clayey  limestone,  from  the  upper  surface  of  the  Holyoke 
sheet.  The  curving  of  the  layers  of  the  fine  mud  as  it  flowed  into  the  open  steam  holes  can  be  seen 
on  the  left.  The  large  cavity  was  clogged  by  a  trap  fragment  and  afterwards  filled  by  infiltrated 
calcite.  Rounded  drops  of  the  mud  and  rounded  holes  filled  by  infiltration  can  be  seen  in  the 
trap      C.  Dibbles,  South  Holyoke.     X28.    (See  p.  456.) 

208 


scaloB  inciosinj 


IS  liliert  by  inliltratpti 


U.   8.   OEOLOOICAL  SURVEY 


MONOQRftPH  XXIX      PL.   Ill 


THIN  SECTIONS. 


THE  LEYDEN  AEGILLITE.  209 

Besides  these  exomorphic  effects  of  the  contact,  the  tonalite  shows 
distinctly  an  endoinorphic  influence  of  the  schist  npon  itself.  It  is  finer 
f^rainc'd  than  usual,  though  it  is  granular  to  the  eye,  and  the  deep  flesh- 
red  feldspar  stands  out  on  a  background  green  from  the  abundance  of 
chlorite.  It  is  rudely  foliated,  and  the  foliation  surfaces  are  dull-green, 
like  the  schist  itself,  and  in  transverse  sections  the  microscope  reveals  thin, 
wavY  layers,  winding  in  between  thick  layers  of  the  feldspathic  material, 
which  seem  to  be  made  up  of  the  sericitic  matter  from  the  schist  crowded 
into  the  fissm'es. 

The  main  mass  of  the  argillite  followed  north  from  the  contact  retains 
all  the  complex  contortions  common  in  the  rock,  but  it  is  soaked  full  of 
quartz,  or  quartz  and  feldspar,  the  parallel  bands  being  in  some  cases  sepa- 
rated as  much  as  30""  by  the  intrusion  of  these  new  constituents.  There 
is  also  much  coarse  muscovite,  and  the  rock  is  in  places  greatly  brecciated. 
When  it  is  followed  farther  north  small  staui'olites  appear  and  the  next 
band  is  reached. 

Going  a  short  distance  west  along  the  road  to  the  bridge  over  West 
Brook,  and  then  south  165  feet  along  the  brook,  one  finds  a  fine  contact  of 
the  argillite  and  the  tonalite  exposed.  The  rock  is  here  more  arenaceous, 
and  is  indurated  to  a  homfels. 

THE   CHIAST0LITE-SCHI8T. 

This  rock  (see  fig.  1,  PI.  III.)  may  be  studied  most  conveniently  on  the 
southeast  slope  of  Belmont — a  great  symmetrical  drumlin,  bare  of  trees,  in 
the  northwest  corner  of  Hatfield.  The  original  bedding  of  the  rock  is  here 
clearly  marked  by  bands  of  sandstone  about  an  inch  wide,  separated  by 
argillite  layers  of  twice  this  thickness.  The  whole  is  extremely  contorted, 
and  the  well-marked  cleavage  oversprings  the  sandy  layers  in  almost  every 
case.  The  original  clay  layers  are  now  a  fine,  dark-gray  mica-schist,  to 
which  one  would  hardly  still  apply  the  name  argillite,  and  in  some  places 
it  is  coarsely  muscovitic.  The  schist  is  full  of  chiastolite  crystals,  square 
prisms  about  4°""  wide  and  40™™  long,  enfolded  m  the  layers  of  the  schist, 
as  is  Usual  with  this  mineral.  These  are  now  uniformly  changed  into  a 
shining-white  muscovite  in  matted  scales  (with  traces  of  the  black  cross 
everywhere  remaining),  in  which  small  andalusite  crystals  occur  so  abun- 
dantly as  often  to  occupy  half  the  space.     They  are  in  stout  prisms  nearly 

MON    XXIX 14 


210  GEOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 

a  millimeter  across,  often  twinned  and  well  terminated,  of  red-brown  color, 
and  with  shining  faces.  They  project  in  every  direction  into  the  muscovite, 
and  have  been  plainly  manufactured  from  the  material  of  the  chiastolite  hj 
some  second  metamorphism.  The  muscovite  gave  deep  blue  with  cobalt, 
and  a  purple  flame  when  fused  with  gypsum,  and  fused  with  difficulty  to  a 
white  enamel.  It  gave  the  axial  divergence  of  muscovite.  The  staurolite, 
measured  with  reflecting  goniometer,  gave  oo  PA  co  Pz=129°.  oo  PA 
00  P  06  ^115°  11',  and  twins  after  |  P  06 ,  could  be  determined  optically 
under  the  microscope. 

The  andalusite  crystals  are  orange-yellow  under  the  microscope,  but 
a  central  portion  with  boundaries  parallel  to  the  surface,  even  when  that 
surface  is  plainly  one  of  fracture,  is  colorless  in  most  cases  and  has  a  soft, 
slightly  wavy  striation,  which  a  high  power  shows  to  be  due  to  the  presence 
of  an  immense  number  of  stout  tubular  bodies,  slightly  reddish,  with 
rounded  ends,  often  slightly  twisted  and  varying  in  diameter;  at  times, 
indeed,  passing  into  formless  bodies.  They  are  so  numerous  as  to  give  the 
rock  a  spongy  appearance,  and  are  parallel  to  one  another  and  to  the  verti- 
cal axis  of  the  staurolite.  They  are  0.025"°  long,  COOS""""  across.  Being 
placed  parallel  to  the  axis  of  the  inclosing  mineral,  they  extinguish  with  it; 
but  in  diagonal  position  the  larger  ones  show  color  for  themselves,  and  they 
are  probably  quartz.  Many  sections  of  the  staurolite  are  broken  up  into 
separate  fields  from  twinning,  and  the  rods  have  a  separate  direction  in  each 
of  these  fields.^ 

The  rock  contains,  also,  groups  of  small  garnets.  It  is  a  biotite- 
muscovite-schist.  In  a  quartz-muscovite  background  many  long-notched 
blades  of  a  dark-brown  biotite  and  much  coaly  matter  are  arranged  in  a 
pseudo-fluidal  structure  and  wrap  around  the  chiastolite  crystals. 

'  Lassaulx,  Ueber  Staurolite:  Tschermaks  mineral.  Mittheil.,  Vol.  Ill,  1872,  p.  173,  pi.  3.     Compare 
the  uncolored  figures  where  the  rods  are  stouter  and  more  distant  than  here. 


CHAPTER     VIII. 

THE  BANDS  OF  SILURIAN  SCHISTS  ON  THE  EAST  SIDE 

OF  THE  VALLEY. 

As  noted  in  the  geological  outline  and  the  generalized  section  in 
Chapter  HI,  the  representatives  of  the  Silurian  series  from  the  Hoosac 
schists  to  the  Conway  schists  are  present  east  of  the  river  in  several  narrow 
synclinal  bands  resting  in  the  Monson  gneiss,  which  are  most  conveniently 
described  in  geographical  rather  than  geological  order.  The  series  is 
greatly  simplified  and  is  divisible  into  only  four  or  five  members — a  mus- 
covitic  or  sericitic  and  biotitic  quartzite  below;  next  a  band  of  hornblende- 
schist  (amphibolite) ;  above  this  a  thin-bedded  biotitic  quartz-schist,  which 
I  have  called  the  whetstone-schist,  as  it  is  much  quarried  for  scythestones; 
then  a  garnetiferous  and  graphitic  schist.  These  are,  respectively,  referred 
to  the  Howe  schist,  the  Chester  amphibolite,  the  Savoy  schist,  and  the 
Conway  schist  of  the  western  side  of  the  valley.  Along  the  eastern  border 
of  the  region  the  series  is  still  more  simplified  by  the  disappearance  of 
the  hornblende-schist,  and  the  lower  bed,  which  includes  the  Rowe  and 
Savoy  schists,  is  developed  across  Worcester  County  as  a  monotonoiis,  thin- 
bedded  micaceous  quartzite  which  I  have  named  the  Paxton  whetstone-schist, 
while  the  upper  bed,  the  Conway  schist,  grows  more  metamorphosed  east- 
wardly  and  southerly  and  becomes  rusty,  strongly  fibrolitic,  coarsely 
graphitic,  and  in  places  feldspathic.  This  I  have  named  the  Brimfield  schist 
in  Worcester  County. 

I  have,  then,  to  describe  the  following  areas  (see  geological  map,  PI. 
XXXIV): 

1.  The  Northfield  semisyncline. 

2.  The  Wendell  branch  syncline. 

3.  The  Leverett-Amherst  area. 

211 


212  GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

4.  The  Pelliam-Shutesbury  syncline. 

5.  The  great  central  syncline. 

6.  The  eastern  syncline. 

7.  The  zone  of  contact  and  disturbance  around  the  Belchertown  tonalite. 

8.  The  Wilbraham  syncline. 

9.  The  Monson  syncline. 

10.  The  East  Greenwich-Enfield  syncline. 

THE  KORTHFIELD  SEMISYNCLINE. 

For  a  long  time  it  seemed  to  me  probable  that  the  rocks  at  the  mouth 
of  Millers  River  (see  p.  295)  and  those  here  under  discussion  were  a  con- 
tinuation of  the  Bernardston  series,  and  thus  of  known  age;  and  because 
of  the  importance  of  the  question  I  have  studied  these  areas  with  great 
care  and  describe  them  in  somewhat  greater  detail  than  usual,  and  com- 
pare them  with  the  Bernardston  series,  in  order  that  the  grounds  for 
accepting  or  rejecting  the  correlation  suggested  above  may  be  clearly 
seen.  The  fold  here  described  lies  along  the  east  line  of  Northfield,  in 
the  Warwick  quadrangle. 

The  comparison  of  this  series  with  the  Silurian  beds  west  of  the  river 
forms  the  first  step  in  the  correlation  of  the  beds  east  and  west  of  the  river. 
The  gneiss  a  in  the  sections  below  (p.  2 1 3)  is  identical  with  the  Becket 
gneiss^  The  beds  h  and  c  are  close  lithological  representatives  of  the 
Rowe  schist.  The  bed  A  agrees  well  with  the  Chester  amphibolite.  The 
whetstone-schist  e  is  closely  like  the  Savoy  quartzose  schist,  while  the 
bed  /  is  the  exact  counterpart  of  the  Conway  schist  in  all  its  peculiarities, 
even  to  the  presence  of  spodumene  and  cleavelandite  dikes. 

GENERAL    DESCRIPTION. 

The  rocks  were  first  compressed  into  a  great  syncline  in  the  Monson 
gneiss,  the  axis  of  the  syncline  pitching  to  the  north,  and  then  a  north-south 
fault  occurred  along  this  axis,  and  the  rocks  on  the  east  were  upheaved  by 
about  the  thickness  of  the  series  (1,890  feet),  and  so  far  eroded  that  only 
a  remnant  of  the  lowest  bed  remains  on  the  eastern  half  Then  several 
transverse  faults  cut  across  the  beds,  and  one  is  notable  from  the  amount 
of  drag  which  the  beds  on  the  north  side  of  it  have  suffered  at  their  south 


THE  NOKTIIFIELD  SEMISYNCLINE.  213 

ends  from  friction  ao-ainst  tlie  wall  of  the  fault  on  the  south;  for  an  inspec- 
tion of  tlic  niiip  will  sliow  tliat  to  the  north  of  this  transverse  fault  tlie 
strike  of  all  the  beds  bends  from  a  north-south  direction  round  to  an 
easterly  direction.  It  is  remarkable,  also,  that  to  the  north  of  this  fault  all 
the  beds  of  the  western  flank  of  the  syncline,  as  well  as  the  remnant  of  the 
eastern  flank,  are  inverted  and  now  dip  uniformly  to  the  west. 

The  topography  of  the  region  is  to  an  exceptional  degree  dependent 
upon  its  geological  structure.  Each  of  these  transverse  faults  is  now  the 
gorge  of  a  brook. 

The  upper  beds  of  the  series — the  Conway  mica-schists — are  the  most 
resistant  to  erosion,  and  form  the  high  hills,  which  are  pushed  forward  or 
recede  as  the  block  of  mica-schist  of  which  each  is  made  is  pushed  forward 
or  back  by  the  faulting.  The  amphibolite  is  more  rapidly  eroded,  and  it 
forms  a  deep  furrow  across  the  town,  in  which  runs  what  is  appropriately 
called  the  Grulf  road,  the  word  gulf  being  used  in  this  sense  in  several 
places  in  western  Massachusetts.  The  basal  qiiartzite  is  also  resistant  and 
mantles  over  the  gneiss  of  Brush  and  Crag  mountains  in  sharp,  angular 
ridges,  which  can  be  seen  and  recognized  so  far  off  as  the  station  at  Millers 
Falls  as  peculiar  and  not  like  the  forms  of  the  gneiss.  The  Gulf  road  men- 
tioned above  runs  south  from  Northfield  to  Erviug,  at  the  east  base  of  Brush 
and  Crag  mountains,  and  continues  a  long  way  on  the  hornblende-schist  of 
this  sei'ies,  and  here  the  whole  may  be  best  studied. 

'THE    GULF    ROAD    SECTIONS. 

Two  miles  south  on  this  road  a  side  road  goes  up  onto  the  mountain 
westerly  to  the  house  of  Mrs.  J.  Robbins,  and  a  little  farther  south  a  similar 
blind  road  runs  east  to  the  house  of  R.  H.  Minot.  The  whole  series  is 
well  exposed  along  this  line,  and  it  is  described  in  the  following  section, 
beginning  at  the  west  end: 

The  granitoid  biotite-gneiss  (a),  which  makes  the  mass  of  Brush 
Mountain,  forms  the  base  of  the  section.  It  is  the  northern  portion  of  the 
large  Pelham  area  of  the  Monson  (Cambrian)  gneiss.  The  line  of  boundary 
between  the  basal  quartzite  (the  Rowe  schist)  and  this  gneiss  runs  beneath 
the  Robbins  house,  making  a  large  cvirve  to  the  east,  and  the  two  rocks  are 
unconformable.  This  is  shown  by  the  fact  that  the  gneiss  has  strike  N. 
40°-50°  W.,  dip  25°-3o°  E.,  while  the  quartzite  above  has  strike  N.  15°  W., 


214       GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

dip  10°-15°  E.;  and  as  one  goes  east  from  the  boundary  down  the  steep  hill 
and  across  the  qnartzite  the  dip  of  this  latter  rock  incr(3ases  gradually  to 
45°,  showing  that  the  quartzite  mantles  over  the  gneiss.  The  qnartzite  (6) 
is  here  quite  micaceous,  the  mica  being,  as  usual,  a  shining-white  muscovite, 
or  often  a  sericite.  In  places  coarse  patches  of  biotite  scales  also  occvir. 
Southward  along  the  crest  of  the  hill  this  bed  is  in  one  place  distinctly 
conglomeratic,  pebbles  of  quartz  about  an  inch  across  and  much  flattened 
by  the  compression  of  the  rocks,  making  up  the  mass  of  the  rock  in  a  great 
vertical  clifP  looking  west.  West  of  C.  T.  Swan's,  where  the  1,200-foot  con- 
tour crosses  the  road,  200  rods  south  of  the  Robbins  house,  on  the  mountain 
crest,  it  is  a  very  vitreous  quartzite,  resembling  an  aggregation  of  the  quartz 
nodules  in  common  mica-schist.  Some  beds  here  also  abound  in  a  shining- 
white  mica,  and  others  carry  a  little  biotite.  The  thickness  opposite  C.  T. 
Swan's  house  is  575  feet.  This  is  followed  by  a  very  coarse,  wavy,  very 
micaceous,  often  sericitic,  garnet-bearing  schist  of  white  color  (c).  It  is 
40  feet  thick  on  the  Robbins  road;  in  the  section  opposite  C.  T.  Swan's 
house,  65  feet.     (5)  and  (c)  are  the  equivalents  of  the  Rowe  schist. 

The  amphibolite  (d),  or  the  Chester  amphibolite,  is  a  greenish-black 
rock  of  fine  grain,  separating  into  thin  plates  which  have  a  ligniform  struc- 
ture from  the  perfect  "stretching"  of  the  rock.  It  is  usually  of  even  grain 
and  free  from  all  accessories.  Nodules  of  albite  and  ilmenite  occur  rarely. 
It  is,  on  the  Robbins  section,  about  500  feet  thick;  on  the  Swan  section, 
330  feet. 

The  whetstone-schist  (e),  or  the  Savoy  schist,  is  a  gray,  arenaceous 
biotite-schist  or  micaceous  quartzite.  The  biotite  is  in  thin  scales,  not 
concentrated  upon  foliation  planes,  but  scattered  sparingly  and  evenly 
through  the  rock.  Near  the  top,  at  R.  H.  Minot's  house,  is  a  very  rusty 
layer  full  of  coarse  garnet  and  hornblende.  In  the  Swan  section  its  thick- 
ness is  612  feet. 

Then  follows  a  coarse  muscovite-schist  (/),  often  very  micaceous.  It 
is  affected  by  both  a  fine  corrugation  of  the  foliation  surfaces  and  a  general 
twisting  and  contortion  of  the  folia  themselves.  It  is  graphitic  and  abounds 
in  garnets  and  staurolite,  the  latter  especially  abundant  toward  the  base. 
Its  thickness  in  the  Swan  section  is  354  feet,  but  here  the  whole  thickness 
is  not  present  because  of  the  fault;  a  little  farther  south,  opposite  the 
schoolhouse,  it  is  445  feet.     This  is  identical  wath  the  Conway  schist. 


TIIIO  NOIITHFIELU  SEMISYNCLINE.  215 

In  tlie  Swan  section  cuutiuued  east  aloiif)-  tlie  Minot  mad  the  fault  and 
the  contact  of  tlie  mica-schist  (./'),  dipping  30°  E.,  with  the  basal  quartzite 
dijipino-  15°  W.,  can  be  clearly  seen.  The  latter  is  here  largely  a  two- 
jnica-gneiss  of  arenaceous  structure,  with  shining-white  inuscovite. 

In  the  section  opposite  School  No.  10,  where  the  road  branches  a  little 
way  south  of  Swan's  house,  a  bed  of  granite  8  feet  thick  occupies  the  place 
of  the  fault,  and  to  the  east  of  it  is  a  thick-bedded  quartzite,  which  at  top 
becomes  a  coarse,  white,  sandy  muscovite-schist  with  wavy  folia  and  carry- 
in"-  o-arnets.  The  whole  has  a  thickness  of  307  feet,  and  represents  the 
basal  quartzite  (b)  and  a  little  of  the  mica-schist  (c)  above  it.  It  belongs 
to  the  eastern  flank  of  the  syncline,  and  is  brought  up  by  a  fault  whose 
throw  must  be  at  least  equal  to  the  thickness  of  the  strata  c  to  e,  or  1,890 
feet.  The  western  flank  of  the  syncline  dips  normally  E.  30°-35°,  while 
the  remnant  of  the  eastern  flank  is  overturned  upon  the  mica-schist  and 
dips  easterly  against  a  great  dike  of  pegmatite. 

SECTIONS    NOETH    AND    SOUTH    OF    THE    OLD    WARWICK    ROAD. 

The  mica-schist  (/)  continues  north  as  a  high  ridge  which  terminates 
in  the  prominent  hill  south  of  Gr.  Alexander's,  called  locally  Tom  Field's 
hill,  whose  crest  and  western  slope  are  underlain  by  the  corrugated  schists, 
while  the  fault  runs  along  just  east  of  the  highest  part  of  the  hill.  The 
schists  sink  down  northwardly  to  the  east-west  fault  Avhich  follows  closely 
the  line  of  the  old  Warwick  road,  upon  which  A.  Moore's  house  stands. 

North  of  this  fault  the  main  longitudinal  fault  is  continued  north  with 
little  or  no  interruption,  passing  just  east  of  A.  Moore's  house,  but  the 
whole  series  of  schists,  which  forms  the  western  half  of  the  anticline  and 
which  has  been  already  described,  is  overturned  so  that  it  dips  everywhere 
50°-70°  to  the  west.  This  continues  to  the  next  road  on  the  north,  the 
present  Northfield-Warwick  road,  and  all  the  members  of  the  series  are 
unchanged  except  the  bed  of  rusty  garnet-hornblende  rock  at  the  Minot 
house,  which  becomes  a  persistent  and  thick  bed  of  hornblende-schist  in 
the  upper  portion  of  the  whetstone-schist.  Another  fault  cuts  off  the 
southwest  portion  of  this  area,  and  this  part  is  placed  in  normal  relation  to 
the  north  end  of  the  gneiss  area  to  the  southwest,  striking  east  and  west, 
and  dipping  north  away  from  the  gneiss. 

The  next  transverse  fault  to  the  north  follows  the  Northfield-Warwick 


216       GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

road  already  mentioned.  To  the  north  of  this  line  the  whole  series  of  the 
schists  is  moved  horizontally  to  the  west  for  a  considerable  distance, 
dragging  upon  the  fault  so  that  the  strata  bend  around  from  the  normal 
north-south  direction  to  a  direction  due  east  at  the  faiilt.  The  series  main- 
tains, however,  the  inverted  position  and  constant  westerly  strikes  of  the 
portion  south  of  this  fault. 

The  explanation  of  this  complex  system  of  faults  seems  to  be  that  the 
great  Pelham  gneiss  mass  on  the  west  ends  just  where  the  first  of  these 
tranverse  faults  appears,  while  to  the  east  of  the  great  north-south  fault  an 
equally  high  gneiss  area  extends  north  across  the  whole  town  of  Warwick. 
When  the  east-west  compression  acted  on  these  beds  they  were  on  the  south 
of  the  first  transverse  fault,  supported  by  the  north  end  of  the  Pelham  gneiss 
in  Brush  Mountain,  while  on  the  north,  finding  firm  support  only  at  a  lower 
level,  they  were  thinist  westward  and  overturned. 

PEGMATITE    DIKES    AND    MINERALS. 

A  curious  point  of  resemblance  between  the  Conway  schists  of  the 
west  side  of  the  county  and  the  same  schists  in  this  section— the  upper  beds 
(/)  of  the  series — is  the  appearance  of  large  granite  dikes  carrying 
spodumene,  cleavelandite,  tourmaline,  columbite,  and  beryl.  One  great 
dike  of  this  character  appears  in  the  yard  of  M.  A.  Brown,  on  the  Win- 
chester road  and  just  over  the  town  line  in  Vermont,  and  is  there  filled 
with  poor  crystals  of  spodumene.  On  the  top  of  Strowbridge  Hill,  a  half 
mile  south,  I  found  the  same  dike,  or  its  successor  on  the  line  of  strike, 
filled  with  cleavelandite  and  a  little  tourmaline ;  and  the  same  distance  again 
to  the  south  along  the  line  of  strike  is  the  fine  columbite  locality  discovered 
by  Mr.  M.  A.  Brown.  This  may  be  reached  by  following  the  lane  back  of 
L.  A.  Moody's  house,  east  through  the  woods  nearly  to  the  Warwick  road. 
Farther  south,  on  the  Minot  section,  the  same  coarse  granites  carry  immense 
beryls,  and  just  where  the  beds  cross  the  town  line  to  the  south  the  granite 
abounds  in  spodumene. 

This  is  one  of  those  curious  and  inexplicable  matters  of  paragenesis, 
and  it  derives  its  problematical  character  from  the  fact  that  the  pegmatites 
cutting  all  the  other  beds  are  wholly  wanting  in  those  minerals  containing 
rare  elements,  except  those  penetrating  the  comparatively  recent  Conway 
schist,  which  at  distant  localities  on  both  sides  of  the  Connecticut  River 
carries  them  abundantly. 


SILUKIAN  SCHISTS.  217 

THE   VVKXWELIj   HKANCII  SYNC  LINE. 

Tn  the  southwest  corner  of  Warwick,  at  Harris's  pond,  a  subordinate 
syncHue  hrauclies  oft'  from  the  great  central  synchne  next  to  be  described. 
It  is  directed  first  west,  bends  round  south  in  Barber's  hill,  in  which  it 
passes  tlu'ough  a  corner  of  Erving,  and  crosses  the  river  and  extends  south 
into  Wendell,  where  it  ends  abruptly  against  a  fault. 

At  the  point  where  it  branches,  west  of  Barber's  pond,  the  uppermost 
bed  in  the  syncline  is  a  dark,  graphitic  mica-schist  (Conway)  with  abundant 
transverse  biotite  and  with  many  staurolites  and  small  garnets.  It  is  thus 
exactly  like  the  corresponding  u^jpermost  beds  (/)  in  the  Northfield  syncline 
already  described,  and  so  forms  an  important  link  in  the  chain  of  evidence 
in  favor  of  the  identity  of  the  series  I  am  here  describing  with  the  similar 
series  across  the  Connecticut  Valley,  with  which  I  have  associated  it. 

There  is  a  fine  section  of  the  beds  of  this  series  exposed  in  the  railroad 


Cfjestvr/impfT/ho/if^.  Granite    t:hesferAi77phibolif^'^  CfiesferAtnphibolifv.  Conway  Sc/?/st. 

Savoy  Schi'si: 

(fflHETSTOHEj 

JFiG.  13. — Section  on  railroad  east  of  Erving  station. 

cutting  east  of  Erving  and  opposite  the  piano  factory  (fig.  13),  though  the 
beds  are  thrown  into  such  confusion  that  no  conclusions  can  be  drawn  con- 
cerning their  sequence. 

Entering  the  cutting  from  the  west,  several  large  outcrops  of  amphibo- 
lite  appear  through  the  sands,  and  just  beyond  is  a  great  boss  of  granite 
curiously  molded  together  with  amphibolite,  which  is  changed  to  biotite- 
schist  at  its  contact  with  the  granite,  which  carries  upon  its  back  a  great  mass 
of  a  gray  whetstone-schist  extremely  contorted.  This  is  followed  by  a 
great  body  of  amphibolite,  in  places  much  contorted.  It  contains  albite 
and  calcite  in  veins,  and  nodules  of  epidote  often  15""  long.  To  the  east 
this  is  followed  by  a  coarse,  gray  mica-schist  with  garnets  (co  0)  and  small 
staurolites. 

All  these  beds  resemble  closely  the  corresponding  ones  of  the  North- 
field  section,  which  ends  just  north  of  this  point,  and  this  serves  to  connect 
the  two  and  unite  both  with  the  western  area.     It  serves  also  to  illustrate 


218       GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

the  extreme  complexity  which  characterizes  these  beds  in  their  progress 
south  through  Wendell  until  they  are  cut  off  by  the  fault  east  of  Wendell 
Center. 

This  may  be  well  studied  by  going  up  the  Osgood  Brook  road  and 
turning  onto  the  high  hill  north  of  S.  Stevens's  house.  Everywhei'e  the 
beds  are  thrown  into  great  confusion  and  filled  with  granite  dikes,  so  that 
the  representation  on  the  map,  though  the  result  of  much  work,  gives  only 
a  general  view  of  the  main  facts.  The  whole  southern  portion  of  the  area 
is  underlain  by  whetstone-schist,  which  has  been  quarried  here  for  scythe- 
stones,  and  for  this  reason  the  hill  is  locally  called  Whetstone  Hill. 

THE   liEVEBETT-AMHEEST  AREA. 

THE  AMPHIBOLITE  AND   MICA-SCHIST  SERIES  ALONG  THE  EAST  SIDE  OF  THE 
CONNECTICUT    BASIN    FROM    LEVERETT    SOUTHWARD. 

The  bottom  of  the  Connecticut  Basin,  as  the  area  of  transition  between 
the  closely  folded  rocks  with  vertical  dips  on  the  west  and  the  undulating, 
almost  horizontal  gneisses  on  the  east,  is  underlain  by  a  broad  band  of 
extremely  disturbed  rocks,  faulted,  soaked  full  of  granite  and  quartz  veins, 
and,  especially  along  a  line  extending  quite  across  the  State  and  situated 
at  the  immediate  foot  of  the  eastern  plateau,  most  thoroughly  crushed,  brec- 
ciated,  slickensided,  and  filled  with  veins  of  hematite,  albite,  quartz,  and 
epidote,  or  mineral  veins  of  the  "baryta-lead  formation." 

It  is  just  along  this  line  of  maximum  disturbance  that  a  series  of  rocks 
which  forms  a  repetition  of  those  described  in  Northfield  (p.  212)  runs 
south  from  the  mouth  of  Millers  River  at  the  great  bend  of  the  Connecticut. 

The  same  succession — feldspathic  quartzite,  or  two-mica-gneiss  (V),^ 
amphibolite  (c/),  whetstone-schist  (e),  and  spangled  mica-schist  (/) — can  be 
made  out,  but  with  difficulty,  and  all  the  members  are  much  altered  and 
thrown  into  great  confusion,  so  that  the  assignments  made  upon  the  map, 
though  the  result  of  long  study,  are  given  with  much  hesitation. 

For  convenience  the  amphibolite  and  the  quartzose  bands,  the  quartzite 
below  and  the  whetstone-schist  above,  are  described  together,  while  the 
equivalent  of  the  spangled  or  Conway  mica-schist — the  Amherst  feldspathic 
mica-schist — is  discussed  apart. 

'  The  italic  letters  a-f  refer  to  section  given  on  pp.  213-214. 


THE  LEVEKETT  AMnEUST  AREA.  219 

NORTH    LEVERETT    (GREENFIELD    (iUA])RANGLE,    SOUTHEAST    CORNER). 

Still  turtlier  south,  and  just  south  of  the  railroad  crossing  over  Locks 
Pond  Hrook,  the  series  appears  in  Stoddard  Hill  and  forms  a  narrow  band 
running-  south  between  the  gneiss  and  the  red  sandstone.  It  is  largely  cut 
by  granite,  which  has  replaced  it  over  great  areas,  and  this  rock  shows  often 
the  peculiar  structure  adverted  to  in  the  description  of  the  Millers  River 
section  (p.  295).  The  materials,  of  a  very  coarse  pegmatite,  form  a  dis- 
tinct!}" foliated  mass  from  the  parallel  arrangement  of  the  large  muscovite 
scales,  and  agree  in  dip  and  strike  with  the  surrounding  schists.  It  seems 
also,  where  it  comes  in  contact  with  the  different  beds  of  the  series,  to  have 
absorbed  larg'e  quantities  of  their  material  into  its  mass,  being  near  the 
amphibolite  a  fine  two- mica-granite  of  coarse  but  very  even  texture,  as 
above  the  cemetery  in  Leverett,  and  finer-grained,  more  quartzose,  and 
almost  free  from  mica  in  the  neighborhood  of  the  quartzite,  as  north  of  the 
cemetery  in  North  Amherst.  Furthermore,  the  granite  seems  to  have 
assumed  a  schistose  character  where  it  has  intruded  itself  into  the  place  of 
the  more  schistose  members  of  the  series,  as  if  by  a  kind  of  pseudomorphism 
it  had  inherited  their  structure. 

The  series  in  Leverett  is  divided  into  two  portions  by  an  exceptionally 
large  mass  of  granite.  The  northern  portion  presents  a  section,  from  east 
to  west  as  follows:  [a)  Monson  gneiss,  (6)  basal  quartzite,  (c)  mica-schist, 
h  and  c  together  representing  the  Rowe  schist,  (cl)  Chester  amphibolite, 
(e)  granite,  here  occupying  the  position  of  the  whetstone  (Savoy)  schist, 
(/)  spangled  or  Conway  mica-schist — all  dipping  westward  from  the  gneiss. 
East  of  E.  Gr.  Reynolds'  the  quartzite  is  feldspathic  and  like  the  Bernardston 
upper  quartzite.  The  mica-schist  (c)  and  the  amphibolite  {d)  agree  com- 
pletely with  the  corresponding  beds  of  the  Northfield  section.  In  Stoddai'd 
Hill,  325  feet  east  of  the  railroad,  the  latter  is  a  coarse  hornblende-schist, 
in  places  very  biotitic,  in  places  massive. 

The  mica-schist  (/),  which  I  identify  with  the  Conway  mica-schist,  is 
the  first  outcrop  we  meet,  going  south,  of  a  rock  which,  from  its  expansion 
across  Amherst,  I  have  called  the  Amherst  feldspathic  mica-schist.  Its 
appearance  here  in  the  same  position  as  the  Conway  mica-schist  of  North- 
field  is  one  of  the  reasons  for  identifying  the  whole  mass  with  the  rock  so 
named  across  the  river.     The  subject  is  fully  discussed  on  page  222. 


220       GEOLOGY  OP  OLD  HAMPSHIRE  COUNTY,  MASS. 

The  rock  here  is  a  coarse,  very  rusty,  garnetiferous  and  feldspathic 
mica-schist.  It  is  surrounded  by  g-ranite,  and  floats,  as  it  wei-e,  in  it,  and  is 
largely  injected  with  granite  veins,  which  at  times  so  greatly  predominate 
that  one  must  describe  the  area  as  occupied  by  granite  containing  parallel 
filaments  and  thin  sheets  of  schist.  The  latter  do,  nevertheless,  preserve  the 
dip  and  strike  of  the  main  mass,  while  the  granite  has  also  its  constant  rude 
dip  and  strike  in  the  same  sense  as  if  the  process  had  here  been  carried  a 
step  farther,  and  the  granite,  being  injected  into  and  opening  out  the  laminae 
of  the  schists  and  cooling  between  them,  had  retained  a  lamination  from 
them  after  they  had  been  wholly  or  almost  wholly  absorbed  into  its  mass. 

The  schists  agree  so  closely  with  the  Conway  mica-schist  where  it 
comes  into  the  granitic  areas  on  the  west  of  the  river,  directly  opposite,  that 
I  have  no  hesitation  in  following  the  stratigraphical  indications  and  associat- 
ing them  together. 

LEVERETT  CENTER. 

Southwest  of  the  great  mass  of  granite  another  long  strip  of  the  rocks 
of  the  series  runs  from  A.  Field's,  on  the  road  east  of  Mount  Toby,  southeast 
through  Leverett  Center  and  South  Leverett  and  on  into  Shutesbury,  to 
end  in  Mount  Boreas  at  Adams  Mills. 

Just  above  Leverett  Center  the  gneiss  is  notched  into  it  by  a  series  of 
faults.  The  amphibolite  runs  down  the  eastern  border  of  the  strip.  It  is 
for  the  most  part  a  thin- fissile  rock,  often  stretched  and  ligniform,  of  dark- 
green  color,  made  up  of  magnetite,  feldspar,  and  hornblende,  the  latter  in 
elongate  needles,  and  all  parallel  to  one  another  and  to  the  line  of  stretching. 
It  is  at  times,  as  south  of  A.  Field's,  a  tremolite-schist.  The  mineral  is  in 
short,  stout  prisms,  without  feldspar,  quartz,  or  ore.  Rarely  the  lower  mica- 
schist  (c)  appears  between  it  and  the  gneiss,  but  the  whole  series  is  in  the 
greatest  confusion  and  is  also  largely  covered  by  till  and  sand. 

THE  SAVOY  SCHIST,  OR  WHETSTONE-SCHIST. 

The  center,  and  by  far  the  larger  portion  of  the  series,  is  taken  up  by 
an  arenaceous  rock,  slightly  micaceous,  and  at  times  slightly  hornblendic, 
which  is  at  times  crushed  to  pieces  and  jointed  and  cut  by  many  quartz 
and  specular  iron  veins,  the  rock  itself  being  thoroughly  silicified  and  ren- 
dered compact  and  hornstone-like.    It  is  often  exactly  like  the  corresponding 


THE  LEVEllETT-AMHEKST  AKEA. 


221 


stratum  in  the  Northfield  Mouutaiii.  It  abounds  often  in  a  green,  cliloritic 
mineral,  and  along  the  road  east  of  Mount  Toby  it  is  abundantly  brecciated" 
aud  cemented  by  hematite. 

Along  the  east  side  of  Mount  Toby  the  whetstone -schist  appears  in  the 
base  of  the  mountain.  Its  first  outcrop  is  just  south  of  the  Mount  Toby 
station,  aud  it  can  be  followed  from  this  point  south  to  the  first  brook, 
where  the  contact  of  the  Mount  Toby  conglomerate  upon  the  whetstone  is 
40  feet  above  the  railroad  (436  feet  above  sea  level),  and  on  to  the  second 
brook,  where  the  contact  is  12  feet  above  the  railroad.  This  greatly  lessens 
the  probable  thickness  of  the  conglomerate  of  Mount  Toby. 

In  the  extreme  northeastern  corner  of  Amherst  there  is  by  the  roadside 
a  small  outcrop  of  thin-fissile,  stretched  hornblende-schist  in  the  whetstone, 
exactly  resembling  that  found  in  the  Northfield  section.  It  can  be  traced 
northwest  past  the  brook-crossing  east  of  A.  Adams's  house,  and  connects 
with  the  bed  at  Leverett  Center.  It  is  a  beautiful  rock  under  the  micro- 
scope. The  perfectly  parallel  hornblende  blades  have  the  strong  pleoch- 
roism  and  absorption  of  the  Chester  amphibolite,  large,  rounded  grains  of 
magnetite  are  frequent,  and  the  whole  is  placed  in  a  background  of 
untwinned  feldspar  grains.     An  analysis  of  the  rock  by  Mr.  L.  G.  Eakins  is 


given 

below : 

Analysis  of  liornblende-schist  from  Amherst. 

■ 

SiOi                                                               .          

Per  cent. 

47.56 
1.24 

16.13 

trace 

1.80 

9.39 

.08 

trace 
6.67 
9.21 
1.58 
2.52 
3.51 
.21 

TiOi 

Al.Oa.                         .                                   .               

Cr.,03                                                                            

Fe^Os                                                                                    

FeO.                                 ...              

MnO  ..                  .           .                                          

BaO                                                                                    

CaO                                                                                                   

Mo-O                                                                                                

KjO 

Na^O                                                                  

HO                                                                              

P.,0, 

99.90 

222       GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

THE  AMHERST  FELDSPATHIC  MICA-SCHIST  (CONWAY  SCHIST). 

« 

LEVERETT. 

West  of  the  band  of  whetstone-schist  in  South  Leverett  begins  the 
broad  area  covered  by  the  Amherst  feldspathic  mica-schist  and  granite  in 
inextricable  confusion.  It  is  in  this  northern  portion  so  purely  granite,  and 
the  shreds  of  schist  are  so  impregnated  with  granitic  material,  that  I  have 
marked  but  a  small  portion  as  schist  upon  the  map. 

AMHEBST. 

The  Conway  mica-schist  of  the  western  side  of  the  Connecticut  Valley, 
where  it  approaches  the  great  masses  of  granite  from  Williamsburg  to 
Montgomery,  can  be  seen  along  both  dip  and  strike  to  become  more 
coarsely  crystalline  and  feldspathic,  while  the  plumbaginous  material  dis- 
appears or  crystallizes  into  graphite  and  thus  colors  the  rock  less.  The 
garnet  and  staurolite  also  disappear  in  large  measure,  and  a  rock  results 
closely  comparable  to  that  which  underlies  the  towns  of  Amherst  and 
Hadley 

Furthermore,  the  same  mica-schist  in  Horse  Mountain,  on  the  western 
line  of  Hatfield,  dips  west  and  formerly  mantled  over  the  hornblende- 
granite  at  its  eastern  foot.  It  is  here  not  greatly  different  from  much  of 
the  Amherst  rock,  and  I  assume  that  it  reappears  in  the  nearest  outcrops 
on  the  east  of  the  river  in  Mount  Warner,  where  it  forms  a  much-disturbed 
syncline,  and  then  extends  across  Amherst,  on  its  eastern  border  dipping 
west — that  is,  away  from  the  hornblendic  band  which  underlies  it,  and  which 
I  have  already  traced  across  Pelham. 

Starting  thus  from  the  exact  lithological  identity  of  the  Conway  mica- 
schist  of  Northfield  on  the  east  and  that  of  Coleraine  directly  opposite,  west 
of  the  Connecticut,  I  have  shown  that  the  coarse  mica-schists  of  the  north- 
west of  Leverett  occu^jy  the  same  stratigraphical  position  as  the  Conway 
schist  in  Northfield,  and  then  have  traced  the  Leverett  schists  southward 
into  continuity  with  the  Amherst  schist.  The  latter  is  then  shown  to  be 
identical  with  the  altered  representative  of  the  Conway  schist  on  the  west 
of  the  river  just  opposite,  and  the  same  parallelism  can  be  proved  clear 
across  the  State. 


THE  LEVERETT-AMIIEHST  AEEA.  223 

It  remains  to  discuss  the  rock  itself  and  see  how  far  it  still  shows  i)oints 
of  resemblance  to  the  calciferous  mica-schists. 

The  r(H'k  appears  in  Mount  Wai'ner,  in  an  area  north  of  South  Am- 
herst, beneath  the  till  in  the  ridge  from  Amherst  village  to  North  Amherst, 
and  in  the  rocky  region  along  the  north  line  of  the  town  and  extending 
over  into  Leverett.  It  is  everywhere  greatly  cut  by  granite  dikes  and 
thoroughly  impregnated  with  granitic  material,  especially  in  the  latter  area, 
where  it  exists  only  as  shreds  in  an  almost  continuous  expanse  of  granite. 
This  is  clearly  the  eastern  border  of  the  great  granite  area  which  has  its 
center  in  Williamsburg,  on  the  west  of  the  valley,  and  extends  thence  east 
beneath  the  Trias  and  finds  its  eastern  border  closely  coincident  with  the 
Conway  mica-schist  in  which  it  has  its  whole  development. 

Description. — The  rock  is  in  composition  a  gneiss,  in  texture  a  coarse 
schist,  so  that  Dr.  Hitchcock  sometimes  gave  it  one  name  and  sometimes 
the  other.  It  varies  from  a  coarse  muscovite-schist,  made  up  almost  wholly 
of  mica  in  large  scales,  to  a  schistose  gneiss,  at  times  containing  large 
rounded  masses  of  fine  microcline.  It  is  always  rusty,  and  very  generally 
contains  pyrite,  so  that  the  water  from  several  wells  along  the  western 
border  of  Amherst,  when  low,  curdles  inilk  and  gives  strong  reaction  for 
sulphuric  acid,  and  in  new  openings  fissures  of  the  rock  are  covered  with 
fine  sheets  of  pyrite  of  very  recent  origin. 

Along  the  western  edge  of  the  ridge,  appearing  in  my  well  on  the 
Northampton  I'oad,  and  in  that  of  President  H.  H.  Goodell  farther  north, 
as  also  in  Mount  Warner,  is  a  band  the  lamination  surfaces  of  which  are 
spangled  with  large,  rounded,  equidistant  plates  of  silvery  muscovite  filled 
with  fine  radiated  needles  of  fibrolite,  a  peculiarity  which  appears  on  a 
much  more  extensive  scale  in  the  more  easterly  bands  of  the  mica-schist. 
This  fibrolite  occurs  where  the  road  over  Mount  Warner  rounds  a  rocky 
spur  at  the  southwest  corner  of  the  mountain,  and  this  is  the  most  western 
appearance  of  fibrolite  in  the  schists. 

In  excavations  at  the  north  end  of  Prospect  street,  in  the  hill  east  of 
North  Amherst  railroad  station,  and  in  the  large  outcrop  near  South  Amherst, 
there  are  intercalated  beds  of  an  eclogite-like  rock,  a  massive  quartz-garnet- 
hornblende  rock  containing  shining  scales  of  graphite.  The  garnet  is  light- 
red,  and  is  intimately  mixed  with  the  quartz  to  form  a  groundmass  which 
the  hornblende  penetrates  in  stout,  parallel  rods,  transverse  to  the  bedding, 


224  GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

of  such  size  and  arrangement  that,  on  weathering,  the  rock  presents  very 
closely  the  appearance  of  a  scolithus  sandstone,  and  I  tried  for  a  long  time 
to  persuade  myself  that  this  was  the  case.  I  am  now  inclined  to  connect 
these  beds  with  the  beds  of  tough  hornblende  rock  carrying  black  garnet 
which  appear  in  the  Conway  schists,  either  alone  or  as  a  selvage  to  the  beds 
of  black  limestone,  as  both  have  the  same  composition — quartz,  garnet, 
hornblende,  and  graphite.     The  hornblende  changes  often  to  serpentine. 

A  very  similar  rock  appears  on  the  eastern  border  of  the  tonalite  in 
Hatfield  (near  the  house  of  J.  Glasner),  and  is  probably  a  product  of  the 
contact  action  of  the  latter  upon  a  limestone  bed  of  the  Conway  schist.  The 
exposures  are  not  sufficient  to  make  its  relations  clear. 

Correlation  of  Amherst  schist. — As  a  feldspathic  mica-schist  the  rock 
resembles  the  feldspathic  varieties  of  the  Conway  schist  on  the  west  side  of 
the  valley,  especially  in  its  southern  extension,  as  about  Russell.  In  this 
assignment  I  have  been  influenced  by  stratigraphical  considerations,  by 
the  very  general  content  of  graphite,  by  the  common  traces  of  calcite, 
by  the  probable  derivation  of  the  eclogite-like  rock  from  bands  of  arena- 
ceous limestone  like  those  common  in  the  calciferous  mica-schist,  and  by  the 
fact  that  these  Amherst  schists  closely  resemble  the  calciferous  mica-schist 
immediately  opposite,  in  Williamsburg,  where  it  is  most  influenced  by 
the  granite  and  develops  into  a  fibrolite-schist  like  the  neighboring  bands 
of  the  same  schists  on  the  east. 

Minerals  in  the  Amherst  schists. — Apart  from  the  baryta-lead  veins, 
described  under  mineral  veins  in  Chapter  XIV,  there  have  occurred  the 
following  minerals  in  the  schists: 

(1)  Essonite  and  graphite;   west  slope  of  Mount  Warner. 

(2)  Heulandite  in  perfect,  deep-red  crystals,  with  rosettes  of  a  newly 
formed  pyrite ;  head  of  Prospect  street,  Amherst,  and  at  the  college  grove 
well  with  pyrophylhte.  oo  P  do  (010),  —  2  P  o6  (201),  2  P  oo  (201),  0  P 
(001),  30  P  (110). 

(3)  Pyrophyllite  after  feldspar,  fibrolite,  and  biotite. 

In  a  well  at  the  northwest  corner  of  the  college  grove  the  rock  was 
a  biotite-schist,  much  impregnated  with  granite,  which  swells  to  lenses  of 
the  coarsest  pegmatite  many  feet  in  length.  Associated  with  these  granite 
lenses  are  layers  and  large  masses,  which  often  run  off'  into  veins  across  the 
schists,  of  a  granitoid  mixture  of  quartz,  little  feldspar,  and  much  green  biotite 


THE  PELHAM-SMUTESBUllY  SYNCLINE.  225 

(rarely  brown)  in  large  scales  which  are  completely  filled  with  radiating 
tufts  of  fibrolite. 

The  schists  contain  graphite  abundantly  disseminated  in  small  scales, 
often  hexagonal,  and  some  layers  are  finely  colored  masses  of  purple,  almost 
amethystine  garnet,  pyrite  and  apatite  in  distinct  crystals. 

The  orthoclase  t)f  the  granite  is  now  in  every  stage  of  change  into  an 
amorphous  mineral;  Hzzl;  color,  pale  mountain-green  to  deep  olive-green, 
or  light  to  dark  wax-yellow.  The  yellow  is  translucent  on  edges,  and  this 
increases  in  water.  In  the  flame  the  green  mineral  rapidly  becomes  white. 
The  yellow  variety  becomes  flesh-colored,  like  a  decomposed  feld-spar. 
Both  give  a  fine  blue  with  cobalt,  and  fuse  at  3  to  4  to  white  enamel.  The 
fibrolite  is  also  often  attacked  in  the  same  way,  the  change  proceeding  from 
the  centers  of  radiation  of  the  needles,  which  are  first  beaded  with  browner 
spots,  showing  aggregate  polarization,  and  then  wholly  changed,  and  at 
last  involving  the  biotite  also,  while  the  garnet  is  the  last  to  be  afi"ected. 
The  quartz  clears  up  under  the  blowpipe  and  efi'ervesces  with  soda. 

The  quartz,  through  all  the  adjoining  schist  and  granite,  is  of  the  same 
waxy  luster  as  the  amorphous  mineral,  and  has  become  brittle  (H^4), 
and  gives  with  cobalt  a  beautiful,  filmy,  superficial  blue,  deeper  in  spots. 

The  change  seems  to  be  initiated  by  the  decomposition  of  the  pyrite, 
and  it  seems  possible  that  the  curious  appearance  of  the  quartz  is  due  to 
hydi'ofluoric  acid  set  free  from  the  micas  during  their  decomposition,  but  it 
is  at  times  a  deeper  change  into  an  aluminous  silicate. 

The  topographical  surroundings  of  this  interesting  locality  are  such  as 
to  render  it  probable  that  the  Trias  conglomerate  was  barely  planed  off 
from  its  surface  during  the  Glacial  period,  so  that  it  is  a  remnant  of  an 
ancient  and  peculiar  form  of  decomposition  which  took  place  beneath  the 
conglomerate. 

THE  PELHAM-SHUTBSBURY  SYNCLINE. 

Across  Pelham  the  great  block  of  Monson  gneiss  (a)  which  occupies 
the  whole  town  is  nearly  horizontal,  with  low  dip  to  the  east  on  the  east 
side  and  to  the  west  on  the  west  side.  On  the  east  side  of  this  extremely 
flat  anticline  we  have,  commencing  with  the  central  (that  is,  the  lowest) 
beds  at  the  quarries  in  the  center  of  Pelham,  the  true  friable  subporphyritic 

MON  XXIX 15 


226       GEOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 

biotite-gneisses  (a);  then,  at  and  just  east  of  East  Pelham,  the  actinoHte 
quartzite;  then  a  second  narrow  band  of  the  biotite-gneiss  (a);  then  a  broad 
band  of  the  muscovite-  (&)  and  hornblende-  (d)  schist  here  discussed;  and 
finally,  at  top,  a  recurrence  of  the  true  biotite-gneiss  (a)} 

On  the  east  the  series  dips  with  so  small  an  angle  and  so  regularly 
eastward,  and  the  members  can  be  seen  passing  under  each  other  so 
normally,  that  it  is  very  difficult  to  avoid  the  conclusion  that  they  are  in 
regular  succession  and  that  all  are  a  part  of  the  Monson  gneiss  sei'ies,  and 
this  was  at  first  my  opinion.  On  the  other  hand,  the  series  bears  in  several 
particulars  strong  resemblance  to  the  mica-schists  and  amphibolite  as  devel- 
oped to  the  east  in  New  Salem. 

As  one  goes  down  the  long  hill  east  from  Pelham  Center,  after  reach- 
ing the  first  road  tui'ning  south,  one  finds  many  outcrops  of  a  thin-fissile, 
quartzose  two-mica-gneiss,  which  varies  from  a  thin-fissile  quartzite  with 
much  coarse  muscovite  spread  upon  the  rather  distant  foliation  faces  to  a 
fissile  biotite-gneiss  with  muscovite  distributed  as  above,  or,  finally,  a  shin- 
ing-white, purely  muscovite-gneiss,  or — and  this  last  comes  to  be  the 
prevailing  rock  going  either  north  or  south — a  very  coarse,  rather  rusty 
miuscovite-biotite-gneiss  or  schist.  This  agrees  closely  with  the  basal 
beds  (V)  of  the  other  section.  Slight  traces  of  the  hornblendic  rock  (d) 
occur  down  this  slope,  but  northward,  across  Purgee's  brook,  a  heavy  bed 
of  the  hornblendic  rock  {d?)  appears  in  the  bluff  north  of  D.  Shore's  house. 

The  series  can  be  followed  from  this  section  south  5  miles  to  a  point 
west  of  Enfield  Center  and  north  5  miles  across  Pelham  and  Shutesbury 
into  Wendell,  maintaining  a  width  of  about  a  mile,  which,  from  the  low 
dip  and  its  position  on  a  hillside  sloping  with  the  dip,  does  not  represent  a 
great  thickness  In  all  this  distance  the  rock  is  everywhere  cut  by  great 
granite  dikes  or  is  greatly  impregnated  with  granite,  so  that  many  beds 
seem  like  piu-ely  granitic  (pegmatitic)  material  made  schistose  by  pressure. 

Above  the  amphibolite  (<i)  in  the  above  section  and  near  D.  Shore's  house 
a  coarse  mica-schist  full  of  large  garnets  represents  the  Savoy  schist  (e),  and 
following  the  river  road  north  from  this  point  any  section  carried  across  the 
hills  to  the  west  would  give  the  same  succession  until,  in  the  extreme  north- 
east corner  of  Pelham,  one  finds  these  upper  schists  dipping  apparently 
beneath  the  heavy-bedded  Monson  gneiss,  but  separated  from  it,  I  suppose, 

'  The  italic  letters  refer  to  sections  given  on  pp.  213-214. 


THE  GKEAT  OENTEAL  SYNCLINE.  227 

by  a  fault  which  the  exposures  did  not  permit  me  to  demonstrate.  This 
continues  north  into  Shutesbury,  where  the  whole  series  is  cut  by  a  trans- 
verse fault,  along  which  trap  has  been  erupted  in  sevei-al  places.  North  of 
this  point  the  series  seems  to  be  a  regular  overturned  syncline.  The  bed 
above  the  amphibolite  (d)  appearing  in  the  center  is  a  thin-bedded  quartz- 
ite  (h)  with  few  coarse  muscovite  scales,  but  it  soon  runs  out,  as  does  the 
amphibolite,  while  a  narrow  band  of  the  coarse  muscovite-schist  (e)  runs  a 
long  way  north,  past  the  mineral  springs  and  far  into  Wendell. 

Followed  south  the  three  beds  already  described  soon  dip  beneath  a 
dark  mica-schist  containing  much  biotite  and,  at  school  No.  6  in  Enfield, 
many  small  needles  of  dark-brown  tourmaline  and  a  little  feldspar.  This 
I  have  referred  to  the  Conway  schist  (/). 

This  series  runs  S.  15°  E.,  and  so  abuts  with  very  acute  angle  upon 
the  fault  which  runs  along  the  east  side  of  the  valley  of  Swift  River  Branch. 
It  is,  if  my  interpretation  as  given  upon  the  map  be  true,  a  syncline  over- 
turned to  the  west,  and  to  the  south  of  the  transverse  fault  near  the  north 
line  of  Pelham  is  further  affected  by  a  longitudinal  fault  which  eliminates 
part  of  the  east  flank  of  the  fold. 

THE  GREAT  CENTRAL  SYNCLINE. 

This  enters  the  State  from  New  Hampshire,  occupying  the  whole  east- 
em  half  of  the  town  of  Warwick  and  extending  eastward  into  Royalston  a 
mile  beyond  the  limits  of  the  area  shown  on  the  map  (PI.  XXXIV). 

West  of  TuUyville,  in  the  apex  of  the  town  of  Orange,  it  divides, 
sending  off  an  eastern  branch  (see  p.  234),  and  itself  extends  south  with 
diminished  width. 

WARWICK   AND   ORANGE. 

The  western  quartsites  and  amphiholites. — For  a  long  distance  south  the 
syncline  consists  of  a  broad  area  of  mica-schists,  having  on  either  side  a  nar- 
row border  of  the  quartzite  beds  (b)  below,  which  separate  the  schists  from 
the  Monson  gneiss  on  the  east  and  on  the  west.  Where  they  enter  the  State 
in  the  eastern  hillside  above  Sunny  Valley,  in  the  northern  part  of  Warwick, 
the  basal  bed  is  a  white,  shining  muscovite-quartzite,  often  gneissoid,  and 
south  of  Warwick  village  it  is  a  coarse,  gneissoid  quartzite,  containing  much 
chlorite  and  magnetite. 


228  GEOLOGY  OP  OLD  HAMPSHIEE  COUNTY,  MASS. 

The  amphibolite  (d)  is  a  thin-fissile,  often  epidotic,  persistent  bed,  not  of 
great  thickness,  which  on  Mount  Grace  contains  a  beautiful  radiated  tour- 
maline, common  in  collections, 
t  , 

The  upper  quartzite  bed  (e)  is  developed  as  a  light,  sandy  biotite-schist 
(—  whetstone-schist)  for  a  long  distance  east  of  the  road  east  of  Sunny 
Valley.  Northeast  of  Warwick  Center  it  is  a  thin-bedded  quartzite,  exactly 
like  the  Bernardston  quartzite.     It  is  generally  a  gray  whetstone-schist. 

These  three  beds  dip  east  beneath,  and  form  a  narrow  border  to,  the 
great  area  of  mica-schist  (/),  which  has  a  width  eastward  of  nearly  4  miles. 

Structure. — The  lower  beds  dip  east  beneath  the  mica-schist.  The 
latter  strikes  north-south  and  has  high  and  irregular  dips,  being  crumpled 
up  into  a  mass  from  which  one  can  gain  no  idea  of  its  real  thickness. 

The  lower  beds  run  south  normally  until,  opposite  Mount  Grace,  they 
are  thrown  into  great  confusion.  An  east- west  fault  runs  through  the  north 
brow  of  the  mountain  and  far  east.  South  of  this  and  on  the  slope  east  of 
Mount  Grace  the  lower  beds  are  greatly  crumpled,  while  Mount  Grace 
itself  is  formed  by  the  westward  projection  and  folding  of  these  three  beds, 
and  traces  of  this  disturbance  are  seen  all  through  the  village  of  Warwick, 
the  rocks  being  so  crumpled  that  the  amphibolite  runs  south  in  three  long 
bands  to  Basting's  pond.  On  this  bend  north  of  the  pond  a  vein  of  coarse 
epidote-garuet  rock  with  fine  quartz  crystals  is  found 

Farther  on  the  lower  beds  regain  their  regular  posture  and  run  south 
to  Harris's  pond,  in  the  southwest  corner  of  the  town,  where  the  Wendell 
anticline,  already  described  (p.  217"),  branches  off".  A  little  to  the  east  a 
minor  fold  brings  up  the  amphibolite  {(£)  through  the  mica-schist  (/),  and  on 
either  side  of  it  the  whetstone-schist  (e),  in  a  narrow  anticline  which  runs 
down  Brush  Valley,  crosses  the  river  east  of  West  Orange  and  continues 
south,  ending  in  the  west  part  of  Orange. 

The  eastern  harder  of  quartsites  and  amphiholites. — At  the  east  side  of 
Prospect  street,  in  Orange,  the  amphibolite  (d)  rests  directly  against  the 
Monson  gneiss,  with  steep  eastward  dip,  as  if  it  went  under  the  latter.  This 
"fan  structure"  is  common  all  around  the  Orange  basin. 

The  beds  below  the  amphibolite  are  faulted  out  of  sight — north  and 
south — for  a  long  distance.  The  latter  is  reduced  to  a  small  thickness  here, 
perhaps  30  feet;  and  the  upper  quartzite  (e)  is  still  more  reduced,  being  here 
a  compact  quartzite ;  a  mile  north  it  is  a  fine-grained  micaceous  quartzite. 


THE  GREAT  CENTRAL  SYNCLINE.  229 

The  central  fihrolitic  mica-schists  (the  Conway  schists). — These  are  dark, 
nisty,  contorted  muscovite-biotite-schists,  at  times  spangled  with  transverse 
biotite.  They  contain  garnets,  often  in  large  numbers,  of  small  size  and  of 
the  form  oo  0  (110).  Staurolite  appears  rather  rarely,  but  at  localities 
scattered  over  all  the  area,  especially  on  the  west,  where  the  Wendell 
syncline  branches  oif ;  and  across  to  the  east,  where  the  road  north  from 
Tullyville  crosses  the  town  line,  the  rock  is  a  rather  coarse  mica-schist, 
the  matrix  made  iip  of  fine  scales  of  shining-white  muscovite,  but  largely 
darkened  by  graphite  and  by  large  blotches  of  biotite.  It  contains  garnets 
and  large  single  staurolites,  together  with  fibrolite. 

Fihrolite  in  the  mica-schists. — This  mineral  occurs  in  the  mica-schist  a 
mile  northeast  of  Warwick  Center,  south  of  the  house  of  Rev.  J.  Groldsbury. 
If  a  line  be  di-awn  southeast  from  this  point  to  the  apex  of  Orange,  at  the 
locality  just  mentioned,  above  Tullyville,  it  will  mark  approximately  the 
northern  border  of  the  abundant  occurrence  of  the  mineral  in  the  schists.  If 
another  line  be  drawn  south  from  the  same  point  it  will  mark  the  westei'n 
boundary  of  the  occurrence  of  fibrolite  through  Warwick  and  Orange.  From 
these  boundaries  it  gradually  increases  in  amount  southwardly  and  east- 
wardly,  but  the  increase  is  more  marked  toward  the  east  than  toward  the 
south,  so  that  the  eastern  syncline  from  its  beginning  in  Tullyville  is  marked 
by  a  maximum  of  the  mineral,  which  continues  clear  across  the  State.  It 
is  not  abundant  in  Warwick,  nor  southward  in  the  central  syncline  here 
described,  through  Orange.  The  transition  is  indicated  on  the  map  (PI. 
XXXIV)  by  allowing  the  Conway  schist  color  to  grade  into  the  Brimfield 
fibrolite-schist  color  without  drawing  a  boundary  line  across  the  strike. 
This  is  the  most  important  illustration  of  the  passage  of  the  Conway  schist 
into  the  Brimfield  fibrolite-schist. 

To  the  east  of  the  center  of  the  area  of  mica-schist  occurs  a  band  of 
amphibolite,  generally  porphyritic  in  appearance,  the  structure  being  due 
to  the  absence  of  hornblende  from  spots  which  thus  appear  white.  In  this 
amphibolite  band  is  much  iron,  especially  a  half  mile  west  of  the  point  where 
the  Warwick-Orange  road  crosses  the  town  line.  Here  a  small  amount  of 
mining  work  has  been  done.  The  mine  is  opened  2  rods  on  the  "vein"  and 
10  feet  deep.  The  "vein"  is  a  vertical  bed  of  quartz-garnet  rock,  very 
ferruginous,  1  foot  wide  at  north  end  and  3  feet  wide  at  south  end,  with  a 
central  layer  of  very  compact,  pure  magnetite  4  to  6  inches  thick. 


230       GEOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 


TOPOGEAPHY. 


The  mica-schist,  when  set  on  edge,  is  usually  the  more  durable  rock, 
and  appears  in  the  row  of  hills — Mallards  Hill,  Beech  Hill,  Pitts  Hill,  Fall 
Hill — which  sharply  border  the  gneiss  depression  of  North  Orange;  and 
where  the  central  anticline  brings  up  the  amphibolite  and  whetstone  it 
produces  the  "Brush  Valley,"  and  the  mica-schists,  divaricating  on  the  west 
from  the  main  body,  formed  the  long  ridge  of  Barbers  Hill.  At  the  same 
time  the  quartzites,  sharply  folded  and  compacted  with  granite,  rise  high 
above  the  level  of  these  hills  in  Mount  Grrace.  On  the  other  hand,  in  the 
next  anticline  to  the  east  the  "Big  Tully  Mountain,"  made  of  granite,  rises 
to  a  peak  which  dominates  the  whole  region.  The  Swift  River  fault  runs 
between  these  two  basins,  and  some  comparatively  modern  elevation  may 
explain  the  discrepancy. 

SOUTH  ORANGE  AND  NEW  SALEM. 

The  tvestern  border. — The  western-border  beds  cross  the  river  east  of 
West  Orange  and  go  south  down  the  west  line  of  Orange,  crossing  the 
corner  of  Wendell  and  continuing  south  along  the  New  Salem-Shutesbury 
line,  where  they  become  involved  in  the  West  Branch  fault. 

The  following  section  across  the  middle  of  this  town  Hne,  from  the 
schoolhouse  in  the  west  edge  of  Shutesbury,  gives  the  succession  of  all 
the  strata,  including  the  mica-schist : 

Section  in  Shutesbury. 

Feet. 

1.  Monson  gneiss  (a) 

2.  Granular,  micaceous  quartzite  (Eowe)  (b) 100 

3.  Amphibolite  (Chester)  {d) 100 

4.  Rusty,  contorted,  chloritic  sericite- schist  (Savoy)  (e) 325 

5.  Amphibolite 16 

6.  Dark-gray,  spangled  mica-schist  (Conway)  (/)  - 

The  latter  bed  is  graphitic,  garnet-bearing,  contains  transverse  biotite 
scales,  and  is  identical  with  the  Conway  schists.  It  includes  a  single  bed  of 
thin-fissile  quartzite,  consisting  of  a  limpid  quartz  like  that  of  a  mineral  vein. 

This  border  series  seems  to  meet  the  fault  line  at  a  very  acute 
angle,  so  that  in  the  hill  just  north  of  Cooleyville  the  lower  member  of 
the  section  above  is   cut  out  and  the  amphibolite  (d)  abuts   against  the 


THE  GKEAT  CENTRAL  SYNOLINE.  231 

Monson  gneiss  (a).  The  latter  indurated  the  former  and  shattei'ed  it,  and  a 
heavy  bed  of  granitic  fault  I'ock  (flesh-colored  binary  granite)  is  interposed. 
Just  sovith  of  Cooleyville,  at  the  last  house  before  the  road  crosses  the  Pres- 
cott  line,  is  an  interesting  section:  Below  is  Monson  gneiss  (a),  flat-foliated 
but  thick-bedded,  regularly  spotted  by  grains  of  black  hornblende,  and 
looking  like  a  granite-porphyiy,  being  much  more  compact  and  less  granu- 
lar than  usual,  and  plainl}^  influenced  by  the  fault.  The  great  fault  up  the 
hillside  is  marked  by  about  25  feet  of  a  granitic  fault  rock,  at  times  a  flesh- 
colored  binary  granite,  at  times  a  hornstone  of  similar  color  or  green,  at  times 
a  flesh-colored  chloritic  gneiss  in  sti'ucture — all  these  crushed  and  recrushed 
and  again  cemented.  Then  comes  about  10  or  15  feet  of  amphibolite  (d), 
also  wholly  crushed,  and  above  this  a  buff"  quartzite,  perhaps  20  feet  thick, 
followed  by  a  great  thickness  of  bedded  gneissoid  rock,  granular  and  rusty, 
and  with  its  micaceous  mineral  wholly  decomposed,  which  is  apparently 
identical  with  the  chloritic  sericite-schist  (e)  of  the  last  section  but  one. 
It  repeats  exactly  the  corresponding  members  of  the  section  north  of 
Cooleyville,  and  this  shows  that  nearly  all  the  amphibolite  has  here  been 
cut  off"  on  the  fault. 

The  eastern  border  beds. — At  Orange  Center  the  border  beds  are  com- 
pressed against  the  gneiss  and  overturned,  the  lowest  bed  wholly  concealed, 
the  others  greatly  thinned.  Just  south  of  the  river  in  "Walnut  Hill  all  these 
beds  reappear  in  force  and  in  duplicate  in  a  remarkable  subordinate  anti- 
cline, best  understood  by  inspection  of  the  map  (PI.  XXXIV). 

The  whole  center  of  the  hill  is  made  up  of  the  lower  member,  here 
a  fine-grained,  thin-fissile,  two-mica  gneissoid  quartzite  (&),  with  garnets. 
This  is  flanked  on  either  side  by  amphibolite  (d),  then  by  a  micaceous 
quartzite  (e),  then  by  the  mica-schist  (/),  which  is  on  the  east  side  fibrolitic. 

The  narrow  syncline  which  separates  this  anticline  from  the  gneiss  on 
the  east  dies  out  southward  and,  a  little  over  the  south  line  of  Orange,  lets 
the  basal  member  of  the  series  come  in  contact  with  the  Monson  gneiss  in  a 
normal  manner,  and  it  continues  thus  across  New  Salem  as  a  broad  band  of 
two-mica  quartzose  gneiss. 

The  mica-schist. — This  has  been  described  in  the  section  above  as  a 
true  graphitic,  spangled  Conway  schist.  This  is  its  character  only  in  a 
narrow  band  along  the  New  Salem-Shutesbury  line,  which  runs  out  before 
reaching  the  latitude  of  Cooleyville  on  the  south,  and  which  on  the  north 


232  GEOLOGY  OF  OLD  HAMPSHIEE  OOUNTT,  MASS. 

soon  merges  into  the  coarser,  less  grapliitic,  rusty,  garnetiferous  schists 
common  farther  north. 

Around  New  Salem  Center  it  is  greatly  cut  by  granite  and  carries 
several  bands  of  amphibolite,  and  bowlders  of  a  pyroxene-garnet  rock 
occur,  which  indicate  the  former  presence  of  limestone.  All  this  area  of 
the  schist,  except  as  mentioned  above,  lies  to  the  west  of  the  line  already 
given  as  the  boundary  of  the  occurrence  of  fibrolite,  and  this  mineral  was 
not  observed  at  all  in  New  Salem ;  but  the  band  of  mica-schist  which  runs 
down  from  New  Salem  village  carries  this  mineral  soon  after  it  passes  over 
into  Prescott. 

Structure. — An  inspection  of  the  map  will  show  that  the  band  crosses 
the  north  line  of  New  Salem,  after  disengaging  itself  from  the  Walnut  Hill 
anticline,  as  a  simple  syncline,  and  continues  thus  to  the  middle  of  the 
town,  where  an  upfolding  of  the  whetstone-schists  (e)  separates  the  mica- 
schists  (/)  into  two  parts,  and  a  little  farther  south  this  upfolding  brings 
up  also  the  amphibolite  (d),  which  runs  down  to  the  east  of  the  large 
diorite  area  and  seems  to  end  upon  an  eastward  prolongation  of  the  great 
Pelham  cross-fault,  and  I  have  so  represented  it. 

The  western  and  broader  portion  into  which  the  mica-schist  (/)  is  thiis 
divided  contracts  rapidly  and  sends  a  narrow  lobe  down  west  of  the  dio- 
rite mass  into  Prescott,  where  it  ends.  All  these  irregularities  stand  in 
relation  to  this  great  mass  of  diorite,  as  appears  plainly  from  an  inspection 
of  the  map,  and  prove  that  it  was  present  passively  during  the  upfolding  of 
the  rocks,  preventing  the  continuance  southward  of  the  regular  syncline 
in  New  Salem  already  described.  Indeed,  a  further  irregularity  appears 
east  of  the  north  end  of  this  diorite  mass,  in  that  the  three  lower  members 
of  the  series  disappear,  and  the  mica-schists  can  be  for  a  long  distance  seen 
resting  directly  upon  the  gneiss  to  the  east. 

PRESCOTT  AND  ENFIELD. 
STRUCTURE. 

Across  Prescott  the  band  continues  unchanged.  It  is  bordered  on  the 
east  and  the  west  by  faults  which  separate  it  from  the  Monson  gneiss  (a) 
and  conceal  the  two  lower  beds.  The  surface  is  thus  mostly  occupied  by 
the  whetstone-schists  (e — Savoy  schist),  the   amphibolite  (d)  coming  up 


THE  GREAT  CENTRAL  SYNCLINE.  233 

throuffh  these  near  their  western  border,  and  a  broad  band  of  the  mica- 
schists  (/)  sepai'atiug  them  from  the  gneiss  on  the  east. 

As  they  pass  into  Enfield  both  these  faults  become  less  effective  On 
the  west  the  Monson  g-neiss  is  no  longer  brought  up  to  form  the  western 
border  of  the  band  of  schists,  but  these  are  permitted  to  come  into  normal 
relations  with  the  Pelham  band  beneath  the  sands  of  the  West  Branch,  the 
two  forming  a  double  syncline  of  much  regularity.  The  fault,  however, 
seems  to  continue  due  south  across  the  whetstone-schists,  directly  toward 
Enfield  village,  and  it  is  marked  north  of  this  village  by  a  line  of  crushed 
rock  full  of  comby  quartz,  which  runs  down  west  of  the  amphibolite  and 
between  the  two  roads  running  north  from  the  village,  near  the  house  of 
J..  Thayer.  On  the  east  the  amphibolite  (d)  appears  again,  and  toward 
the  southern  part  of  Enfield  the  Rowe  two-mica-gneiss  (&)  also  comes  up 
from  below  the  latter. 

At  this  point  the  band  comes  under  the  influence  of  the  Belchertown 
tonalite  and  passes  down  its  eastern  border,  through  Ware  and  Palmer, 
greatly  faulted  and  metamorphosed,  so  that  its  description  is  connected  with 
the  discussion  of  the  contact  metamorphism  effected  by  the  tonalite  (p.  243). 

South  of  this  it  becomes  the  West  Monson  syncline,  which  is  more 
naturally  associated  with  the  other  bands  east  and  west  of  it  and  is  discussed 
in  a  later  section  of  this  chapter  (p.  249). 

PETEOGKAPHICAL    DESCRIPTIONS. 

The  basal  bed  of  the  series  (Rowe)  is  wanting  through  nearly  the 
whole  area.  Where  it  reappears,  in  the  south  part  of  Enfield  and  Ware,  it 
is  a  coarse  muscovite-gneiss,  as  in  Pelham.  The  amphibolite  requires  no 
special  description.  The  whetstone-schist  (Savoy),  usually  a  gray  whet- 
stone, becomes  in  North  Prescott,  near  H.  Stetson's,  a  flat-fissile  sericite- 
schist  with  large  garnets  (15-20""),  which  change  externally  into  coarse 
chlorite.  It  corresponds  exactly  with  the  same  rock  west  of  the  river — the 
typical  Savoy  sericite-schist — with  which  it  is  here  paralleled.  Farther 
south,  near  A.  Gilbert's,  it  becomes  a  snow-white  quartzite  divided  by  very 
broad,  whitish  (sericite)  films. 

In  Enfield,  north  of  School  No.  4,  it  is  the  same  as  above,  but  very 
greatly  contorted.  In  the  soiith  of  Enfield,  on  the  east  flank  of  Quabin 
Mountain,  it  appears  in  great  force  as  a  snow-white,  granular  quartzite, 


234  GEOLOGY  OP  OLD  HAMPSHIRE  COUNTY,  MASS. 

with  few  distant  films  of  white  muscovite,  which  was  recommended  bj 
President  Hitchcock  as  a  firestone  for  furnaces. 

Farther  south,  in  Palmer  (north  of  Gr  Keith's),  it  is  again  a  greatly 
crumpled,  white,  granular  quartzite  with  distant  sericite  films;  and  still 
farther  south,  on  the  west  flank  of  the  high  hill  above  Thorndike  (north 
of  C.  Kalliher's),  it  is  a  curious  white  sericite-  or  hydromica-schist ;  broad, 
continuous  wavy  sheets  of  pea-green  hydi'ated  mica  inclose  flattened, 
nodular  masses  of  friable  quartz  resembling  loaf  sugar. 

The  band  of  mica-schist  (/)  which,  starting  at  New  Salem  Center, 
runs  down  the  east  side  of  Prescott,  becomes  gradually  more  fibrolitic  and 
extends  across  Enfield,  Ware,  and  Palmer  as  a  rusty,  graphitic,  corrugated 
schist,  generally  coarse  and  carrying  few  garnets.  The  fibrolite  remains 
very  fine  and  is  not  abundant,  and  the  "augen"  of  transparent  feldspar 
found  in  the  next  band  to  the  east  are  wanting. 

THE  EASTERIS^   SYNCLINE. 
ORANGE   AND  ATHOL. 
GENERAL    DESCRIPTION. 

Where  it  branches  from  the  broad  central  syncline  in  the  northeast 
corner  of  Orange  and  crosses  the  town  the  band  of  the  schist  forms  a  high 
ridge  looking  down  upon  the  granite  basin  of  the  Tully  brooks  on  the  east 
and  upon  the  gneiss  basin  of  Orange  Center  on  the  west.  It  is  a  closed  syn- 
cline with  a  subordinate  central  anticline,  all  slightly  overturned  toward 
the  east.  Along  the  western  slope  the  western  wing  of  the  syncline  is 
abundantly  exposed.  The  center  and  eastern  wings  are  almost  continuously 
laid  bare  along  the  road  which  forms  the  boundary  between  Orange  and 
Athol  and  on  its  continuation  toward  Athol. 

The  Monson  gneiss,  which  appears  low  down  on  the  western  slope 
opposite  J.  Worrick's,  is  a  stretched,  slightly  epidotic  biotite-gneiss.  It  is 
subporphyritic  by  the  development  of  shapeless,  opaque,  white  feldspar 
clumps. 

Next  above  is  a  heavy  bed,  occupying  the  whole  hillside,  of  a  rather 
coarse  poi^phyritic  gneiss,  or  augen-gneiss,  which  over  a  large  area  is  not 
very  different  from  the  lower  gneiss  on  superficial  examination.  When 
studied  carefully,  however,  it  is  found  to  be  very  different.  The  feldspar, 
instead  of  being  opaque,  has  a  moonstone-like  transparency,  which  con- 


Tin-:  EASTERN  SYNGLINE.  235 

tiuues  to  bo  a  characteristic  of  the  gueissoid  members  of  this  fibrolitic 
series  clear  across  the  State.  The  feldspars  are  also  often  in  regularly 
shaped  carlsbad  twins.     Tlie  rock  is  a  complete  augen-gneiss. 

Continuous  micaceous  films  or  sheets  of  varying-  thickness,  while  in 
general  parallel  to  one  another,  wind  in  and  out  and  inclose  the  quartz-feld- 
spar nodules  or  the  larger  porphyritic  crystals,  and  these  sheets  are  thin 
layers  of  a  strongly  fibrolitic  biotite-muscovite-schist,  which  can  be  traced 
in  one  direction  to  where  it  is  lost  in  thin  films  in  local  granitic  masses  and 
in  the  other  to  where  the  sheets  coalesce  in  heavy  beds  of  slightly  feld- 
spathic  fibrolite-schist.  Corresponding  with  the  stronger  metamorphism, 
the  fibrolite  is  unusually  coarse  for  the  region,  occurring  in  distinct  trans- 
parent needles  and  not  in  the  fine-fibrous  bucholzite. 

I  have  little  doubt  that  this  is  a  case  of  extreme  granitic  impregna- 
tion and  regular  insinuation  of  the  granitic  material  between  the  opened 
laminse  of  the  schist  subsequent  to  its  formation  as  a  schist,  and  that 
the  rock  is  the  representative  of  the  layer  between  the  biotite-gneiss 
(a — Monson  gneiss)  and  the  amphibolite  (d)  in  the  other  bands,  where  it  is 
so  often  developed  as  a  two-mica-gneiss.  The  band  is  here  about  820  feet 
thick.  It  is  thus  placed  as  the  equivalent  of  the  Rowe  schist,  though 
the  development  of  fibrolite  in  these  lower  beds  is  exceptional. 

Next  above  comes  the  amphibolite,  very  coarsely  crystalline  and  por- 
phyritic in  its  lower  band  and  carrying  beds  of  a  finely  matted,  fibrous, 
dull,  dark-gray  hornblende  rock.     It  is  about  650  feet  thick. 

Intercalated  with  the  amphibolite  and  forming  a  thin  bed  above  it  is  a 
rusty,  very  arenaceous  biotite-schist  of  rather  fine  grain,  which  lacks  fissility 
but  agrees  quite  well  with  the  whetstone-schist  of  the  Northfield  series. 

Above  this  comes  a  great  thickness  of  the  coarse,  very  rusty  mus- 
covite-biotite-schists,  in  places  very  fibrolitic,  the  fine-fibrous  mineral 
(fazerkiesel,  bucholzite)  occurring  in  films  or  in  regularly  disseminated 
porphyritic  blotches,  whose  shape  and  aiTangement  are  so  like  those  of  the 
blotches  of  muscovite  common  in  these  schists  as  to  suggest  the  derivation 
of  the  fibrolite  from  the  muscovite.  Two  things  are  certain,  that  the 
fibrolite  is  closely  associated  with  the  muscovite,  and  that  its  amount 
inci'eases  with  the  increasing  intensity  of  the  metamorphism,  as  is  best  seen 
in  the  abundance  and  lai'ge  size  of  the  mineral  in  the  contact  ring  of  the 
tonalite  in  Belchertown. 


236  GEOLOG-Y  OF  OLD  HAMPSHIRE  COUNTY,  MASS, 


In  the  center  of  the  area  the  amphiboHte  is  brought  up  along  the  south 
hne  of  the  town,  as  it  seems  to  me,  by  a  minor  fold.  It  may  be  traced 
north  nearly  to  North  Orange.  On  the  east  of  the  anticline  the  amphibolite 
appears  in  force  at  the  third  bend  after  passing  the  site  of  the  old  fort  on 
the  road  to  Athol. 

The  beds  above  the  amphibolite,  which  represent  the  whetstone-schist, 
are  a  fine-grained  biotite-quartzite,  having  some  resemblance  to  very  fine- 
grained varieties  of  the  lower  gneiss.  Northward  along  the  eastern  border 
the  lower  beds  are  everywhere  covered  by  the  broad  gravels  of  the  valley. 

METAMOEPHISM    OF    THE   AMPHIBOLITE   BAND   AS    IT    IS    INVOLVED   IN  THE    GEAN- 
ITITE    OF   THE   ATHOL    BATHOLITE,  AND    ITS    LATEE    CHANGE    TO    STEATITE. 

The  great  bed  of  amphibolite  which  occurs  east  of  Athol,  and  which 
is  in  one  place  changed  to  steatite,  can  be  followed  a  long  way  N.  20°  W., 
and  after  disappearing  for  a  distance  beneath  the  sands  it  appears  again  in 
the  southwest  shoulder  of  Tullys  Mountain,  east  of  North  Orange,  crosses 
the  great  granitite  mass  like  a  bridge,  and  is  continued  beyond  in  the 
schists,  changing  with  their  strike  to  the  northeast.  It  mounts  the  steep 
granite  mountain  side  with  a  width  of  about  40  rods,  and  is  well  exposed 
by  the  workings  of  the  soapstone  quarry.  The  adjoining  granitite  is  a 
fine-grained  biotite-granite,  containing  rarely  large  crystals  of  magnetite 
and  a  little  allanite.  It  shows  a  slight  banding  parallel  to  the  contact  with 
the  schist,  and  sends  offshoots  into  the  latter 

At  the  quarry  the  contact  for  a  long  distance  runs  athwart  the  folia  of 
the  schists,  and  their  twisted  ends  abut  against  the  granitite  and  are  parted 
by  it.  The  great  mass  of  the  hornblende-schist  is  changed  into  a  coarse, 
shining,  dark-brown,  massive  gedrite^  rock,  containing  small,  fresh  plagio- 
clase  grains,  and  abounding  in  small,  sharp  cubes  of  pyrite  with  truncated 
corners,  or  a  more  friable  dark-green  aggregate  of  actinolite  needles.  In 
part,  especially  near  the  borders,  the  rock  retains  the  banded  appearance 
which  it  has  beyond  the  limits  of  the  granitite.  All  the  contact  phenomena 
are  those  of  an  eruptive  rock  upon  a  schist.  In  several  places  the  massive 
gedrite  rock  is  further  changed,  in  bands  running  about  N.  70°  E.,  into  a 
dark-green  soapstone  abounding  in  white  dolomite,  talc,  and  a  green  chloritic 
mineral.     In  some  places  there  are,  over  broad  surfaces,  plates  of  clinochlore 

'  For  description  and  analysis  see  "Gedrite  "  in  A  miueralogical  lexicon :  Bull.  U.  S.  Geol.  Sui-vey 
No.  126,  1895,  p.  86.     By  mistake  the  mineral  is  assigned  to  Warwick  instead  of  Orange. 


THE  EASTERN  SYNCLINE.  237 

seviTiil  inches  across.  The  steatite  did  not  appear  to  be,  either  in  character  or 
amount,  of  economic  importance.  This  seems  to  be  a  case  similar  to  many 
I  liave  studied  among  the  great  granite  ovals  in  Massachusetts,  where  the 
i<i-neous  rock  has  forced  its  way  upward  through  the  compressed  schists, 
dissolving  or  parting  them  in  its  progress,  so  that  the  present  erosion  sur- 
face often  presents  an  appearance  as  if  the  great  separate  floes  of  the  schist 
had  floated  upon  the  granite  while  still  held  in  orientation  with  the  sur- 
rounding schists.  They  bear  testimony  to  the  continuity  of  the  overlying 
schists  which  once  covered  the  granite  and  projected  into  it,  and  they  owe 
their  common  dip  and  strike  to  this  former  connection. 

WARE. 
GENERAL    BESCEIPTION. 

The  eastern  band  of  schists  leaves  the  county  at  the  south  line  of 
Orange,  and,  traversing  Worcester  County  for  a  long  distance,  reenters  the 
area  of  the  map  in  Ware  and  crosses  Palmer  and  Monson.  The  fourfold 
division  of  the  schists,  which  has  been  persistent  over  so  large  an  area,  and 
which  seems  to  be  somewhat  less  distinct  at  the  beginning  of  this  band  in 
Orange,  here  fails  entirely.  It  is  reduced  to  a  twofold  division  of  amphib- 
olites  below,  resting  directly  upon  the  Monson  gneiss,  and  a  great  volume 
of  fibrolitic  mica-schists,  the  lower  portion  of  which  may  represent  the 
whetstone-schist,  but  in  which  no  persistent  lithological  distinctions  can  be 
established. 

On  the  map  I  have  given  to  this  band  a  color  resembling  that  given  to 
the  Conway  mica-schist,  since  in  Orange  and  Warwick  the  gradual  passage 
of  schists  whicb  are  lithologically  and  stratigraphically  the  representative 
of  this  terrane  into  these  fibrolite-schists  can  be  clearly  followed,  and  the 
lessening  of  the  number  of  distinct  bands  above  the  amphibolite  seems  to 
be  efiected  mainly  by  the  suppression  of  the  whetstone-schist  or  its  merging 
with  the  hornblende-schist,  with  which  it  seems  more  intimately  connected 
than  with  the  upper  bed,  rather  than  by  its  becoming  lithologically  like  this 
upper  bed — that  is,  like  the  Conway  mica-schist. 

Across  Ware  the  amphibolite  can  be  followed  with  apparent  continuity 
(it  is,  of  course,  miich  covered  by  loose  deposits),  bordering  the  fibrolite- 
schists  on  either  side  and  separating  it  from  the  Monson  gneiss  below  It 
presents  no  peculiarities  of  interest. 


238  GEOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 

The  fibrolite-schists  are  deep-brown  biotite-schists,  in  wliicli  the  red- 
brown  shade  of  the  biotite  is  very  characteristic.  A  fine,  silky  fibrohte  is 
very  abundant.  Deep-red  garnets  are  common,  and  it  is  largely  due  to  their 
ready  decomposition  that  the  schists  have  always  at  surface  a  very  riisty 
appearance.  Nodular  masses  of  a  perfectly  fresh  and  limpid  moonstone, 
often  20-30"™  across,  and  generally  consisting  each  of  a  single  untwinned 
crystal,  appear  at  times  abundantly  in  the  schists,  whose  layers  wrap  round 
the  nodules  so  that  they  seem  like  pebbles.  They  are  often  surrounded  by  a 
border  of  sugary,  white,  granular  feldspar,  plainly  formed  by  the  crushing  of 
the  large  central  mass  and  the  slight  displacement  of  the  fragments  produced. 
This  displacement  becomes  at  times  considerable  in  the  direction  of  the 
bedding;  and  the  granular  material  is  drawn  out  in  tails  forming  complete 
"augen,"  which,  with  their  centers  of  orthoclase  as  limpid  as  calcite,  stand 
out  in  marked  contrast  with  the  deep  red-brown  of  the  schist.  They  inclose 
occasionally  garnet  and  graphite,  but  I  do  not  recall  an  inclusion  of  fibrolite. 
Grraphite  in  minute  scales  is  everywhere  present  in  the  rock  and  is  at  times 
quite  abundant. 

PETROGEAPHICAL   DESCRIPTION. 

Mica-schist  from  Ware.  In  the  bluff  near  the  contact  of  mica-schist  on 
hornblende-schist,  175  rods  southwest  of  B.  Bond's  house,  is  seen  a  black, 
fine-grained  schist  with  wavy,  shining  lamination  surface,  which  may  almost 
be  called  an  argillite,  with  rarely  deep-red  garnets  and  large  porphyi-itic 
spots  of  white  feldspar. 

In  section  the  dark  color  is  seen  to  be  due  partly  to  trains  of  coaly 
matter,  but  more  to  the  dark  color  of  the  biotite  scales,  which  are  dark 
olive-green  in  thin  plates. 

The  garnets  are  apolar  and  without  inclusions.  The  feldspar  is  ortho- 
clase, with  no  trace  of  microcline.  The  rock  is  very  interesting  from  the 
pseudofluidal  structure  developed  by  the  gradual  growth  of  the  orthoclase 
in  the  mass.  The  centers  are  large,  rounded  or  quadrangular  masses  of  feld- 
spar, showing  at  times  very  faint  undulose  extinction.  At  either  end  are 
grouped  a  congeries  of  intergrown  grains  vaiiously  arranged  optically,  and 
tapering  away  to  form  with  the  central  pieces  "augen,"  around  which 
trains  the  mica-scales  curve.  Outside  these  other  bands  of  feldspar  grains 
appear,  and  converge  in  either  direction  to  meet  and  inclose  the  central 
band  of  mica  scales.     Outside  this  another  band  of  mica  scales  widens  out 


THE  EASTERN  SYNCLINE.  239 

to  iiR'luilc  the  wlidle,  and  this  is  sometimes  repeated  several  times  on  one 
or  both  sides  of  the  center,  showing  a  gradual  growth  of  the  feldspar  within 
the  mass  of  the  mica-schist.  There  was  first  tlie  formation  of  the  large 
central  mass  and  its  welding  with  a  layer  of  the  mica  scales  at  its  surface 
(scattered  scales  of  the  same  mica  occur  within  the  large  feldspars),  and 
later  the  addition  of  other  granular  layers  of  feldspar  outside  the  first,  each 
retaining  in  contact  with  its  outer  surface  a  film  of  the  mica  scales.  Each 
feldspar  layer  has  possibly  some  relation  to  a  stage  in  the  folding  process 
of  the  rock,  by  which  strains  were  set  up  within  it  and  localized  at  the  sur- 
face of  the  feldspar  grains,  so  that  growth  of  new  feldspar  at  that  place  was 
made  possible. 

THE  HARDWICK  GNEISS. 

In  a  communication  to  the  Geological  Society  of  America  a\  New 
York  in  1889^  I  described  briefly  the  great  bands  of  granite  which  cross  the 
State  as  batholites  of  igneous  rock,  melted  up  along  great  synclines  of  the 
compressed  schists,  and  stated  that  the  Cambrian  biotite-gneisses,  which  are 
sometimes  finely  granitoid  from  recrystallization,  could  scarcely  be  distin- 
guished from  these  granites  made  schistose  by  crushing,  and  I  held  the 
Ban-e  and  Orange  bands  in  reserve,  as  their  relations  to  the  gneisses  and  to 
the  granites  were  so  evenly  balanced  that  I  could  not  decide  in  which  cate- 
gory to  place  them.  A  more  extended  study  of  the  band  across  Massachu- 
setts and  New  Hampshire  has  convinced  me  that  it  must  be  put  with  the 
intrusive  bands,  as  it  shares  so  m.any  of  the  characteristics  of  the  latter. 
It  is  intruded  as  a  broad  band  in  the  fibrolite-schists,  while  if  it  were  the 
Monson  gneiss  in  normal  relation  to  these  schists  in  the  core  of  an  anticline 
it  would  be  separated  from- them  on  either  side  by  amphibolite  and  whet- 
stone-schist, as  is  the  case  in  the  anticlines  next  east  and  west.  Now,  the 
northern  end  of  the  next  eastern  band — the  Orange  band — is  the  counter- 
part of  the  northern  end  of  this  mass.  The  shape  is  the  same;  the  rocks 
are  in  places  scarcely  distinguishable;  but  the  newer  rocks  seem  to  mantle 
round  the  Orange  area  as  around  a  core  of  gneiss,  and  the  band  can  be 
traced  continuously  south  into  union  with  the  Palmer-Monson  area,  where 
the  interbedded  quartzites  and  conglomerates  prove  the  mass  to  be  a  Cam- 

' Porphyritic  and  gneissoid  granites  in  Massachusetts:  Bull.  Geol.  Soc.  Am.,  Vol.  I,  1890,  p.  5.59. 
The  name  Barre  granite  used  here  has  been  changed  above  to  Hardwiok  granite  to  prevent  confusion 
with  the  Tvell-kuown  granite  of  Barre.  Vermont. 


240       GEOLOGY  OP  OLD  HAMPSHIRE  COUNTY,  MASS. 

brian  gneiss.  I  am  thus  constrained  to  leave  the  Orange  band  with  the 
gneisses  and  to  assign  the  Hardwick  band  to  the  granites,  in  spite  of  their 
resemblances.  The  latter  band  widens  as  it  goes  north,  and  crosses  the  State 
line  with  the  whole  width  of  the  country  between  Royalston  and  Winchen- 
don,  and  ends  with  the  characteristic  blunt  point  north  of  Fitzwilliam ;  and 
the  line  of  the  syncline  continued  passes  under  Monadnock,  and  the  granites 
possibly  continue  along  this  line,  beneath  the  mountain,  and  have  caused  the 
large  development  of  andalusite  in  its  schists,  as  they  have  on  the  border  of 
the  Princeton  band  and  in  the  center  of  the  Worcester  slates.  Only  its 
southern,  narrowed  end  enters  the  territory  under  review,  in  Ware,  and  runs 
down  the  eastern  portion  of  the  Palmer  quadrangle.  Across  the  whole  State 
the  narrower  western  portion  of  this  baud  is  a  very  dark  granitite — generally 
dark  from  excess  of  black  biotite,  more  rarely  by  the  presence  of  jet-black 
hornblende.  The  eastern  portion  is  an  excellent  biotite-muscovite-granite, 
like  that  of  Fitzwilliam.  The  darker  portion  is  well  exposed  in  the  railroad 
cut  at  Gilbertville,  and  is  described  below.  Where  the  Coys  Hill  granitite 
crosses  it  it  carries  large  "augen"  of  adularia,  like  the  adjoining  schists.  It 
is  thus  older  than  the  post-Carboniferous  granites. 

The  rock  may  be  studied  best  along  the  road  running  east  from  South 
Monson  and  near  the  east  line  of  the  town.  At  L.  Bradway's  it  resembles 
a  good  typical  Monson  gneiss,  as  also  at  B.  Brook's.  At  T.  Sutleff's  a  black 
granular  hornblende-granite,  a  dark  biotite-granite  with  amber  feldspar,  and 
a  granulite  full  of  shining- white  fibrolite  occur  on  this  terrane.  Such  fibro- 
lite  always  appears  to  have  been  dissolved  in  granite,  being  derived  from 
the  adjacent  fibrolite-schists. 

PETROGRAPHICAL    DESCRIPTION. 

At  the  first  cutting  on  the  Central  Railroad  northeast  of  Gilbertville 
station,  1 7  feet  east  of  a  pegmatite  dike,  occurs  a  rather  fine-grained  granite, 
nearly  black  from  the  abundance  of  biotite  and  magnetite,  and  of  slightly 
subporphyritic  aspect  from  the  presence  of  disseminated  scales  of  biotite, 
or  groups  of  scales  3-4°""  across. 

Under  the  microscope  it  is  a  wholly  fresh,  highly  crystalline  granitoid 
rock.  On  a  background  of  closely  interlaced  grains  of  oi'thoclase  and  plagio- 
clase  an  abundance  of  biotite,  magnetite,  and  epidote  appears.  Quartz  is 
wholly  or  almost  wholly  wanting,  and  there  is  no  trace  of  microcline.     The 


THE  EASTERN  SYNGLINE.  241 

olclur  constituents  are  apatite,  magnetite,  zircon,  rutile;  the  newer,  biotite, 
orthoclase,  albite,  epidote,  ])yrite.  Apatite  is  very  abundant,  as  is  also 
magnetite;  pyrite  is  rare.  The  abundant  biotite  shows  the  richest  absorp- 
tion colors. 

A  large  crystal  of  albite  contains  many  small,  sharp  plates  of  biotite 
parallel  to  0  P  (001)  and  oo  P  o6  (010),  and  the  section  is  so  exactly  parallel 
to  X  P  00  (100)  that  these  plates  are  both  presented  edgewise  to  the  eye. 
It  extinguishes  the  light  at  22°  and  23°  with  the  twinning  plane,  while  the 
mica  plates  make  witli  each  other  an  angle  of  94°.  It  is  also  crowded  with 
minute  black  rutile  (!)  microlites,  which  are  broken  up  to  an  unusual  extent 
into  short  rods,  or  often  into  long,  rigid  rows  of  black  dots  parallel  to  0  P 
(001)  and  oo  P  ob  (010),  and  in  other  directions  as  well.  The  epidote  usually 
associated  with  the  magnetite  shows  striking  absoi'ption — a  =  colorless,  h  = 
pale  mountain  green,  c  =  salmon  color.  The  zircon  is  in  small,  rounded, 
limpid  grains,  with  rounded  liquid  inclosures,  or  many  large  elongate,  stout 
prisms  with  several  constrictions  and  centrally  densely  dusted  with  black 
grains.  This  agrees  closely  with  the  type  of  zircon  occurring  in  the 
gneisses  as  determined  by  K.  de  Kroustchoff.^ 

PALMER. 

Across  this  town  the  western  band  of  amphibolite  is  broad  and  well 
marked;  it  commences  where  the  town  line  runs  north  nearly  to  the  Ware 
River,  and  continues  south  to  Fentonville,  being  well  exposed  west  of  E. 
Shorley's  in  the  middle  of  its  length.     The  eastern  band  is  wanting. 

The  mica-schist  extends  across  this  town  with  less  width  than  it  has 
thi'ough  Ware.  The  great  east-west  fault  through  the  south  of  Ware,  on 
the  south  of  which  the  rocks  are  thrust  far  to  the  westward  against  the 
granite,  seems  to  account  for  this.  The  schists  in  the  northern  half  of 
the  town  are  dark,  rusty,  fine-grained  biotite-schists,  in  which  fibrolite  is 
exceptionally  rare,  but  it  sets  in  again  abundantly  in  the  southern  part  of 
the  town. 

MONSON. 

The  same  series  crosses  Monson,  forming  the  crest  of  East  Hill  and 
Moulton  Hill,  and  crosses  the  State  line  east  of  Cedar  Swamp  Hill.     It  is 

'  Bull.  Soc.  Min.,  Vol.  XI,  p.  173. 
MON   XXIX 16 


242  GEOLOGY  OP  OLD  HAMPSHIEE  COUNTY,  MASS. 

well  exposed  in  a  section  continued  a  mile  east  from  the  town  farm,  or  east 
from  South  Monson,  past  the  house  of  T.  K.  Beckwith. 

After  passing  over  the  Monson  gneiss  and  the  amphibolite  one  comes 
upon  a  hand  of  gray,  fine-grained,  thin-fissile  gneiss  containing  garnets, 
which  represents  the  whetstone-schist,  but  is  so  thin  that  it  is  not  separately 
represented  upon  the  map.  It  contains  a  small  amount  of  fibrolite  in  the 
finest  needles. 

Just  above  it  is  a  dark,  fine-grained  mica-schist,  full  of  small  garnets 
and  spangled  with  transverse  biotite  that  exactly  resembles  the  Conway 
mica-schist,  except  that  it  contains  fibrolite. 

On  the  next  road  south,  in  the  roadside  by  S.  Blodgett's,  the  rock  is  a 
^'ery  striking  one.  It  was  originally  an  arenaceous  band  in  the  mica-schist, 
like  the  whetstone  layers  in  the  Conway  mica-schist  on  the  west  of  the  river. 
It  has  now  assumed  the  chocolate-brown  color  of  the  rest  of  the  rock,  and 
is  full  of  fibrolite  needles  that  wind  with  an  excellent  imitation  of  a  fluidal 
structure  around  porphyritic  masses  of  feldspar  or  garnet,  which  reach  a 
diameter  of  25-30™™,  and  very  closely  imitate  pebbles.  They  are  well 
rounded,  but  consist  in  each  case  of  a  single  crystal. 

The  feldspar  is  a  perfectly  fresh  and  slightly  opalescent  moonstone, 
regularly  penetrated  by  blades  of  plagioclase  so  exceedingly  fine  that, 
except  with  thin  plates  and  very  high  powers,  it  seems  to  be  an  orthoclase 
of  ideal  purity.  These  rounded  masses  are  bounded  by  a  sugary,  granular 
border  of  white  feldspar,  clearly  produced  by  the  crushing  of  the  central 
mass,  and  I  have  nowhere  seen  the  cataclase  structure  more  beautifully 
developed. 

The  average  rock  of  this  band  aci-oss  Monson  is  a  rusty,  chocolate- 
brown  biotite-schist,  everywhere  abundantly  fibrolitic  and  graphitic,  and 
very  generally  carrying  garnets.  Occasionally  it  is  changed  into  a  gneiss, 
as  described  above,  by  the  development  of  the  porphyritic  feldspars,  but 
this  seems  so  plainly  a  modification  of  the  mica-schist  during  folding,  by 
the  warping  open  of  cavities  which  became  filled  with  feldspar,  that  I  have 
not  separated  it  upon  the  map. 

On  the  east  of  the  mica-schist  only  traces  of  amphibolite  could  be 
found  along  the  line  of  separation  of  the  schist  and  the  band  of  gneiss 
still  farther  east,  and  this  could  not  be  given  on  the  map  without  great 
exaggeration. 


SILURIAN  SCHISTS  ON  EAST  SIDE  OF  VALLEY.  243 

THE  ZONE  OV  CONTACT  AROUND   TIIK   BEIiCIIERTOWN  TONAJ^ITE. 

THE    PYROXENIC    AMPHIBOLITES. 

An  inspection  of  the  map  will  show  that  the  crystalline  rocks  are 
thrown  off  on  all  sides  from  the  flanks  of  the  great  Belchertown  "batholite," 
and  that  great  sheets  of  the  same  rest  on  the  tonalite  far  out  in  the  center  of 
the  mass.  These  are  of  the  varieties  most  characteristic  of  intense  contact 
metaniorphism — coarse  fibrolite-  and  pyroxene-schists,  epidosites,  and  highly 
silicified  gneisses  and  quartzites. 

The  zone  of  crushing  following  the  foothills  through  Leverett,  Pelham, 
and  Belchertown  passes  directly  thi'ough  this  contact  border  and  materially 
increases  the  difficulty  of  identification  and  correlation  of  the  beds  with 
their  equivalents  elsewhere. 

It  is  not  possible  to  distinguish  between  the  beds  below  and  those 
above  the  amphibolite,  since  the  quartzite  becomes  heavily  loaded  with 
biotite,  forming  a  fissile  gneiss,  which  I  have  found  all  around  the  mass  and 
have  in  my  notes  called  the  Baggs  Hill  gneiss,  from  its  abundant  develop- 
ment in  this  hill  in  Granby  near  the  Belchertown  line.  As  soon  as  it 
approaches  the  granite  mass  the  amphibolite  becomes  pyroxenic,  as  at  Kel- 
leys  Crossing  and  on  south  down  the  west  side  of  the  mass,  while  the  Con- 
way schists  become  coarse  fibrolite-gneiss  and  epidosite. 

The  band  of  amphibolite  which  was  traced  through  Leverett  to  Adams's 
mills  reappears  between  the  two  Belchertown  ponds  and  wraps  around  the 
south  end  of  the  Pelham  gneiss,  uniting  the  Leverett-Amherst  area  and 
the  Pelham-Shutesbury  syncline,  and  extending  across  Belchertown  Center 
with  great  width  because  of  the  disturbing  influence  of  the  tonalite.  It  is 
much  shattered,  and  swarms  with  small  aplitic  dikes  from  the  tonalite. 

A  sahlite-amphibolite  appears  at  the  point  where  the  road  from  Amherst 
to  Belchertown  crosses  the  railroad — in  the  new  cutting  of  the  Massachu- 
setts Central  Railroad — and  a  short  distance  farther  south  in  the  cutting  of 
the  New  London  and  Northern  Railroad  at  the  next  crossing  (Kelleys 
Crossing). 

Here  the  rock  is  a  coarse  amphibolite  of  dark-green  color,  made  up 
almost  wholly  of  broad,  interlacing  plates  of  hornblende.  It  is  much  cut 
by  dikes  of  a  flesh-colored  granite  (aplite)  containing  little  mica,  which  send 
small  veins  through  it  in  all  directions,  recementing  the  brecciated  mass. 


244  GEOLOGY  OF  OLD  HAMPSHIEE  COUKTY,  MASS. 

Bordering  these  on  all  sides,  in  a  width  from  one-half  inch  to  2  inches,  the 
hornblende  is  changed  into  a  much  lighter  green  sahHte,  plainly  a  contact 
product.  At  the  south  outcrop  a  band  of  the  pyroxene  rock  much  wider 
occurs,  which  is  not  in  visible  relation  to  the  granite. 

The  schist  is  in  places  rendered  gneissoid  by  the  intrusion  of  sheets 
and  small  irregular  aggregations  of  flesh-colored  granular  feldspar,  which 
can  at  times  be  distinctly  traced  back  into  connection  with  the  granite. 

Followed  south  along  the  road  the  rock  becomes  again  a  chloritic  horn- 
blende-gneiss, and  just  beyond  and  east  of  its  southern  outcrop  appears  a 
band  of  quartzite  and  mica-schist,  which  is  exposed  in  the  cuts  of  the  two 
raih-oads  and  seems  to  overlie  the  hornblendic  rock,  as  indicated  in  the 
section  and  described  below.     (See  fig.  14.) 

In  the  roadside  165  feet  below  J.  Squire's  and  in  the  cuttings  of  both 
the  railroads  above  (east  of)  his  house  occurs  a  flat,  thin-fissile,  feldspathic 

Belchertown 

Village 


^~Quart.zit>e 


Fig.  14.— Section  of  schists  west  of  Belohertown.  A/nphiboAye. 


mica-schist  of  dark  greenish-gray  color  and  so  full  of  small  cubes  of  pyrite 
that  it  is  deeply  decomposed.  Dikes  of  coarse  pegmatite  from  1  to  25  feet 
wide  cut  through  it,  and  they  also  contain  pyrite  and  are  kaolinized  to 
great  depth.     The  mica-schist  is  10  feet  thick. 

Below  this  is  a  thin-bedded,  light-gray  quartzite,  slightly  biotitic  on 
cleavage  faces.  It  is  much  fissured,  and  filled  with  combs  of  quartz,  films 
of  hematite,  and  calcite,  and  slickensided.  Below  this,  on  the  west  side  of 
the  road,  is  a  massive,  crumbling  amphibolite,  which  seems  to  underlie  the 
quartzite.  The  section  is  here  sufficiently  undisturbed  to  show  the  amphib- 
olite in  normal  relation  to  the  upper  beds. 

Along  the  road  farther  south,  in  the  field  east  of  T.  S.  Haskel's,  is 
an  outcrop  of  a  coarse  sahlite-amphibolite,  like  that  at  Kelleys  Crossing, 
which  joins  Monson  gneiss  on  the  east  and  is  cut  off  by  a  great  granite 
vein  upon  the  south.  It  is  still  coarser  than  that  farther  north,  and  the 
pyroxene  crystals  are  larger.  It  furnished  the  material  for  the  microscopical 
description  of  the  rock  below.     It  is  a  massive,  friable,  granular  mass  of 


CONTACT  AROUND  BELCHERTOWN  TONALITE.  245 

greeu  p\TOxene  grains,  with  here  and  there  a  great  bhxck  hornblende  crystal 
appearing  porphyritically  in  the  mass,  its  shining  surfaces  luster-mottled 
bv  many  grains  of"  the  pale-green  pyroxene,  which  are  here  better  crystal- 
lized and  smaller  than  in  the  main  mass.  The  pyroxene  is  colorless,  without 
])ina<'oidal  cleavage  or  inclusions  of  any  kind. 

This  is  the  rock  that  was  called  augitic  syenite  by  President  Hitch- 
cock, and  slides  were  cut  from  the  specimen  in  the  survey  collection  (XVIII, 
92).  The  rock  contains  large  leek-green  crystals  of  pyroxene,  large  black 
hornblendes,  and  a  scanty  granular  groundmass  of  plagioclase. 

In  slides  the  dark-green  hornblende,  which  is  at  times  brown  centrally, 
is  luster-mottled  on  its  broad  cleavage  surfaces  with  pyroxene,  which  is 
faintly  reddish,  of  high  refraction  and  coarse  cleavage.  The  large  pyrox- 
enes are  intergrown  with  irregular  portions  of  hornblende  with  the  axes  a 
and  h  of  the  two  minerals  parallel.  In  sections  normal  to  h  the  cleavage 
lines  coincide  and  a  revolution  of  17°  to  19°  brings  the  hornblende  to 
extinction,  and  of  43°  in  the  same  direction,  the  pyroxene.  The  two  min- 
erals are  so  interwoven  that  they  give  almost  an  aggregate  polarization. 
Small,  brown  octahedra  appear  in  the  hornblende.  In  general  the  amphib- 
olite  is  not  made  pyroxenic,  but  is  only  crushed  and  filled  with  quartz  veins. 
It  is  the  usual  flat-fissile,  dark,  fine-fibrous  rock. 

Samples  from  an  artesian  well,  bored  on  the  grounds  of  Mr.  Myron  P. 

Walker,  in  the  center  of  Belchertown,  taken  at  the  depths  indicated,  gave 

the  following  results: 

Record  of  an  artesian-well  boring  in  Belchertoton. 

80  to  100  feet,  pegmatite. 

115  feet,  granite,  witli  little  amphibolite. 

130  feet,  granite,  with  little  amphibolite. 

145  feet,  granite. 

160  feet,  granite. 

175  feet,  yellow  granite,  with  much  muscovite. 

190  feet,  gray  granite,  with  amphibolite. 

205  feet,  gray  granite,  muscovite,  and  amphibolite. 

220  feet,  gray  granite,  muscovite,  and  amphibolite. 

249  feet,  much  coarse  biotite. 

Still  farther  south,  on  the  west  slope  of  Baggs  Hill,  in  Granby,  appear 
dark  greenish-gray,  membranous,  feldspathic  mica-schists,  associated  with  a 
quartzite  which  is  at  times  blackish,  at  times  greenish,  and  abounds  in  quartz 
crystals  and  pyrite. 


246  GEOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 

THE  FIBROLITE-SCHIST  INCLUSIONS. 

The  most  instructive  occurrence  to  prove  the  eruptive  character  of  the 
tonaHte  and  to  ilhxstrate  its  contact  phenomena  is  found  in  the  broad  sheet 
of  coarse  fibroUte-schist  which  runs  two  miles  southwest  from  "Slab  Citv," 
in  the  east  of  Belchertown,  to  end  at  the  house  of  V.  H.  Pease.  In  the  mid- 
dle of  the  road  that  runs  along  its  southern  border  at  the  western  Clough 
house — this  and  the  Pease  house  being  the  only  ones  on  this  road — at  a 
watering  trough,  a  brook  crosses  the  road,  coming  down  over  the  rocks,  and 
30  feet  above  the  road  one  sees  the  contact  of  the  tonalite  and  the  schists 
above  it,  and  at  the  trough  the  quartzite  appears  as  a  gramilar  quartz- 
eijidote  rock.  The  bright  yellow-green  epidote  is  in  rounded  crystals,  each 
surrounded  by  a  white  spot,  from  which  the  iron  has  gone  to  supply  the 
epidote  crystal. 

At  the  northeast  end  of  the  inclusion,  at  G.  Robinson's,  a  dark  biotite 
schistose  gneiss,  like  that  found  at  Baggs  Hill,  dips  normally  under  the 
fibrolite-schist.  The  biotite  is  black,  with  a  shade  of  green,  and  makes 
continuous  films  through  the  granular  quartz  mass.  Below  this  gneiss  are 
beds  of  a  thin-fissile,  slightly  micaceous  quartzite. 

This  fixes  the  position  of  the  fibrolite-schist  as  the  equivalent  of  the 
upper  mica-schist,  as  does  the  fact  that  it  lies  in  continuation  of  the  mica- 
schists  in  Enfield,  and  the  latter  are  the  only  beds  sufficiently  argillaceous 
to  have  furnished  material  for  so  much  aluminous  silicate.  These  same 
mica-schists  grade  eastward  into  fibrolite-schist  and  continue  across 
Worcester  County,  but  they  are  rarely  so  coarse  as  here, 

PETKOGRAPHICAL    DESCRIPTION. 

Fibrolite-cJilorite-scJiist,  from  bowlder  in  cutting  on  Massachusetts  Cen- 
tral Railroad,  South  Belchertown,  but  coming  doubtless  from  the  contact 
zone  of  the  granite;  a  stretched  gneiss-like  rock  of  gray  color,  with  shade 
of  green  and  showing  much  fibrolite. 

Under  the  microscope  radiated  fibrous  tufts  of  a  green,  chloritic  mineral 
inclose  much  graphite  in  notched  plates,  and  this  chlorite  is  associated  with 
an  abundance  of  large  garnet  grains  free  from  the  same  inclusions,  and 
these  together  frame  large  grains  of  quartz  full  of  rutile  needles.  The 
quartz  polarizes  as  a  mass  of  grains  and  is  plainly  secondary.  The  fibrolite 
is  abundantly  woven  through  the  whole. 


CONTACT  AROUND  BELCIIERTOWN  TONALITE.  247 

I'lbrofite-biotitc-schist,  from  south  end  of  the  main  belt  of  schist  in  the 
granite.  This  is  a  coarse  schist,  showing  an  abundance  of  muscovite  and 
biotite,  rusty,"  and  containing  large  spots  of  garnet  and  coarse  fibrolite 
blades,  often  3-5"""  wide. 

'J'he  microscope  shows  many  black  scales,  part  of  which  are  blood-red 
specular  iron,  and  part  seem  to  be  graphite,  as  they  are  grown  together  in 
long  lines  and  have  rounded  outlines.  There  are  many  rutile  needles  in 
the  quartz. 

Garnet-staurolite  rock,  from  large  bowlder  in  the  first  cutting  of  the 
Massachusetts  Central  Railroad  south  of  Belchertown,  and  coming  doubtless 
from  the  band  of  fibrolite  rock  to  the  north.  This  rock  represents  the 
extreme  of  metamorphism  reached  by  the  rocks  bordering  the  granite.  It 
is  a  highly  crystalline  rock  of  medium  grain.  Large  patches  of  garnet 
and  quartz  and  much  biotite  are  visible  to  the  eye,  and  the  lens  detects 
much  staurolite,  graphite,  and  a  few  shining  surfaces  of  fibrolite. 

Under  the  microscope  nearly  half  the  surface  is  occupied  by  stauro- 
lite; the  garnet  patches  are  seen  to  be  made  up  of  congeries  of  small 
grains,  and  these  two  separate  quite  widely  the  quartz  patches,  which  are 
crowded  with  fibrolite  and  rutile  microlites  and  are  thus  plainly  secondary 
quartz.  All  these  minerals  include  plates  of  graphite  scales — single  or 
grown  together  in  long  series. 

Epidote  rock,  from  Belchertown.  This  is  an  interesting  product  of 
the  contact  metamorphism  of  the  tonalite  upon  the  schist.  It  occurs  at  the 
watering  trough  near  the  house  of  J.  Clough,  in  the  southeast  part  of 
Belchertown.  The  rock  has  a  mottled  look;  a  white  groundmass  winds 
among  rounded  spots  of  a  dark  yellowish-green  color,  made  up  of  biotite 
and  epidote.     The  rock  grades  into  biotite-gneiss. 

The  epidote  is  the  most  abundant  constituent,  and  with  a  strong  lens 
one  can  make  out  the  fresh,  shining-,  model-like  crystals,  regularly  dis- 
seminated, and  semiopaque  centrally.  With  the  microscope  they  are  seen 
to  be  filled  with  grains  of  quartz,  of  elongate,  irregular  shapes,  and  very 
large  in  proportion  to  their  host,  which  crowd  the  central  portion  and 
radiate  outward.  It  contains,  also,  chlorite  scales.  Biotite,  regularly 
disseminated  and  strongly  dichroic,  molds  itself  to  the  epidote,  as  does  the 
rare  quartz.  Apatite  occurs  in  regular  crystals,  forming  pleochroic  rings 
in  the  biotite. 


248  GEOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 

All  the  constituents  are  perfectly  fresh  and  almost  entirely  free  from 
fluid  inclusions  and  microlites,  and  the  absence  of  these,  as  also  of  zircon, 
rutile,  garnets,  and  iron  ore,  is  remarkable. 

Hand  specimens  are  on  one  side  biotite-gneiss,  on  the  other  epidosite, 
and  the  two  seem  normally  interlaminated ;  but  the  latter  must  be  of  later 
and  very  different  origin,  and  may  be  in  effect  a  vein  stone,  in  which,  per- 
haps, the  chlorite  scales  are  remnants  of  the  earlier  rock,  which  has  been 
almost  wholly  resorbed  to  make  place  for  the  new  minerals. 

THE  WILBRAHAM  SYlSTCIilNE. 

South  of  the  deep  transverse  valley  of  the  Quabaug  and  its  continua- 
tion in  the  Chicopee  River,  the  simplicity  of  the  geology  is  as  marked  as  is 
the  complexity  of  the  region  north  of  the  same  valley.  Three  great  syn- 
clines  of  the  schists  run  south  across  the  towns  named  above,  forming  as 
many  high  ridges.  The  Wilbraham  sjmcline  looks  down  on  the  sands  of 
the  Connecticut  Valley  on  the  west  and  upon  the  deep  gneiss-bottomed 
valley  of  East  Wilbraham  on  the  east,  and  across  this  valley  rises  the  West 
Mountain  of  Monson,  made  up  of  a  second  syncline  of  the  same  rocks  and 
looking  down  on  the  deeper  and  narrower  Monson  Valley,  which  is  under- 
lain by  the  same  gneiss.  Across  this  valley  on  the  east  the  third  syncline 
rises  to  form  East  Mountain,  which  is  bordered  on  the  east  by  a  less  strongly 
marked  and  yet  distinct  valley,  underlain  by  a  third  repetition  of  the 
Monson  gneiss  and,  followed  farther  east,  by  the  Brimfield  gneissoid  mica- 
schists,  forming  a  foiirth  syncline.  (See  sections,  PI.  XXXII,  and  map, 
PI.  XXXIV.) 

The  Wilbraham  syncline  is  concealed  in  its  western  half  beneath  the 
Triassic  sandstones,  which  rest  against  the  western  foot  of  the  ridge,  and 
the  slope  of  the  ridge  on  the  west  is  so  steep  that  it  is  probable  that  the 
fault,  so  well  marked  farther  north,  is  continued  at  its  base,  and  that  the 
rocks  have  sunk  to  form  the  broad  Connecticut  Valley.  It  is  a  closed 
fold,  slightly  overturned  to  the  west,  and  its  rocks  closely  resemble  the 
corresponding  beds  on  the  west  of  the  Connecticut  Valley  in  Granville. 

The  gneissoid  quartzite  or  muscovitic  gneiss,  the  equivalent  of  the  Rowe 
schist,  which  usually  intervenes  between  the  Monson  gneiss  and  the  horn- 
blendic  beds,  seems  to  be  wanting  here,  and  the  hornblendic  beds  rest 
directly  on  the  white  biotite-gneiss.  The  upper  beds  of  this  gneiss  are  very 
fine-grained  and  magnetitic  and  probably  represent  the  Rowe  schist,  but 


THE  WILBRAHAM  AND  MONSON  SYNGLINES.  249 

no  bolln(lal■^•  could  be  drawn  below  to  separate  it  from  the  Monson  gneiss 
proper. 

The  hornblende-schist  (Chester  amphibolite)  is  a  jet-black  rock,  satiny 
on  the  surface  from  the  eifect  of  the  great  number  of  fine  needles  of  horn- 
blende which  make  up  nearly  its  whole  mass.  The  whetstone-schist  (the 
equivalent  of  the  Sa\'oy  schist)  is  a  gray,  granular,  friable  quartzite,  vary- 
ing from  thin-fissile  to  massive,  often  a  shining  muscovite-quartzite,  or 
abounding  in  distant  flakes  of  chlorite.  It  is  covered  on  the  western  flank 
of  the  syncline  until  the  range  crosses  into  Connecticut,  when  it  appears  on 
the  west  flank  of  Perkins  Mountain. 

The  Conway  mica-schist  is  a  coarse,  light-gray  muscovite-schist,  gen- 
erally barren,  but  caiTying  at  times  a  few  garnets.  Along  its  western  base 
it  is  much  crumpled  and  silicified,  as  if  from  the  influence  of  the  fault. 

On  passing  into  Connecticut  the  regularity  of  the  syncline  is  interrupted. 
The  amphibolite  band  which  forms  the  ridge  of  Pine  Mountain,  Rattlesnake 
Hill,  and  Perkins  Mountain,  in  Somers,  is  suddenly  cut  off"  in  the  south 
shoulder  of  Perkins  Mountain  by  the  gneiss.  The  latter  rock,  which  up  to 
this  point  has  dipped  a  little  north  of  west,  here  swings  around  sharply,  dip- 
ping steeply  north  and  northeast,  so  as  to  cut  off  the  whole  series  up  to  the 
mica-schist,  and,  reversing  its  direction,  it  runs  south  again,  dipping  normally 
beneath  the  Conway  schist,  of  course  with  a  fault  boiuidary. 

THE  MOKSON   SYlSrCLIKE. 

The  west  Monson  syncline  is  a  perfectly  symmetrical  closed  fold  of  the 
scliistose  series  in  the  gneiss,  and  its  character  will  be  understood  by  com- 
paring the  detailed  section  below  with  the  cross-sections  on  PI.  XXXII.  The 
section  given  below  commences  with  the  older  rock — the  Monson  gneiss — 
on  the  east,  at  a  point  1,830  feet  east  of  the  sharp  turn  in  the  road  at  the 
house  of  A.  Bliss,  jr.,  a  mile  northwest  of  Peaked  Mountain,  and  runs  west : 

a.^  Monson  gneiss. 

b.  Eowe  schist.  Gneissoid  quartzite,  with  very  little  feldspar,  muscovite,  and  a 
green  mica  or  chlorite,  with  beds  of  gray  biotite-quartzite,  chlorite-schist,  and  horn- 
blende-schist appearing  a  little  farther  north,  opposite  the  house  of  J.  Burley ;  361  feet. 

d.  Chester  amphibolite.  Epidotic  quartz-hornblende-schist,  thin-bedded  above 
and  changing  into  chlorite-schist;  459  feet. 

e.  Savoy  schist.  Cbloritic  mica-schist,  with  subordinate  beds  of  muscovite- 
gneiss,  changing  above  into  arenaceous  mica-schist  (whetstone-schist)  and  still  higher 

'  These  italic  letters  refer  to  sections  described  on  pages  213-214. 


250  GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

iuto  quartzite  and  quartzose  sericite-schist,  with  pale-greeu  hydrated  muscovite  and 
large  distant  garnets;  3,791  feet. 

/.  Conway  schist.  A  coarse,  lead-gray,  barren  mica-schist  occupies  about  half 
the  thickness  of  this  bed  and  is  succeeded  above  by  a  corrugated  mica-schist  of  fine 
grain,  very  dark,  from  the  large  amount  of  graphite  in  it,  and  abounding  in  small 
garnets  (oo  P)  and  dark  red-brown  biotite,  set  transversely  to  the  bedding;  1,188  feet. 

The  similarity  of  this  series  to  the  corresponding  one  across  the  Con- 
necticut Valley  is  striking.  Each  subdivision  between  the  Becket  gneiss 
and  the  Leyden  argillite  is  represented,  though  vpith  diminished  thickness. 
The  Savoy  schist  (e)  is  well  exposed  in  the  first  cutting  west  of  the  Palmer 
station  on  the  Boston  and  Albany  Railroad.  Here  there  is  trace,  apparently, 
of  a  corrugation  of  the  quartzite,  upon  which  the  vertical  foliation  may  be 
superinduced  as  a  secondary  structure.  This  would  throw  doubt  upon  the 
thickness  given  above.  Following  the  Somers  turnpike  a  mile  and  a  half 
west  from  the  south  end  of  State-line  Pond,  in  Connecticut,  at  the  south  end 
of  the  long  ridge  of  Peaked  Mountain  one  comes  upon  the  finest  quartz- 
conglomerate  in  the  Rowe  schist.  It  is  in  a  great  ridge  on  the  north  side 
of  the  road,  at  a  ruined  house  northwest  of  the  schoolhouse. 

The  mica-schist  (/),  the  central  portion  of  which  agrees  strikingly  with 
the  Conway  schists  clear  across  the  town,  is  best  studied  where  the  road 
from  iPalmer  to  Hampden  crosses  it,  a  mile  northwest  of  Flynt's  quarry. 
The  uppermost  beds  are  so  fine-grained  and  plumbaginous  that  they  recall 
the  Leyden  argillite,  and  this  is  exactly  the  horizon  at  which  it  should 
occur. 

If  the  section  be  continued  westward  it  repeats  itself  exactly  in  inverse 
order,  though  here  the  amphibolite  is  very  generally  porphyritic  in  appear- 
ance— a  structure  which  is  due  usually  to  the  absence  of  hornblende  from 
small  spots  regularly  disseminated,  so  that  the  whole  granular  groundmass 
shows;  but  many  bowlders  of  the  rock  found  in  the  southwest  corner  of 
Monson  are  of  fine,  porphyritic  diorite-schist  with  fresh,  poorly  cleaving 
feldspars  in  close-set,  rounded  grains. 

It  seems  to  me  probable  that  a  narrow  fragment  of  rocks  of  this  series 
starts  east  of  Flynt's  quarry,  near  the  "rock  house,"  and  extends  north 
thrditgh  Bunyan  Mountain,  either  faulted  down  into  the  center  of  the  anti- 
cline or  brought  there  by  a  subordinate  downward  fold  of  the  schist  which 
foi-merly  mantled  over  the  gneiss.  It  was  of  too  limited  extent  to  find  place 
upon  the  map. 


CONTACT  AROUND  BELCHERTOWN  TONALITE.  251 

THE  BAST  GREElSrwiCII-ENFIELD  SYNCLINE. 

A  naiToM'  s>-iu'liue  comes  out  from  beneath  the  sands  east  of  Green- 
wich village  and  near  the  east  line  of  Greenwich.  Traces  of  it  appear  to 
the  north,  mostly  covered  by  sand,  along-  the  roadside  east  of  Warner's  pond. 
It  makes  tlie  high  hill  which  extends  down  the  east  line  of  Greeiiwich  and 
Enfield,  and  is  well  exposed  along-  the  road  running  east  from  Enfield. 
Here,  near  W.  N.  Avery's,  the  fibrolite-schist  is  a  nearly  pure  bucholzite, 
in  thick  layers,  in  a  fine-grained  feldspathic  quartzite  without  brown  mica, 
gi'aphite,  or  garnet.  As  it  lies  immediately  above  the  amphibolite  it  occu- 
pies the  position  of  the  whetstone-schist.  The  center  of  the  series  is  occupied 
by  the  rusty  mica-schist,  while  on  the  west  there  is  a  dull-greenish  graphite- 
garnet-muscovite-schist  and  a  granulite  with  its  gai-nets  bordered  by  green, 
and  both  these  beds  indicate  the  presence  of  the  basal  beds  below  the 
amphibolite,  but  not  in  thickness  sufficient  to  be  put  upon  the  map.  In 
Ware  this  terrane  is  well  exposed  between  the  town  farm  and  the  schoolhouse 
to  the  west. 

It  is  shifted  to  the  west  by  the  great  fault  in  the  south  of  Ware,  and 
across  Palmer  it  forms  the  high  Pattaquattic  Hill  and  the  range  of  high 
ground  south  across  the  town.  On  the  south  flank  of  this  hill,  northwest 
of  J.  Can-igan's,  the  black  mica-schists  are  locally  so  crowded  with  the 
large  rounded  "augen"  of  feldspar  that  the  separated  folia  of  the  schist, 
2-5""  thick,  w^ind  in  and  out  among  the  latter  and  occupy  not  more  than  a 
fourth  of  the  space  in  a  cross-section  of  the  rock. 

In  Palmer  it  can  best  be  studied  along  the  road  running  east  from  the 
Center,  and  its  first  branch  to  the  northward,  especially  in  the  hill  east 
of  B.  Olney's.  Here  a  distinct  band  of  quartzite  appears  above  the  amphib- 
olite.    It  runs  out  soon  after  reaching  Monson. 

EESUME. 

ARGUMENT    FOR    THE    IDENTITY    OF   THE    SCHIST    SERIES    EAST    OF    THE 
CONNECTICUT    WITH    THOSE    ON    THE    WEST. 

In  the  north  of  the  State  the  beds  in  the  first  band  east  of  the  river 
agree  most  closely  with  the  con-esponding  beds  west  of  the  river,  and  some 
of  them,  as  the  Conway  schists,  agree  exactly  in  a  multitude  of  characters. 
Southward  the  strata  change  greatly,  but  in  the  latitude  of  Amherst  the 


252  GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

corresponding  strata  east  and  west  of  the  river  still  resemble  eacli  other 
closely.  Farther  south  the  beds  revert  to  the  types  prevalent  in  the  north- 
ern part  of  the  State,  but  with  many  minor  peculiarities,  and  still  the  resem- 
blance is  close,  bed  for  bed,  between  those  on  the  east  and  those  on  the 
west  of  the  river. 

THE  PASSAGE  EASTWARD  INTO  THE  BRIMFIELD  FIBROLITE-SCHIST. 

On  the  north  of  Warwick  the  Conway  schists  agree  exactly  with  those 
in  the  Northfield  syncline  next  west,  and  thus  with  the  type  west  of  the 
river.  As  the  beds  are  traced  south  along  the  strike  they  gradually  become 
fibrolitic,  and  the  same  change  takes  place  slowly  across  the  strike  as  one 
goes  eastward  into  higher  beds. 

Because  of  the  abundance  of  granite,  metamoi-phism  is  more  pro- 
nounced in  the  central  part  of  the  State,  and  here  fibrolite  occurs  in  the 
schists  all  the  way  to  the  Connecticut.  Again,  where  the  nonfibrolitic 
Conway  schist  passes  out  over  the  Belchertown  tonalite  it  becomes  most 
coarsely  fibrolitic.  Finally,  as  the  beds  are  followed  still  farther  east 
across  Worcester  County  the  great  increase  of  granite  promotes  a  corre- 
sponding increase  of  fibrolite  in  the  highly  aluminous  Conway  schists,  and 
they  are  named  for  convenience  the  Brimfield  schists. 


CHAPTEE    IX. 
THE  BERNARDSTON  SERIES  OF  UPPER  DEVONIAN  ROCKS. 

LITERATURE. 

1.  1819.    B.Hitchcock.    Geology  of  a  section  of  Massacliusetts  on  Coiiuecticut  Eiver, 

etc.    Am.  Jour.  Sci.,  1st  series,  Vol.  I,  p.  105. 

2.  1823.    E.  Hitchcock.     Geology,  etc.,  of  the  regions  contiguous  to  the  Connecticut 

River,  with  map.    Ibid.,  Vol.  VI,  p.  1. 

3.  1825.    E.  Hitchcock.    Same  article,  separate  publication. 

4.  1832.    E.  Hitchcock.    Eeport  on  the  Geology  of  Massachusetts.     Part  I,  Economic 

Geology,  with  map.    Ibid.,  Vol.  XXII,  p,  1. 

5.  1833.    E.  Hitchcock.    Eeport  on  the  Geology,  etc.,  of  Massachusetts,with  atlas. 

6.  1835.    E.  Hitchcock.    Eeport  on  the  Geology  of  Massachusetts.    2d  edition,  702 

pp.;  map. 

7.  1841.    E.  Hitchcock.    Final  Eeport  on  the  Geology  of  Massachusetts.    831  pp.; 

map. 

8.  1844.    E.  Hitchcock.    Explanation  of  the  newly  colored  map  of  Massachusetts. 

22  pp. 

9.  1844.    E.  Hitchcock.    Geological  map  of  Massachusetts,  on  same  sheet  as  the 

Borden  Trigonometrical  Survey  Map. 

10.  1851.    E.  Hitchcock.    On  the  geological  age  of  the  clay  slate  of  the  Connecticut 

Eiver  Valley.    Proc.  Am.  Assoc.  Adv.  Soc,  Vol.  VI,  p.  298. 

11.  1858.    E.  Hitchcock.    Geological  map  of  Franklin  County,  on  Walliug's  wall  map 

of  Franklin  County. 

12.  1861.    E.  Hitchcock  and  C.  H.  Hitchcock.    Eeport  on  Geology  of  Vermont.    Vol. 

I,  p.  447;  Vol.  II,  p.  598. 

13.  1870.    C.  H.  Hitchcock.    The  Geology  of  Vermont,  in  the  Geology  of  Northern 

New  England. 

14.  1871.    C.  H.  Hitchcock.    Geological  map  of  Massachusetts,  in  Walliug's  Atlas  of 

the  State.    Boston. 

15.  1873.    J.  D.  Dana.    On  rocks  of  the  Helderberg  era  in  the  valley  of  the  Con- 

necticut; the  kinds  including  staurolite  slate,  hornblende  rocks,  gneiss, 
mica-schists,  etc.,  besides  fossiliferous  limestone.  Am.  Jour.  Sci.,  3d  series. 
Vol.  VI,  p.  339. 

253 


254       GEOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS, 

16.  1877.    C.  H.  Hitchcock.    Note  upon  the  Connecticut  Valley  Helderberg.    Ibid., 

Vol.  XIII,  p.  313. 

17.  1877.    C.  H.  Hitchcock.    The  Geology  of  New  Hampshire.    Vol.  II,  p.  428,  with 

map  and  sections. 

18.  1877.    J.  D.  Dana.    Note  on  the  Helderberg  formation  of  Bernardston,  Massa- 

chusetts, and  Vernon,  Vermont.    Am.  Jour.  Sci.,  3d  series,  Vol.  XIV,  p.  379. 

19.  1883.    R.  P.  Whitfield.    Observations  on  the  fossils  of  the  metamorphic  rocks  of 

Bernardston,  Massachusetts.    Ibid.,  Vol,  XXV,  p,  368. 

20.  1890.    Ben  K.  Emerson,    A  description  of  the  Bernardston  series  of  metamorphic 

Upper  Devonian  rocks.    Ibid.,  Vol.  XL,  pp.  263,  362. 

HISTORY. 

1819.  "Argillite  sometimes  alternating  with  mica-slate,  siliceous  slate," 
"undoubtedly  primitive."  Almost  perpendicular,  inclining  a  few  degrees 
to  tlie  west.  (1,^  p.  105.)  The  hornblende-schist  of  this  series  is  associated 
with  the  Triassic  "greenstone."     (1,  p.  109.)  ■ 

1823.  Extends  from  Leyden,  north  to  Rockingham,  Vermont;  occurs 
again  at  Woodbridge,  Connecticut;  often  tortuous  and  slightly  undulating, 
especially  when  passing  by  imperceptible  changes  into  mica-slate.  It 
embraces  numerous  beds  and  "tuberculous  masses"  of  white  quartz. 
It  also  alternates  with  mica-slate,  and  a  peculiar  coarse  limestone  forms 
beds  in  the  argillite.  The  map  separates  the  argillite  from  the  mica-slate 
on  the  west  by  a  continuous  band  of  limestone  and  extends  it  eastwardly  to 
include  all  the  mica-schists  which  have  been  associated  with  the  Bernards- 
ton  limestone  in  later  time,  while  the  mica-schists  on  the  eastern  side  of 
the  river  are  associated  with  the  mica-slate  west  of  the  argillite,     (2,  p.  36.) 

The  hornblende  rock  is  separated  as  primitive  greenstone  in  the  north 
of  Gill  and  south  of  West  Northfield.     (2,  p.  31.) 

1832.  The  limestone  and  magnetite  beds  which  had  been  worked  forty 
or  fifty  years  before,  but  had  produced  poor  iron,  are  described  briefly  in 
their  economic  aspect  but  without  geological  data.  (4,  p.  27.)  It  was 
supposed  to  form  a  bed  in  the  argillite.  Compares  it  in  value  with  a  gold 
or  silver  mine. 

1833.  Fossils  discovered  in  the  limestone  and  figured  (6,  atlas,  pi.  14, 
p.  47) ;  and  the  limestone,  though  not  seen  in  contact,  supposed  to  lie  uncon- 
formably  upon  the  argillite.     The  quartz  rock  lying  above  the  limestone, 

'  The  numbers  1,  2,  3,  etc.,  refer  to  the  numbers  above  under  the  head  of  Literature. 


BEKNAKDSTON  SERIES  OF  UPPER  DEVONIAN.  255 

but  not  seen  in  contact,  is  noted.  The  complex  folding-s  of  tlie  arf)-illite 
iu-e  described  and  fig'ured.  (6,  pp.  289,  295.)  Concludes  that  the  encrinal 
limestone  is  newer  than  the  argillaceous  slate. 

1841.  Doubts  are  expressed  as  to  the  encrinal  character  of  the  fossils. 
The  relations  of  the  argillite,  limestone,  and  quartzite  described  as  before. 
(7,  pp.  54,  556,  560.) 

1851.  Because  of  the  discovery  of  an  upper  stratum  of  slate  (the  upper 
schist  described  below)  beneath  which  the  limestone  passes,  it  is  decided 
that  the  whole  of  the  argillite  together  with  all  the  series  to  the  top  of 
the  upper  schist  of  the  section  on  page  258  is  Devonian,  in  accordance 
with  the  determination  of  the  crinoids  by  Prof  James  Hall,  who  thought 
them  to  be  of  the  age  of  the  Onondaga  limestone.     (10,  p.  298.) 

1858.  Bernardston  and  West  Northfiekl  are  divided  about  equally  by 
a  north-south  line  between  argillaceous  slate  on  the  west  and  hornblende- 
schist  on  the  east,  with  the  number  for  mica-slate  entered  on  the  area 
of  the  latter,  but  not  subdivided  from  the  rest.  Limestone  and  iron  ore 
marked.     (11-) 

1861.  While  the  preceding  history  has  dealt  entirely  with,  the  work  of 
President  E.  Hitchcock,  I  understand,  though  it  is  not  distinctly  stated  in  the 
chapter  in  question,  that  the  report  of  the  Vermont  survey  was  based  upon 
the  studies  of  Prof  C.  H.  Hitchcock,  and  I  have  so  indicated  above 

Under  the  heading  "Upper  Helderberg  Limestone"  is  given  the  best 
section  yet  published  of  the  rocks  in  question,  containing  every  bed  of 
importance  except  one,  and  indeed  one  bed,  D,  a  clay-slate  immediately 
above  the  limestone,  which  does  not  exist.  All  the  beds  from  the  argillite 
up  are  made  conformable,  but  no  other  indication  is  given  in  the  chapter  as 
to  how  much  of  the  series  is  assigned  to  the  age  indicated  in  the  heading. 
The  upper  quartzite  (that  is,  the  quartzite  east  of  the  limestone  on  the 
Williams  farm)  is  suspected  to  rest  unconformably  upon  the  argillite  in  Ver- 
non, the  intervening  members  being  absent,  and  on  page  598  of  Vol.  II  this 
quartz  rock,  with  the  gneiss  into  which  it  grades,  is  assigned  to  the  Devo- 
nian age,  from  its  identity  with  the  iipper  quartzite  of  the  Williams  farm  sec- 
tion. Attention  is  called  to  the  fact  that  an  upper  schist  resting  upon  the 
quartzite — it  is  described  as  a  "distinct  clay-slate,  thicker-bedded  and  harder 
than  most  clay-slates" — is  not  elsewhere  seen  resting  upon  the  quartzite. 
This  I  have  not  found  to  be  true.     (12,  Vol.  I,  p.  447;  Vol.  II,  p.  598.) 


256  GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

1870.  Prof.  C.  H.  Hitchcock  classes  the  argilHte  as  Upper  Silurian,  and 
the  Bernardston  series  is  "doubtfully  referred  to  the  Devonian."  "Both 
above  and  below  ai-e  quartzites  not  of  gi'eat  thickness,  and  also  slates." 
(13,  p.  4.) 

1873.  Prof  J.  D.  Dana  pronounced  the  argillite  to  be  an  older  formation 
lying  unconformably  below  the  other  members  of  the  series,  as  supposed  by 
E.  Hitchcock  in  1833  for  the  argillite  in  relation  to  the  limestone — an 
opinion  receded  from  on  the  discovery  of  an  upper  band  of  slate — and  by 
C.  H.  Hitchcock  in  1861  for  the  overlying  quartzite.  From  the  close 
resemblance  of  the  mica-schist  and  quartzite  on  the  other  side  of  the  Fall 
River  Valley  to  that  on  the  Williams  farm,  he  assigns  to  the  age  of  the 
Helderberg  these  and  the  new  rocks  associated  with  them,  viz,  staurolite, 
mica-schist,  hornblende  rock,  and  feldspathic  quartzite,  which  comes  at  last 
closely  to  resemble  trae  gneiss. 

He  concluded  that  the  Coos  group  of  Professor  Hitchcock,  if  correctly 
traced  out,  was  the  continuation  northward  across  New  Hampshire  of  the 
Helderberg  rocks,  and  that  the  two  bands  of  hornblende  rocks  marked 
upon  Prof  E.  Hitchcock's  geological  map  of  Massachusetts  as  extending 
across  the  latter  State,  with  their  continuation  southward  in  Connecticut, 
as  described  by  Percival,  where  they  pass  beneath  the  New  Red  sandstone 
near  Middletown,  and  emerge  again  west  of  New  Haven,  were  possibly  to 
be  assigned  to  the  same  horizon. 

1877.  In  1877  Professor  Hitchcock,  first  in  abstract  in  the  American 
Journal  (16),  and  later  in  the  Geology  of  New  Hampshire  (17),  gave  the 
result  of  a  new  investigation  of  the  region  in  question,  which  diverges  in 
a  remarkable  degree  from  his  own  and  his  father's  conclusions  and  from 
those  of  Professor  Dana.  Accepting  the  conclusion  of  the  latter  that  the 
argillite  is  an  older  and  unconformable  bed  beneath  the  strata  in  question, 
he  claims  that  the  limestone  "does  not  certainly  dip  beneath  the  quartzite," 
but  "maybe  a  remnant  of  a  once  extensive  deposit  covering  both  the 
other  formations  mentioned,  and  what  remains  is  in  an  inverted  position," 
and  thus  is  newer  than  all  the  other  rocks  of  the  region.  This  decided 
change  of  opinion  caused  a  discrepancy  in  the  volume  already  cited,  as,  in 
the  earlier  part,  the  series  is  stated  to  consist  of  several  thousand  feet  of 
quartzite,  limestones,  schists,  etc.,  and  probably  hornblende-schists.  (17, 
p.  18.) 


BEBNAKDSTON  SEKIES  OF  UPPER  DEVONIAN.  257 

lu  his  uiiitured  conclusions  (17,  p.  428  ff)  the  gneissoid  rocks  which 
in  tht'  Vermont  report  are  stated  to  appear  to  pass  imperceptibly  into  the 
(piartzites,  and  to  rest  invariably  upon  them,  and  therefore  to  be  newer 
(12,  Vol.  II,  p.  598),  are  classified  as  Bethlehem  gneiss,  and  thus  assigned 
to  the  Laurentian.  The  band  of  this  gneissoid  rock  crossing  the  State 
line  west  of  South  Vernon  is  marked  on  the  map  (17,  PL  XVIII)  as 
Bethlehem,  but  in  the  atlas  to  the  same  volume,  prepared  later,  it  is  colored 
as  Coos  qiiartzite,  but  left  in  the  section  at  the  foot  of  the  sheet  as  gneiss. 

The  liornblende-schist  is  next  described,  and  its  extension  southward 
through  Gill  pointed  out,  and  it  is  referred  to  the  same  horizon  as  the 
Shelburne  Falls,  Massachusetts,  baud,  and  both  are  assigned  on  the  scale 
of  colors  of  the  map  to  a  position  below  the  Huronian.  The  argillite  is 
described  as  Cambrian  clay-slate — that  is,  as  Primordial  Silurian. 

The  remainder  of  the  series  on  both  sides  of  Fall  River  and  east  of 
the  Connecticut  thi'ough  Northfield — quartzite,  mica-schist,  and  staurolite- 
slate — is  assigned  to  the  Coos  group,  and  this  is  placed,  in  the  stratigraph- 
ical  column  at  the  end  of  the  book,  beneath  the  calciferous  mica- schist, 
and  to  the  whole  is  given  a  position  in  the  Paleozoic  series  above  the 
Cambrian  and  below  the  Lower  Helderberg. 

Professor  Hitchcock  calls  attention  to  one  very  important  matter — the 
absence  of  staurolite,  hornblende  rocks,  and  feldspathic  quartzite  from  the 
Williams  fann  section,  and  their  presence,  with  the  absence  of  limestone, 
on  the  other  side  of  the  narrow  Fall  River  Valley.  In  his  final  column  of 
the  rocks  of  the  State  (17,  p.  674)  a  thickness  of  500  feet  is  assigned  to 
the  Helderberg,  which  is  not  clear  if  only  the  limestone  is  to  be  assigned 
to  that  age. 

During  the  same  summer  I  visited  this  region  with  Professor  Dana  and 
we  went  over  the  ground  between  Bernardston  and  South  Vernon  together, 
examining  the  Williams  farm  section  carefully.  I  then  called  his  attention 
to  the  lower  stratum  of  schist  beneath  the  limestone,  and  soon  after  detected 
fossils  in  the  quartzite  over  the  latter.  These  we  found  to  be  quite  abund- 
ant. On  his  return  Professor  Dana  gave  the  results  of  this  examination 
and  controverted  the  conclusions  of  Professor  Hitchcock  in  a  somewhat 
polemical  paper  (18),  giving  in  some  detail  the  earlier  opinions  of  the 
latter,  and  deciding  that,  since  the  quartzite  was  both  fossiliferous  and 
conformable  upon  the  limestone,  the  two  could  not  be  brought  into  their 

MON  XXIX 17 


258 


GEOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 


present  position  by  faulting  or  inversion,  and  since  the  schist  occurs  both 
below  and  above  the  limestone  in  apparent  conformity,  one  or  other  of 
the  beds  must  be  newer  than  the  latter. 

Both  of  the  members  of  the  Coos  gi-oup  being  thus  proved  to  be  of 
the  same  age  as  the  limestone — the  quartzite  by  containing  fossils  and  the 
schist  by  conformity  with  the  latter  and  with  the  limestone — numerous 
examples  of  visible  and  conformable  conjunction  of  the  hornblende-schist 
and  gneiss  with  both  the  mica-schist  and  the  quartzite  in  the  area  between 
Bernardston  and  South  Vernon  are  given,  together  with  instances  of  the 
passage  of  the  one  rock  into  the  other,  in  proof  that  these  rocks  are  there 
all  of  Helderberg  age. 

Order  of  succession  of  rocks  in  the  Bernardston  region. 


Hitchcock. 

Dana. 

Emerson. 

•i 

% 

■3 
P-i 

Lower    Helderberg 
limestone. 

1. 

u 

IS 

a 

Fossiliferous  limestone. 

Mica-schist. 

Staurolite-schist. 

Hornblende-schist. 

Quartzite. 

Feldspathic  quartzite. 

Gneiss. 

[The    order   of   the 
above  beds  was  not 
fixed.     The  list  in- 
cludes  all  of  the 
preceding  list  ex- 
cept calciferous 
mica-schist  and  ar- 
gillite]. 

i 
1 

a 
S 

1 

1.  Garnetiferous  mica- 

schist,   becoming 
staurolltic    east 
and  north,  with 
four  or  more  beds 
of  amphibolite. 

2.  Quartzite,    con- 

glomeratic   at 
base;     becoming 
gneissoid  east  and 
north,  with  mag- 
netite and  crinoi- 
dal    limestone 
beds     carrying 
Chemung  fossils. 

Calciferous  mica-schist. 

Staurolite  mica-schist. 

Ph 

2 

CD 

o 

O 

Mica-schist,  often 
stauroliferous. 

Quartzite. 

Cambrian    slates  ^ar- 
gillite. 

i 
1 

i 

§ 

1 

Bethlehem  gneiss. 

Unconformity. 
Argillite. 

a 

TJnconformity(  ?). 
3.  Argillite. 

4.  Calciferous    mica- 
schist. 

BERNARDSTON  SEKIES  OF  UPPEK  DEVONIAN.  259 

I'rot'ossor  Daua  says  (18,  p.  381,  note)  that  Pi-ofessor  Hitchcock's 
"later  conclusions  have  been  influenced  by  his  faith  in  the  lithological  test 
of  ereolosfical  ae:e  and  his  unbelief  in  the  existence  of  s'neisslike  metamoi'- 
phic  rocks  of  later  date  than  the  Cambrian;"  which  I  can  not  think  wholly 
just,  since  the  lattei',  upon  his  atlas  map,  classes  the  wholly  gneisslike  band 
upon  the  north  line  of  the  State  and  the  quartzite,  together  with  the  stauro- 
lite-schist — indeed,  all  the  rocks  in  question  except  the  hornblende-schist — 
with  the  Coos  group,  and  places  this  among  the  Paleozoic  rocks  in  his  final 
scheme  at  the  end  of  the  Geology  of  New  Hampshire,  Vol.  II.  The  dis- 
crepancies are,  however,  sufficiently  great  between  the  interpretations  of  the 
two  authors,  and  I  have  placed  in  parallel  columns  their  views  and  my  own 
of  the  true  order  of  succession  of  the  rocks  in  the  area  in  question.  See 
also  the  section  on  page  285. 

1883.  Mr.  Whitfield  (19)  concludes,  from  an  examination  of  the  fos- 
sils, that  the  limestones  may  be  Middle  Silurian;  the  shales  (i.  e.,  the 
thin-bedded,  rusty  quartzite  immediately  above  the  limestone)  were  most 
probably  Middle  Devonian. 

1890.  The  results  reached  by  the  writer  were  published  in  the  Ameri- 
can Journal  of  Science  (20);  but  as  several  errors  unfortunately  escaped 
his  notice,  the  substance  of  the  article  is  reproduced  below. in  a  corrected 
form. 

THE  UPPER  DEVONIAN  AGE   OF  THE  BERIVARDSTOIV  FOSSILS. 

Prof  John  Mason  Clarke  has  been  so  kind  as  to  reexamine  the  fossils, 
and  as  he  is  familiar  with  the  locality  his  conclusions  may  be  considered  as 
settling  the  age  of  the  series  with  a  large  degree  of  probability.  All  the 
fossils  of  the  upper  bed  of  shaly  quartzite  occur  also  in  the  upper  part  of  the 
the  limestone,  and  it  is  not  possible  to  separate  this  continuous  limestone  mass. 

Professor  Clarke  writes  me  as  follows  (January  28,  1895) : 

The  impressions  left  by  the  fossils  are  so  distorted,  obscure,  and  closely  packed 
together  that  a  little  imagination  can  construe  them  into  species  of  all  sorts  of  ages, 
but  I  feel  reasonably  secure  of  the  following  points : 

First.  The  prevalence  of  a  large  spirifer,  with  moderately  strong  dental  plates, 
like  S.  granulosus  Conr.  of  the  Hamilton  group,  or  S.  disjunctus  Sow.  of  the  Chemung. 

Second.  The  presence  of  Microdon,  probably  abundant  among  the  distortions, 
but  recognized  in  a  single  instance.  The  species  is  uncertain,  may  be  Hamilton, 
Ithaca,  or  Chemung. 


260  GEOLOGY  OP  OLD  HAMPSHIEE  COUNTY,  MASS 


Third.  A  well-defined  Palseoneilo,  witli  coarse  surface  striae  (I  obscured  the  im- 
pression somewhat  by  taking  a  squeeze  from  it).  There  are  species  throughout  the 
Middle  and  lower  Upper  Devonian  of  a  similar  character. 

Pourth.  Well-defined  Oamarotcechias,  like  Rhynchonella  sappho  and  B.  congre- 
gata,  too  obscure  for  specific  identification. 

Fifth.  A  recognizable  fragment  of  a  large  Actinopteria. 

Sixth.  The  "tricircled  encrinite"  of  Eaton  and  Vanuxem.  Though  only  a  crinoid 
column,  this  is,  1  think,  the  safest  horizon-marker  visible;  at  least  its  association  with 
the  other  fossils  mentioned  helps  to  a  close  approximation  to  the  age  of  the  fauna. 
Its  stout  calcareous  body  has  often  preserved  it  from  the  distortions  which  have 
wrecked  the  associated  fossils,  and  its  characteristic  expression  as  it  occurs  in  the 
lower  Chemung  and  Ithaca  beds  is  well  reproduced  here. 

Thus  I  believe  we  are  justified  in  assuming  this  fauna  from  the  shaly  quartzites 
to  be  of  Upper  Devonian  age;  no  change  from  the  old  conclusion,  but  a  better  fortified 
opinion. 

DESCRIPTIOlSr  OF  THE  REGION. 

The  terrace  sands  of  the  Connecticut  River  are  narrow  upon  its  western 
side,  where  the  river  crosses  the  State  line,  and  they  continue  with  little 
increase  of  width  for  4  miles  southwesterly,  and  then,  as  they  enter  Ber- 
nards ton,  their  boundary  upon  the  older  rocks  turns  abruptly  west  and  runs 
for  7  miles  a  little  south  of  west,  past  the  village  of  Bernardston  and  along 
the  north  line  of  Greenfield.  (See  PL  IV.)  Bernardston  village  stands 
just  in  the  middle  of  this  line  and  at  the  mouth  of  a  narrow  valley,  up 
which  a  lobe  of  the  alluvial  sands  reaches  northwardly  for  nearly  2  miles. 
On  the  west  this  valley  is  bounded  by  the  high  ridge  of  West  Mountain, 
made  up  of  the  contorted  argillite,  which  stretches  in  a  narrow  band  far 
north  across  Vermont  and  disappears  below  the  river  sands  on  the  north 
line  of  Greenfield,  appearing  again  only  in  the  limited  outcrop  just  west  of 
the  village  of  Whately,  15  miles  farther  south,  and  in  one  newly  discovered 
at  the  mouth  of  Mill  River.  Everywhere  the  slope  of  West  Mountain 
shows  only  the  black  argillite,  except  in  a  single  band  back  of  the  house  of 
Mr.  F.  Williams,  a  mile  north  of  the  village,  where,  apparently  resting  upon 
the  argillite,  occurs  the  fossiliferous  series.  The  section  has  a  width  going 
up  the  hillside  on  the  line  of  dip  of  only  3,445  feet.  The  outcrops  of  the 
argillite  to  the  north  and  south  show  that  there  can  be  only  a  very  limited 
amount  of  the  newer  series  preserved  upon  the  hillside,  while  the  heavy 
accumulation  of  till  generally  prevents  one's  seeing  its  limits  or  its  contact 


4 


>v 


BERNAEDSTON  SERIES  OF  UPPER  DEVONIAN.  261 

upon  the  rock  below.  It  approaches  the  argilhte  quite  closely  upon  tlie 
west,  and  in  the  line  of  strike  can  not  bo  more  than  9,850  feet  long.  Over 
against  West  Mountain  on  the  east,  across  the  narrow  valley  of  Fall  River, 
rises  a  range  of  hills,  bounded  on  the  south  and  east  by  the  ten-ace  sands, 
which  is  composed  of  a  similar  series  of  rocks  in  similar  succession.  The 
principal  difference  between  the  two  is  that  on  the  east  a  dark  hornblende 
rock,  often  massive,  takes  its  place  in  the  series,  while  the  limestone  and 
magnetite  beds  of  the  typical  section  are  present  only  in  traces  or  in  altered 
form,  and  all  the  other  members  are  somewhat  more  metamorphosed. 

Staiu'olite  here  occurs  in  the  schists,  feldspar  crystals  and  biotite  in  the 
quartzites,  and  they  are  thrown  into  complex  folds  and  greatly  faulted. 
They  lie,  in  fact,  along  the  center  of  the  great  syncline  of  the  Connecticut 
Valley,  which  is  an  area  of  maximum  disturbance  of  the  rocks  quite  across 
the  State.  These  discrepancies  become  less  important  when  it  is  noticed 
that  hornblende  exists  in  considerable  quantity  directly  above  the  Williams 
farm  hmestone,  and  the  second  bed  of  the  same  limestone  in  South  Vernon 
is  encased  in  hornblende-schist,  and  several  of  the  hornblende-schist  beds 
can  be  proved  to  be  altered  limestone  beds. 

Across  the  river  in  Northfield  the  white  saccharoidal  quartzite  extends 
to  the  base  of  Northfield  Mountain,  and  is  there  bounded  by  a  north-south 
fault,  while  only  a  single  outcrop  of  schist  is  exposed. 

THE  REIiATION  OF  THE  BERlSrARDSTON  SERIES  TO  THE  ARGILLITE. 

It  was  originally  assumed  by  President  Hitchcock  that  the  argillite 
and  the  schists  of  this  series  were  conformable.  Prof  J.  D.  Dana,^  finding 
the  argillite  about  a  half  mile  west  of  the  limestone  to  have  a  much  higher 
dip,  decided  that  they  were  unconformable  to  and  much  older  than  the 
upper  series,  and  this  conclusion  was  accepted  by  Prof  C.  H.  Hitchcock.^ 
In  tracing  the  distribution  of  the  quartzite,  I  have  given  five  localities  where 
the  boundary  of  the  quartzite  and  argillite  is  well  exposed  (p.  273),  and  I 
could  increase  the  num.ber,  and  in  each  case  there  is  apparent  conformity 
and  a  uniform  passage  from  the  common  argillite  into  argillite  with  minute 
garnets  and  minute  biotite  spangles,  fine-grained  black  quartzite  grading 

'Am.  ,Joar.  Sci.,  Vol.  VI,  3d  series,  1872,  p.  343. 
^Geol.  New  Hampshire,  Vol.  II,  1887,  p.  433. 


262       GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

into  coarser  quartzite,  and  conglomerate.  The  argillite  is  extremely  corru- 
gated and  often  cleaved,  and  observations  of  dip  a  rod  from  the  contact  are 
of  no  value  in  settling  a  question  like  this. 

THE  WI1.LIAMS  FARM  SECTION.    THE  F08SILIFER0US  lilMESTONE. 
PROOF  THAT  THE  WHOLE  SERIES  IS  DEVONIAK. 

The  long  band  of  the  recks  of  the  Bernardston  series  along  the  lower 
slope  of  West  Mountain  has  been  brought  into  its  present  position  by 
extensive  dislocations,  and  is  plainly  cut  off  by  two  transverse  faults  which 
run  approximately  in  the  brook  gorge  north  of  the  limestone  and  in  the 
larger  gorge  of  Fox's  brook  half  a  mile  south.  The  area  between,  contain- 
ing the  fossiliferous  limestone,  is  the  one  here  described.  (See  PL  IV  and 
fig.  15.) 

Passing  up  the  hillside  back  of  Mr.  Williams's  barn,  the  first  bed  and 
the  upper  one  on  the  section  (fig.  16,  p.  264)  is  a  dark  muscov^'te-schist  (1), 
which  is  exposed  in  a  single  small  quarry  and  separated  by  a  depression 
which  runs  with  the  strike,  and  which  I  have  assumed  in  the  section  to  be 
occupied  by  the  same  schists  and  to  have  been  formed  by  their  erosion. 
The  outcrops  are  almost  continuous  across  the  quartzite  (2)  and  the  lime- 
stone (4)  which  follows  to  the  second  outcrop  of  schist,  where  a  similar 
depression  separates  the  latter  from  the  second  band  of  quartzite,  which  I 
have  in  like  manner  supposed  to  be  occupied  by  this  schist. 

Section  of  the  Williams  farm  rocks. 

Feet. 

1.  Garnetiferous  mica-schist 73 

2.  Micaceous  quartzite  and  conglomerate 443 

3.  Magnetite,  maximum 3J 

4.  Limestone 19^ 

Quartzite  concealed  beneath  the  limestone  ( ?). 

Fault. 

v.  Mica-schist 115 

2'.  Quartzite  and  conglomerate,  if  conformable  with  the  mica- 
schist 666 

Argillite. 

(The  beds  below  the  fault  are  a  repetition  of  those  above.) 

The  argillite  (fig.  16,  west  end). — Beginning  nearly  a  mile  northwest 
of  the  Williams  house,  and  just  north  of  the  point  where  the  road  over  West 
Mountain  bends  sharply  west,  a  long  ridge  of  the  typical,  excessively  con- 


BBRNAKDSTON  SERIES  OF  UPPEK  DI<;VONIA]Sr. 


263 


toi"te(l  arg'illite  oxteiids  northerly.  Eastward,  a  drumlin  conceals  its  contact 
with  the  newer  rock.  It  is  probably  a  conformable  contact  of  the  argillite 
and  the  (juai-tzite;  as  I  have  found  it  so  everywhere  in  the  region. 

The  -western  outcrop  of  the  mica-schist  (!'). — Where  the  series  outcrops  for 
the  first  time  after  crossing  the  di'umlin  a  small  area  of  the  mica-schist  of 
this  series  has  recently  come  to  my  notice.     It  is  a  garnetiferous  mica-schist, 


A,  Main  Quarry. 

h.  Thickest  Ma^neiiis.. 

c,  Fxcav^iof?  connecting 
Uinestone  and  Quat'tzitc. 

d,  Excavation  CKposing 
fault  of  Mica-Schist 
against  Limestone. 

e,  Same  as  d. 
if^  Contact  of  Quartzito 

on  Argi/iite. 


ARGILLITE— 
Outcrops  /narked  with  darker  shade. 


Fig.  15. — Map  of  Devonian  rocks  on  the  Williams  farm. 

like  the  more  eastern  ontcrops,  and  it  lies  plainly  in  a  small  syncline  of  the 
qiiartzite  10  rods  south  of  the  western  end  of  a  row  of  great  chestnuts 
which  crown  the  hill. 

The  western  exposures  of  the  qiiartdte  (^'). — The  discovery  of  the  schist 
just  described  makes  plain  the  structure  of  these  quartzite  outcrops  with 
their  western  dip.  As  the  schist  is  in  a  small  syncline,  the  quartzite  makes  a 
corresponding  anticline  on  the  east  of  this  outcrop  of  the  mica-schist.     The 


264 


GEOLOGY  OP  OLD  HAMPSHIRE  COUNTY,  MASS. 


rock  is  dark-gray  quartzite,  at  times  a  conglomerate,  weathering  very  rough, 
with  strike  and  dip  very  irregular  and  uncertain,  with  many  slight  slips 
and  crushings — indeed,  often  completely  brecciated  and  recemented  with 
limpid  quartz.  Locally  it  passes  into  a  black  siliceous  slate  by  the  micro- 
scopical development  of  biotite  and  the  accumulations  of  coaly  matter.     A 


APirct:  lurg^Otsfmlft. 


Fig.  16. — Section  of  Devouian  rocks  from  the  Williams  farmhouse  250  rods  northwest  to  the  sharp  hend  in  the  road 
over  ^\''est  Mountain,  along  the  section  line  on  map,  fig.  15. 

few  scales  of  the  former  mineral  can  be  seen  with  the  lens.  Up  the  hillside 
from  the  limestone  along  the  line  of  dip,  two  small  ledges  of  the  rock  appear, 
as  may  be  seen  from  the  section,  widely  separated  from  each  other  and  from 
the  rocks  above  and  below. 

It  is  not  diificult  to  find  among  tlie  less  crushed  portions  of  each  ledge 


■2 
<o 


\d,; 


^fffidu^fa prove  corjformit/  befireen  limestone,  and  Ousr^zif^. 


IPio.  17. — Section  of  the  "WiUiama  farm  quarry;  an  enlargement  of  the  center  of  iig.  16,  at  a  of  iig.  15. 

pieces  which  agree  exactly  with  the  quartzite  above  the  limiestone,  especially 
that  which  outcrops  a  few  meters  above  the  latter,  and  its  peculiar  appear- 
ance is  largely  due  to  crushing  and  infiltration  of  quartz.     The  same  result 


BERNARDSTOISr  SERIES  OF  UPrER  DEVONIAN.  265 

is  reached  by  examining  the  quartzile  ledges  along  the  strike  north  and 
south  from  this  point  and  comparing  them  with  the  "upper  quartzite." 

Tlie  mica-schist  ivcst  of  flic  limestone  (i'). — This  rock,  like  that  east  of 
and  abt)ve  the  limestone  (1  of  the  section)  is  a  dark,  even-l^edded  musco- 
vite-schist,  so  fine-grained  as  to  be  almost  indistinguishable  from  the  even- 
bedded  varieties  of  the  argillite  below,  with  its  glistening  surface  pitted 
here  and  there  by  minute  hollows  from  which  small  red  dodecahedral 
garnets  have  fallen  out.  It  is  abundantly  marked  by  small  bodies,  which 
appear  much  like  minute  altered  chiastolites  barely  visible  to  the  eye.  It 
occurs  only  at  the  bottom  of  the  slope  just  west  of  the  line  of  excavations 
for  limestone.     (See  "  Petrographical  description,"  No.  14,  p.  291.) 

Fault  between  the  schist  and  the  limestone  (d,  fig.  lb). — The  bed  last 
described  apparently  dips  25°-35°  E.  under  the  limestone,  with  the  strike 
N.  70°  E.  But  just  opposite  and  northwest  of  the  largest  excavation  in 
the  limestone,  under  a  small  apple  tree,  where  the  schist  seemed  certainly 
to  go  under  the  limestone,  and  where  Professor  Dana  and  I  once  dug 
down  and  followed  it  for  6  inches  under  the  limestone,  I  had  excavations 
made  at  a  later  time,  having  doubted  the  reality  of  the  apparent  conforma- 
ble superposition  because  the  bed  of  limestone  rested  on  the  schist  with 
abrupt  transition  and  total  want  of  continuity.  I  found  the  two  rocks  to 
be  faulted  against  each  other,  the  wall  of  the  limestone  bending  under  for 
a  few  inches  and  then  going  down  vertically,  and  the  schists,  so  flat  in  the 
exposures  below,  were  here  crumpled  up  sharply  and  ground  into  shapeless 
masses  against  the  limestone.  I  followed  the  fault  down  nearly  4  feet 
without  finding  the  bottom  of  the  limestone,  but  mingled  in  the  crushed 
schist  I  found  fragments  of  the  chloritic  rock  which  lies  in  the  limestone 
and  is  exposed  in  the  bluff  to  the  north  (fig.  18).  At  a  later  date  I  had 
further  excavation  made,  uncovering  the  northern  bluff,  where  also  the  mica- 
schist  approached  the  limestone  at  its  northern  end,  and  I  exposed  here  a 
zigzag  fault  line  between  the  schist  on  the  west  and  the  black  magnetite- 
pyrite-chlorite-limestone,  and  below  this  between  the  schist  and  the  white 
limestone  itself  (e,  fig.  15).  The  fault  plane  is  nearly  vertical.  The  relation 
of  the  beds  at  this  point  are  made  plain  by  fig.  18  (p.  266). 

The  limestone. — The  limestone,  which  forms  the  center  of  interest  of  the 
section,  is  exposed  in  many  old  pits,  extending  from  the  bluff  overlooking 
the  brook  to  the  largest  opening  overhung  by  birches,  where  the  rock  is 


266 


GEOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 


most  fossiliferous ;  and  the  line  of  outcrops  is  continued  by  more  scattered 
openings  farther  southwest.  It  extends  in  all  about  407  feet  from  northeast 
to  soiithwest — ^that  is,  along  the  line  of  strike.  It  is  for  the  most  part  a 
coarsely  crystalline,  saccharoidal  limestone,  at  times  so  coarse  that  cleavage 
pieces  of  calcite  3  inches  across  can  be  obtained  from  it.  Below,  it  is  in 
thick  beds,  with  stratification  mostly  obliterated,  while  the  upper  portion 
for  about  6^  feet  is  thin-bedded,  finer-grained,  and  micaceous.  The  rock 
contains  some  pyi'ite,  which,  with  the  more  abundant  deposit  of  the  same 
in  the  bottom  of  the  quartzite,  has  been  the  source  of  the  great  amount  of 
porous  limonite  which  fills  broad  veins  and  great  cavernous  spaces  in  the 
limestone.  Its  modem  formation  is  attested  by  the  rootlets,  changed  into 
limonite,  inclosed  in  it. 


Fig.  18. — Section  at  nortli  end  of  limestone,  Williams  farm.    The  two  lower  outcrops  of  quartzite  are  separated  from  the 

rest  of  the  section  by  an  east-west  fanlt. 

To  turn  over  a  mass  of  coarsely  crystalline  marble  and  find  the 
weathered  surface  covered  with  crinoid  stems  or  corals  makes  a  strange 
impression  upon  one.  In  masses  showing  no  trace  of  fossils  these  are 
brought  out  equally  well  in  thin  sections,  and  I  have  even  observed  a 
fragment  of  the  shell  of  a  brachiopod  preserving  the  punctate  structure,  the 
pores  agreeing  closely  in  position  and  measurement  with  those  of  modern 
genera. 

In  the  section,  fig.  17,  all  the  fossils  known  are  assigned  to  their 
proper  horizon,  so  far  as  possible.  I  would  especially  note  the  fact,  to 
which  my  attention  was  first  called  by  Prof.  J.  M.  Clarke,  that  the  line  of 
division  between  the  two  paleontological  horizons  represented  falls  well 


BERNARDSTON  SERIES  OF  UrPER  DEVONIAN.  267 

down  in  the  limestone,  and  that  the  upper  3  feet  of  the  latter  is  thin-bedded 
and  lacks  the  forms  found  below,  while  it  carries  the  peculiar  annulate 
crinoid  stems  found  also  very  abundantly  in  the  quartzite  above. 

The  shaly  limestone  is  in  places  much  fissured,  and  is  cemented  at 
times  with  veins,  one -fifth  to  two-fifths  of  an  inch  wide,  of  a  completely 
granitoid  mixture  of  quartz  and  muscovite,  the  plates  of  the  latter  extend- 
ing quite  across  the  vein,  while  the  cemented  rock  still  shows  abundant 
ciinoid  stems.  The  limestone  contains :  CaCOo,  98.38 ;  FcgOa,  0.62 ; 
SiO,,  1.00. 

The  magnetite  bed. — In  the  largest  opening  under  the  main  groiip  of 
birches  the  limestone  for  the  upper  3  inches  is  impregnated  with  magnetite, 
and  the  quartzite  above  this  is  fossiliferous.  Fifty  feet  north  the  ferruginous 
horizon  swells  out  to  a  thickness  of  3^  feet,  and  is  here  represented  by  a  bed 
of  porous  limonite.  At  the  same  distance  farther  north  it  is  a  bed  of  fine- 
grained magnetite,  often  pyritous,  in  one  place  garnetiferous,  and  3  feet 
thick.  It  is  of  limited  extent,  but  furnishes  blocks  of  ore  not  to  be  distin- 
guished from  Laurentian  magnetites.  Analysis  indicates  phosphorus  as 
well  as  sulphur. 

A  little  farther  north,  where  the  base  of  the  quartzite  is  exposed  over 
the  thickest  magnetite,  it  is  a  dark-gray  quartz-schist,  abounding  in  pyrite, 
much  crushed,  and  having  the  fissures  covered  with  small,  fresh  rosettes  of 
gypsum  crystals  and  with  drusy  crusts  of  a  mineral  of  earlier  formation, 
now  much  decomposed,  which  seems  to  be  prehnite ;  but  owing  to  the  small 
size  of  the  crystals  (one-fifth  of  an  inch)  and  their  altered  state  they  could 
not  be  certainly  determined.  The  form  of  the  crystals  is  peculiar.  It  is  as 
if  each  wei'e  made  up  of  half  a  dozen  long,  square  prisms,  bounded  above 
by  a  dome  and  placed  side  by  side,  producing  a  form  lite  a  section  of  a 
thick  saw  blade  or  the  milled  edge  of  a  coin. 

At  the  point  where  the  magnetite  is  thickest — 3J  feet — I  exposed,  by 
digging,  its  contact  with  the  limestone  below  and  with  the  quartzite 
above,  and  found  it  to  pass  gradually  into  the  white  limestone  below 
and  to  grade  above  into  a  layer,  1  inch  thick,  of  a  compact,  grayish- 
black  rock,  rusting  red  and  glistening  under  the  lens  with  fine  biotite. 
Under  the  microscope  it  proved  to  be  a  granular  limestone.  (See 
"Petrographical  description,"  Nos.  8  and  10,  p.  289.)  The  rock  grades 
into   the   black  pyritous    quartzite  above;    all   the   beds  are    so    entirely 


268       GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

continuous  and  undisturbed  that  it  is  impossible  to  think  of  faulting  or 
any  irregularity  at  the  junction  any  more  than  at  the  opening  farther 
south  under  tlie  birches,  where  the  junction  is  equally  undisturbed.  The 
paleontological  evidence  reenforces  the  stratigraphical  for  the  continuity 
of  the  limestone  and  the  quartzite.  At  its  northern  end,  overhanging 
the  brook  in  the  most  northerly  digging,  the  magnetite  layer  is  a  black 
magnetite-pyrite-chlorite  rock.  (Fig  18,  and  e,  fig.  15).  This  rock  which 
caps  the  limestone  contains  amphibole,  biotite,  chlorite,  a  little  pyrite, 
magnetite,  and  hematite,  and  an  amorphous  mineral  resembhng  serpentine. 
The  biotite  is  very  dark-colored  in  basal  sections,  and  in  places  changes  into 
chlorite  and  passes  at  the  edges  into  the  serpentine-like  mineral.  In  the 
larger  part  of  the  section  the  latter  has  a  fibrous  structure,  with  the  fibers, 
grouped  into  large,  elongate  patches,  at  times  radiate,  and  the  whole 
resembles  a  fine  hornblende-schist.  It  is  of  oil-green  color,  shows  only  in 
patches  a  trace  of  dichi'oism,  and  with  polarized  light  there  is  a  faint 
predominance  of  extinction  at  about  3°  from  the  long  axis  of  the  fibrous 
groups,  which  proceeds  from  the  whole  group;  and  this  is  overlain,  as  it 
were,  by  the  aggregate  polarization  of  the  fine  scales  and  needles  of  the 
ser]^)entine-like  mineral.  An  analysis  made  for  me  by  Mr.  G.  H.  Corey,  of 
the  class  of  '88  in  Amherst  College,  gave:  SiOg,  42.56;  FeA,  44.25;  CaO, 
13.11^99.92.  The  absence  of  magnesia  from  this  analysis  is  puzzling,  as 
the  product  of  decomposition  of  the  hornblende  resembles  serpentine 
strongly.  It  is  possible  that  a  highly  ferruginous  amphibole  has  developed 
in  the  magnetite-calcite  bed,  and  that  this  has  changed  into  a  ferruginous 
mineral  allied  to  chloropal. 

The  eastern  hed  of  quartzite  (3). — Under  the  birches,  as  presented  in  the 
section  (fig.  17),  Sjfeet  of  a  thin,  evenly  laminated,  light-gray  quartz-schist 
caps  the  limestone  and  is  very  rusty,  especially  at  the  base,  and  porous  from 
the  amount  of  pyrite  and  calcite  that  has  been  removed.  Two-thirds  the 
way  up  a  layer  of  about  4  inches  thickness  is  crowded  with  flattened  and 
distorted  casts  of  brachiopods  and  of  annulate  crinoid  stems.  A  large  spirifer 
with  septa  like  S.  disjuncta  is  very  abundant.  Traces  also  of  Rhynchonella 
and  Orthis  are  common,  of  Nucula  and  Platyostoma  rare,  and  the  ringed 
crinoid  stems  are  again  very  common.  The  fossiliferous  part  of  the  bed  is 
of  very  limited  lateral  extent,  and  I  could  trace  it  only  about  10  feet. 

The  next  outcrop,  150  feet  east  and  about  6  feet  above  the  bed  just 
described,  is  a  hard,  gray,  quartzose  conglomerate,  with  white,  flattened  quartz 


BEUNARDSTON  SERIES  OF  UPPER  DEVONIAN.  269 

pebbles  oue-half  to  1  inch  across.  Under  the  microscope  the  rock  is  seen 
to  be  made  up  of  ang-iihir  grains  with  large  cavities  filled  with  water,  con- 
taining spherical,  highly  refringent  globules  with  moving  bubbles.  It  carries 
also  carbonaceous  matter  in  globules,  magnetite,  pyrite,  a  little  hornblende, 
and  inuscovite,  the  latter  forming  the  partings  between  the  pebbles.  It 
resembles  much  more  closely  the  highly  altered  quartzite  described  above 
(p.  263)  than  it  does  the  rest  of  the  quartzite  above  and  below  it.  The 
quartzite  continues  very  compact,  vitreous,  and  unevenly  bedded  for  66  feet 
down  the  hill,  and  in  its  upper  portion  carries  garnets.  It  then  becomes 
thin-laminated,  separating  into  layers  about  1^  inches  thick,  which  are  in 
fi-esh  cross-section  white  to  bluish,  Adtreous  quartz,  and  the  surface  of  the 
plates  is  coated  with  muscovite.  It  is  finely  jointed  and  the  surfaces  of  the 
broad  plates  are  somewhat  warped,  giving  varying  dips.  Higher  up  it  is 
cut  by  great  veins  of  quartz,  and  in  the  last  outcrojD  before  reaching  the 
eastern  outcrop  of  mica-schist  it  is  again  a  compact  quartzose  conglomerate. 
The  strike  of  the  rock  averages  N.  60°  E.,  but  varies  between  N.  25°  E. 
and  N.  70°  E.  The  dip  is  generally  30°-35°  E.,  but  varies  from  25°-50°. 
At  the  large  quarry  a  single  surface  10  feet  square  gave  25°  above  and  42° 
below.     (See  "Petrographical  description,"  No.  9,  p.  289.) 

Conformity  of  the  limestone  and  the  overlying  quarsite. — Since  the  lime- 
stone, the  magnetite  band,  and  the  ferruginous  quartzites  immediately  over- 
lying the  latter  are  visibly  conformable  and  all  contain  the  same  fossils,  as 
several  times  indicated  above,  there  remained  in  this  direction  only  one 
question  unanswered,  namely,  What  is  the  relation  of  the  series  exposed  in 
the  large  quarry  at  the  birches  and  mentioned  in  the  last  paragraph  to  the 
quartz-conglomerate  with  flattened  pebbles,  exposed  150  feet  to  the  east,  and 
thus  to  the  whole  mass  of  the  eastern  quartzite!  The  latter  seems  much  more 
metamorphosed  than  the  quartzite  at  the  quarry,  and  it  might  be  urged  that 
a  fault  intervened  between  the  two.  On  the  other  hand,  the  conglomerate  is 
typical  of  that  extending  from  this  point  northeast  to  South  Vernon  and 
thence  north  nearly  to  Brattleboro,  and  the  exact  proof  of  their  conform- 
ity would  greatly  enlarge  the  value  of  the  limestone  for  fixing  the  age  of 
the  rocks.  For  this  reason  I  had  pits  dug  10  feet  apart  from  the  top  of  the 
rusty  quartzite  to  the  nearest  outcrop  of  the  conglomerate  to  the  east,  and 
found  the  quartzite  apparently  continuous  and  no  indication  of  any  fault 
between  the  two. 


270  GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

As  this  did  not  wholly  settle  the  question,  I  had  a  trench  dug  exposing 
the  ledge  the  whole  distance  from  the  fossiliferous  quartzite  to  the  conglom- 
erate. It  exposed  a  continuous  surface  of  the  black  shaly  quartzite  for  154 
feet  and  conglomerate  for  10  feet,  with  strike  N.  50°  E.,  dip  40°  E.;  each 
layer  dipped  conformably  beneath  the  succeeding  one,  and  all  were  fused 
together  into  a  continuous  stratum,  and  the  possibility  of  any  fault  was 
wholly  excluded.     (See  fig.  16,  p.  264,  and  c,  fig.  15,  p.  263.) 

The  upper  outcrop  of  the  mica-schist  (1). — This  outcrop  occurs  164  feet 
east  from  the  uppermost  outcrop  of  the  quartzite,  in  a  single  small  ridge 
131  feet  long  and  66  feet  wide,  with  strike  N.  48°  E.  (41°-50°)  and  dip 
30°  E.  (25°-34°).     (Fig.  16,  east  end,  and  fig.  15.) 

It  is  a  dark-gray,  fissile  muscovite-schist  splitting  into  thin  slabs.  Its 
surfaces  are  pimpled  with  small  garnets  and  biotite  crystals,  or  pitted  by 
the  cavities  left  when  the  crystals  remained  in  the  adjoining  slab  of  schist; 
and  it  carries  abundantly  small,  dark-brown  biotite  crystals — ^long  prisms 
with  rounded  angles  1.5  by  2.5°"",  placed  generally  with  their  broad 
cleavage  face  at  a  large  angle  to  the  bedding  plane  of  the  rock,  and  there- 
fore visible  only  as  dull-black  lines  on  the  latter  plane,  but  as  shining-black 
scales  when  the  slab  is  broken  across.  In  tracing  the  same  rock  across  the 
valley  it  was  observed  that  the  great  majority  of  the  scales  lie  with  their 
flat  surface  normal  to  the  line  of  strike  and  with  the  longer  diagonals,  here 
greatly  elongated,  parallel  to  each  other  and  in  the  same  plane  with  the 
dip — a  phenomenon  entirely  comparable  with  the  "stretching"  of  gneiss, 
and  indicating  a  pressure  and  an  incipient  structure  at  a  large  angle  to  the 
present  foliation. 

Microscopically  the  rock  shows  exactly  the  same  scaly,  coal-dusted 
mass,  consisting  largely  of  muscovite  plates  irregularly  bounded,  as  does 
the  schist  (1')  adjoining  the  limestone  (d,  fig.  16),  only  on  a  slightly  larger 
scale.  The  biotite  crystals  are  also  bordered  in  the  same  way  by  a  layer 
of  larger  and  purer  muscovitp  scales,  but  not  so  constantly,  nor  is  the  layer 
so  broad  and  regular.  This  produces  the  forms  which  on  the  surface  of  the 
rocks  look  like  minute  chiastolites. 

The  only  microscopical  distinction  between  the  schists  is  in  the  some- 
what larger  size  of  the  constituents  and  a  slightly  greater  clearness  of 
crystalline  textui-e  in  the  upper,  so  that  one  can  affirm  more  certainly  the 
absence  of  any  clayey  matter.     (See  "  Petrographical  description,"  No.  15, 


BEKNAKDSTON  SERIES  OF  UPPER  DEVONIAN.  271 

p.  292.)  Macroscopically  the  upper  schist  is  somewhat  tliicker  bedded  and 
of  more  mieveii  surface.  A  lens  is  hardly  needed  to  see  the  muscovite 
scales  on  the  surface  of  the  slabs,  and  the  biotite  and  garnet  are  conspicu- 
ous and  abundant  accessories,  instead  of  being  only  minute  and,  in  the  case 
of  garnet,  rai*e. 

The  si/ncline  north  of  the  brook  in  the  Williams  pasture. — (See  north  part 
of  map,  fig.  15,  p.  263.)  Within  the  area  just  described  the  rocks  dip  mostly 
to  the  east,  while  north  of  the  brook  the  structure  is  decidedly  different.  A 
section  east  and  west  through  the  woods  shows  a  great  syncline  of  the 
quartzite  in  the  argillite. 

Following  down  the  brook  from  the  limestone  to  where  the  woods 
end,  and  then  skirting  the  latter  for  a  few  rods  north  to  where  the  first 
wood  road  enters  them,  a  little  way  in  and  at  the  first  outcrop  on  the 
south  side  of  the  road  one  comes  upon  a  well-exposed  contact  of  the  argil- 
lite  beneath  and  the  quartzite  above;  strike  N.  20°  E.,  dip  20°  W.;  the 
argillite  flat-fissile,  with  few  chloritized  garnets;  the  quartzite  a  dark-gray 
indm-ated  sandstone,  becoming  coarser  higher  up.  The  two  beds  seem  to 
be  plainly  conformable.  The  argillite  can  be  followed  north  to  a  point  in 
the  bluff  opposite  C.  Frary's  house,  and  has  a  uniform  westerly  dip  beneath 
the  quartzite,  and  on  the  west  of  the  latter  the  argillite  is  found  dipping 
easterly  beneath  it,  though  the  junction  is  covered.  I  imagine  this  syncline 
is  cut  off  on  the  north  by  a  fault  along  the  bed  of  Fall  River,  but  the  rocks 
are  covered  here.  Directly  opposite  the  limestone  across  the  brook  to 
the  north  the  quartzite  contains  dodecahedral  garnets  one-half  inch  across, 
bordered  by  chlorite. 

Tlie  outcrop  along  Fox  BrooJc  south  of  the  Williams  section. — On  the 
road  over  West  Mountain,  behind  the  first  house  after  leaving  the  village, 
there  is  seen  from  the  road  a  bare  bluff  of  blue  till,  and  below  this  is  an 
outcrop  in  the  brook  of  Triassic  sandstone.  Twenty  rods  above  this  the 
quartzite  rests  conformably  upon  the  argillite,  which  contains  a  few  gar- 
nets just  below  the  junction.  It  strikes  N.  60°  E.,  and  dips  20°  E.,  and  the 
boundary  is  thus  pushed  east  by  the  whole  width  of  the  Williams  section, 
though  the  fault  which  separates  them  can  not  be  exactly  located. 


272  GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

DBSCRIPTIOK    OF    THE    RANGE    FROM    BERNARDSTO^T    TO    SOUTH 

TBRNON. 

Directly  opposite  the  Williams  farm  and  200  rods  distant,  on  the 
east  side  of  Fall  Eiver,  begins  a  range  of  low  hills  which  run  northeast 
between  the  two  towns  named  above.  This  range  of  hills  is  backed  on  the 
northwest  by  a  much  higher  range  of  argillite  hills — Bald  Mountain  and 
Pond  Mountain — and  is  bounded  on  the  southeast  by  the  high  terrace  sands, 
through  which  one  large  area  and  many  smaller  islands  of  the  rocks  of  the 
Bernardston  series  emerge.  I  have  called  this  the  West  Northfield  range, 
from  the  town  in  which  it  for  the  most  part  lies.  The  road  running  along 
the  east  side  of  Fall  River  skirts  the  range  at  its  western  end,  and  the  main 
road  from  Bernardston  to  South  Vernon  borders  it  on  the  south  and  east, 
while  the  roads  which  branch  from  tlie  latter  and  cross  the  range  are  named 
from  some  resident  upon  each,  as  given  in  Beers's  atlas  and  as  marked  on 
the  map,  PL  IV. 

The  mapping  of  this  area  was  difficult,  both  because  the  rocks  are  ' 
thrown  into  great  confusion,  many  beds  being  in  places  echeloned  so  that 
the  local  strike  regularly  disagrees  with  the  general  run  of  the  bands,  and 
because  of  the  presence  of  several  large  drumlins  which  effectually  conceal 
the  underlying  rock.  The  intervening  areas  are,  however,  so  entirely  free 
from  drift  up  to  the  very  foot  of  these  hills  that,  were  it  not  heavily  wooded, 
the  region  would  furnish  abundant  outcrops,  and,  as  it  is,  the  fragments  on 
the  surface  can  be  safely  used  to  determine  the  rock  below.  The  series 
wraps  around  the  argillite  and  uniformly  dips  away  from  it,  generally  at 
low  angles,  at  first  south,  and  then  for  a  long  distance  southeast;  then  it 
swings  sharply  round,  crossing  the  State  line  with  dips  a  little  east  of  north, 
making  thus  a  great  bend  to  the  westward  as  it  crosses  the  town  of  Vernon. 
I  have  not  been  able  to  prove  the  existence  of  folds  or  overturns,  and  the 
present  position  of  the  beds  seems  to  be  best  explained  as  the  result  of  very 
extensive  faulting. 

The  argillite. — I  have  assigned  to  the  argillite  the  broad  area  marked 
"Coos"  upon  Professor  Hitchcock's  map  (17,  Atlas),  to  which  he  also  assigns 
the  slates  of  the  Bernardston  series,  because  I  have  found  that  the  boundary 
between  it  and  the  argillite  to  the  west  as  given  upon  that  map  has  no 
justification  in  any  physical  change  in  the  character  of  the  rock  where  it  is 
drawn,  and  the  argillite  can  be  traced  unchanged  up  to  and  dipping  beneath 


BERNAEDSTON  SEKIES  OF  UPPER  DEVONIAN.  273 

the  ([uartzite  next  described.  It  is  true  that  minute  scattered  garnets  and 
very  small  staiu-olites  are  found  sparing-ly  in  the  rock  in  some  places  in  this 
area,  and  these  seem  to  have  been  relied  upon  by  Professor  Hitchcock  in 
making  the  assignment  of  the  rocks  to  the  Coos;  but  the  same  garnets  can 
be  found  at  times  in  the  undoubted  argillite  in  West  Mountain,  and  these 
and  the  same  minute  staurolites  occur  in  the  center  of  the  Whately  argillite, 
and  both  the  minerals  are  very  different  from  their  representatives  in  the 
Coos  group.  Both  in  macroscopical  and  microscopical  structure  the  rock 
remains  quite  constant  up  to  the  quartzite,  and  in  its  finer  grain,  its  darker 
color,  its  excessive  contortions,  and  its  abundant  and  large  quartz  veins  it  is 
well  distinguished  from  the  slates  of  the  higher  series. 

The  very  remarkable  projection  of  the  argillite  into  the  basal  quartzite 
in  Vernon,  in  the  northwest  corner  of  the  Warwick  quadrangle,  is  very 
clearly  made  out  on  the  ground  and  is  very  interesting.  (See  map,  PL  IV.) 
It  is  well  exposed  on  the  high,  bare  hill  north  of  the  last  house  in  West 
Northfield  (M.  Merrill's).  The  argillite  dips  everywhere  outwardly  under 
the  quartzite,  and  is  greatly  contorted  and  crushed  and  filled  with  quartz 
veins  and  combs. 

The  basal  quartzite  and  conglomerate. — The  position  and  extent  of  the 
basal  quartzite  gave  the  first  clue  to  the  complex  stratigraphic  arrangement, 
of  the  series  in  its  eastward  continuation.  Beginning  at  the  point  already 
described  (page  272),  opposite  the  Williams  farm  and  east  of  the  road  to 
East  Mountain  (back  of  "Mrs.  Haley's"  on  the  old  atlas  map),  with  a  strike 
due  east,  it  has  bent  round  to  N.  65°  E.  before  it  goes  under  the  massive 
drumlin  which  lies  east  of  the  river,  and  on  its  emergence  it  is  abundantly 
exposed  with  the  same  strike  along  the  southern  of  the  two  northwest  roads 
mentioned  above,  west  of  Dry  Brook,  especially  soiith  of  A.  G.  Chapin's 
house.  Taking  the  direction  of  this  road  across  the  valley  of  Dry  Brook, 
it  can  be  followed  readily,  with  the  same  strike  and  low  southeast  dip,  and 
physically  unchanged,  through  the  chestnut  woods  northwest  of  the  end  of 
Purple's  blind  road,  east  of  Dry  Brook.  It  crosses  the  first  north-south 
road  in  Northfield  at  a  point  where  a  loop  of  the  brook  is  cut  by  the  road, 
and  gradually  bearing  round  to  the  north  it  passes  the  State  line  with  a 
strike  N.  10°  W.  It  then  makes  a  great  sweep  to  the  east,  turns  sharply 
on  itself,  goes  south  across  the  State  line  for  a  little  way,  and  then  swings 
round  to  the  north  at  the  foot  of  the  high  ground  and  continues  northerly. 

MOW  xxix 18 


274  GEOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 

Back  of  Mrs.  Haley's,  mentioned  above,  tlie  rock  is  an  obscurely- 
bedded  conglomerate  of  quartz  pebbles  in  a  dark  ground  containing  much 
slaty  ma,terial.  The  conglomerate  here  toward  its  base  is  exactly  like  the 
same  rock  west  of.  the  limestone  on  the  Williams  farm,  and  I  have  no  doubt 
that  they  were  formerly  connected  across  the  valley.  Higher  up  the  rock 
is  a  pudding-stone,  with  rounded  quartz  pebbles  up  to  4  inches  in  length, 
but  mostly  1  inch  long;  the  abundant  quartz  sand  and  ground  which  wraps 
around  them  cleaves  into  thick  layers  coated  with  muscovite  scales  and  iron 
rust,  so  exactly  like  the  upper  quartzite  of  the  Williams  farm,  especially  the 
conglomerate  layer,  that  it  is  difficult  to  avoid  the  conclusion  that  they  are 
parts  of  a  single  stratum.  Calculated  upon  its  average  dip  of  20°  the  thick- 
ness of  the  bed  is  400  feet,  which  is  only  a  rough  approximation. 

In  the  field  south  of  A.  G.  Chapin's  house  is  an  interesting  outcrop. 
The  rock  is  here  jointed  with  almost  mathematical  accuracy  into  acute 
rhombs,  the  joint  planes  passing  through  the  quartz  and  quartzite  pebbles, 
and  the  latter  are  finely  compressed  and  indented  one  by  another.  The 
rock  here  carries  garnets  one-fifth  of  an  inch  across.  It  is  unchanged  across 
Dry  Brook  for  a  long  distance  to  the  northeast,  when  it  crosses  the  last 
road;  but  once  over  the  range,  at  a  point  where  the  brook  makes  a  loop 
across  the  road  (near  J.  M.  Pickett's),  the  pebbles  are  flattened  out  into 
thin  disks  resembling  the  small  lenses  of  quartz  common  in  crystalline 
rocks,  making  it  possible  that  they  are  of  secondary  origin — a  possibility 
which  does  not  extend  to  the  range  described  above.  In  the  woods  south- 
west of  this  point  the  rock  in  some  beds  is  in  appearance  a  fine-grained 
biotite-gneiss,  with  large  garnets  surrounded  by  a  broad,  annular,  white 
space,  in  which  the  biotite  is  wanting,  the  iron  being  concentrated  in  the 
garnets.  Farther  north  in  the  band  the  pebbles  grow  smaller,  and  where 
it  crosses  the  State  line  it  is  at  base  a  thin-bedded  biotitic  quartzite; 
higher  up,  a  muscovitic  quartzite.  In  some  layers  the  muscovite  becomes 
abundant  and  wraps  around  pencils  of  quartz,  so  that  the  rock  obtains  a 
rude  columnar  or  ligniform  structure.  It  has  here  an  apparent  thickness  of 
350  feet. 

At  the  point  abeady  mentioned  on  the  grist  mill  road  (at  J.  M. 
Pickett's),  where  the  brook  makes  a  short  loop  across  the  road,  at  the  south 
bridge,  is  a  fine  section  in  a  high  bluff  west  from  the  bridge.  The  con- 
glomerate  strikes   N.  45°  E.  and  grades  downward  thi-ough   50  feet  of 


BEENARDSTON  SERIES  OF  UPPER  DEVONIAN.  275 

quartzite  into  tiue,  micaceous  quartzite,  and  this  into  flat  argillite  with 
minute  transvei'se  biotites.  The  whole  is  well  exposed  and  plainly  con- 
formable. Its  dip  increases  from  22°  at  the  south  end  to  45°  at  the  north 
end,  where  the  upper  portion  of  the  bed  has  this  high  dip,  while  the  lower 
portion  runs  up  on  the  argillite  with  the  low  dip  of  20°.  It  thus  folds 
around  and  dips  away  from  a  great  promontory  of  the  argillite ;  and  it  is 
blackened  in  many  places  by  a  remnant  of  the  argillitic  material. 

All  this  is  well  exposed  just  north  of  the  last  house  before  the  State 
line  is  reached  (at  M.  Merrill's),  and  the  argillite  where  it  is  nipped  by  the 
sharply  bending  quartzite  is  greatly  crushed  and  filled  with  quartz  combs. 
This  boundary  crosses  the  next  road  north — the  old  Bernardston-Vernon 
road — at  a  small  abandoned  house  (two  houses  below  the  schoolhouse) 
where  the  brook  comes  nearest  the  road.  Just  behind  this  house,  in  the 
side  of  the  brook,  is  exposed  a  most  interesting  junction  of  the  conglomerate 
upon  the  argillite.  Commencing  at  a  ruined  dam  perhaps  16  rods  from  the 
house,  we  find  typical  argillite,  which  changes  through  a  few  feet  of 
spangled  schist  into  thin-fissile,  black,  muscovite-quartzite  with  some  thicker, 
highly  crystalline  layers,  and  this  grades  into  a  hig-hly  muscovitic,  very 
vitreous  quartzite,  which  is  at  one  place  a  conglomerate  of  rounded  quartz 
pebbles  2  to  4  inches  long.  This  is  where  the  water  falls  over  a  reef  3  to 
4  feet  high,  2  rods  below  a  wooden  bridge.  Immediately  below  is  a  bed  of 
heavy  hornblende  rock,  massive,  in  places  showing  a  reticulated  structure. 
Masses  of  this  rock  built  into  the  piers  of  a  wrecked  bridge  just  behind  the 
house  show  pebbles  and  contain  also  much  green  mica,  often  quite  coarse; 
it  resembles  the  more  gneissoid  rock  found  over  the  South  Vernon  plain  to 
the  river,  and  classed  by  Professor  Hitchcock  as  Bethlehem  gneiss.  The 
series  strikes  N.  55°  W.  and  dips  45°  E.  The  outcrop  is  continiious  and 
shows  a  gradual  passage  through  a  spangled  argillite  and  fine-grained 
quartzite  into  conglomerate,  often  coarsely  garnetiferous,  the  change  being 
effected  within  50  feet  and  showing  no  trace  of  unconformity.  Many 
masses  of  a  thin-fissile,  pyritous  magnetite  occur  here,  but  the  bed  could 
not  be  found  in  place.  The  magnetite,  green  mica,  and  hornblende  rock 
suggest  a  repetition  in  the  quartzite  of  a  limestone  band,  perhaps  on  the 
same  horizon  as  the  Williams  farm  bed. 

East  of  the  boundary  line  just  described,  across  Vernon  to  the  river, 
the  whole  area  is  underlain  by  the  basal  quartzite  except  where  the  West 


276       GEOLOGY  OP  OLD  HAMPSHIRE  COUNTY,  MASS. 

Nortlifield  schist  series  extends  across  the  State  Hne  west  of  the  village  of 
South  Vernon  and  where,  across  the.  brook,  it  rises  in  the  hill  back  of 
S.  Titus's,  at  which  place  the  road  to  the  Lily  Pond  branches  from  the 
Brattleboro  road.  The  quartzite  dips  for  the  most  part  to  the  east  except 
east  of  the  Lily  Pond,  where  a  minor  fold  of  considerable  size  occurs, 
caused,  by  the  sharp  bend  on  the  State  line,  and  here  the  beds  dip  south. 
Followed  eastward  it  becomes  more  and  more  feldspathic  and  the  muscovite 
is  largely  replaced  by  biotite,  forming  a  completely  gneissoid  rock.  It 
is  here  not  distinguishable  from  the  feldspathic  quartzite  occurring  east  of 
the  West  Northfield  series,  and  described  on  page  282.  (See  "  Petro- 
graphical  description."  Nos.  1-4,  p.  287.) 

TJie  Vernon  limestone. — On  the  Lily  Pond  road,  above  mentioned,  and 
just  east  of  E.  G.  Scott's  house,  occurs  a  band  of  limestone.  It  is  a  coarse- 
granular  limestone,  highly  crystalline,  of  light  color,  containing  some 
garnet,  hornblende,  and  green  mica.  It  contains  what  seem  to  be  distinct 
traces  of  corals  and  crinoids,  and  in  every  way  closely  resembles  the  Ber- 
nardston  bed,  with  which  I  identify  it  without  hesitation.  EsjDecially  do 
the  weathered  surfaces  show  a  peculiar,  conglomerate-like  structure  common 
at  Bernardston.  Large,  rounded  fragments  of  a  fin^-grained,  white  lime- 
stone are  cemented  by  a  coarser  and  more  highly  crystalline  limestone ;  the 
latter  in  large  amount,  as  if  the  rock  had  been  brecciated  by  pressure  and 
the  fragments  then  rounded  by  percolating  waters  and  recemented.  This 
bed  is  exposed  about  30  rods,  and  may  have  a  thickness  of  as  many  feet, 
but  its  boundaries  are  not  well  exposed.  Toward  the  west  it  grades  on  the 
strike  into  a  calcareous  hornblende-schist,  and  above  that,  to  the  south, 
through  an  actinolite-quartzite  into  a  quartzite  abounding  in  large  gariiets 
and  blotches  of  a  greenish  mica,  while  below  it  passes  into  a  very  coarse, 
thick  bed  of  hornblende-schist.  (See  "  Petrographical  description,"  Nos. 
11-13,  p.  290.)  The  whole  series  is  inclosed  in  the  gneissoid  quartzite. 
This  limestone  is  considered  by  Prof  C.  H.  Hitchcock  to  be  an  Archean 
limestone  in  Bethlehem  gneiss.-^ 

The  mica-schist  and  hornUenclic  heels. — Resting  on  the  basal  quartzite  and 
dipping  from  it  with  low  angle  to  the  south,  southeast,  and  east  successively, 
as  it  folds  around  conformably  with  it  in  the  long  distance  from  Bernardston 
to  South  Vernon,  is  a  broad  area  of  mica-schist  with  several  bands — probably 

1  Geology  of  New  Hampshire,  Vol.  II,  1877,  p.  430. 


BEKNARDSTON  SERIES  OF  UPPER  DEVONIAN.  277 

five — of  horubleude  rock,  a  massive  anipliibolite,  and  a  central  band  of 
g-neissoid  quartzite.  From  the  unequal  rigidity  of  these  rocks  they  are 
thrown  into  great  confusion,  and  from  the  similarity  of  the  rock  in  the  sep- 
arate bands  the  tracing  of  them  is  very  difficult.  As  they  are  placed  upon 
the  map  a  greater  regularity  appears  than  exists  in  the  field,  many  bands 
being  made  up  of  the  slightly  shifted  portions  of  what  was  originally  one, 
and  many  minor  faults  being  of  necessity  neglected. 

In  general  the  schist  is  in  its  lower  portions  finer-grained  and  more 
slaty,  with  small  development  of  the  transverse  mica,  without  staurolite,  and 
with  quite  small  garnets,  becoming  above  coarser,  of  rougher  surface,  and 
knotted  with  large  staurolites. 

At  the  south  end,  nearest  the  Williams  farm,  along  the  road  east  of 
Fall  River  and  northeast  of  Bernardston  village,  the  basal  quartzite  dips 
beneath  a  very  fine-grained,  flat-fissile  mica-slate,  which  dips  20°  in  the 
direction  S.  10°  E.,  its  sm-face  sparsely  pimpled  with  small  garnets,  but 
being  without  other  accessories  and  closely  like  the  western  schist  (!') 
of  the  Williams  farm  section.  A  local  bed  of  a  dark,  pyritous  quai'tzite, 
shghtly  homblendic,  is  marked  in  this  band  of  schist,  but  could  not  be 
followed  far  east. 

The  lowest  bed  of  amphibolite  is  followed  by  a  second  band  of  mica- 
slate  exactly  like  the  first,  which  widens  in  outcrop  easterly  and  passes  with 
the  same  dip  and  strike  beneath  a  massive,  dark-gray  to  greenish-black 
amphibolite,  greatly  jointed,  and  this  is  exposed  in  a  broad  area  nearly  down 
to  the  main  road  running  east  from  Bernardston  and  extending  east  to  the 
house  of  S.  J.  Grreen,  100  rods  west  of  the  locality  mentioned  by  Professor 
Dana.^  It  contains  a  central  band  of  dark  limestone,  at  times  a  foot  thick. 
The  amphibolite  is  capped  by  a  thin  layer,  never  more  than  3  feet  thick,  of  a 
shining-white,  arenaceous  mica-schist,  with  scattered  scales  of  biotite,  and  a 
similar  layer  was  found  to  cap  a  similar  hornblende  rock  in  so  great  a  number 
of  instances  between  this  point  and  South  Vernon  that  it  attracted  particular 
attention.  This  white  layer  was  found  to  pass  in  every  case  up  into  the 
common  dai'k-gray  mica-schist,  and  to  differ  from  it  onl)^  in  the  entire  absence 
of  coaly  matter  and  magnetite ;  and  it  seems  possible  that  the  former  may 
have  been  discharged  by  the  ferruginous  matter  of  the  hornblendic  band 
adjacent;  that  is,  the  organic  matter  may  have  been  employed  to  reduce 

'Am.  Jour.  Sci.,  3d  series,  Vol.  VI,  1873,  p.  342. 


278 


GEOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 


4'WJSM/^^'ff 


M 


fjf 


the  iron  oxides  to  tlie  soluble  form  in  which  they  were  concentrated  in  the 
limestone  bands  as  a  preliminary,  to  their  change  to  amphibolite.     It  is, 

however,  wanting  below  the  hornblendic  bands,  which 
rest  directly  on  the  dark-gray  and  finer  mica-schist. 
This  makes  it  probable  that  none  of  the  hornblendic 
bands  are  overturned,  though  overturn  may  possibly 
have  j^receded  the  final  metamorphism. 

In  places  the  passage  of  the  amphibolite  into  the 
mica-schist  is  by  alternate  bands  and  thin  lenses  of 
the  two  rock  varieties,  and  the  passage  beds  may  be 
3  or  4  feet  thick.  This  is  more  like  the  jDassing  of 
one  sedimentary  layer  into  another  than  like  the  con- 
tact of  an  eruptive  on  a  schist. 

The  schists  of  the  area  just  described  are  cut  off, 
going  eastward,  by  a  great  drumlin,  though  the 
quartzite  can  be  followed  by  its  north  end.  Beyond, 
one  finds  sections  which  expose  the  whole  thickness 
of  the  schists  and  amphibolite  bands. 

They  are  best  studied  in  the  area  east  of  the 
Purple  blind  road  (see  map,  PI.  IV,  and  fig.  19  for 
section,  and  "  Petrographical  description,"  Nos.  16-21, 
p.  293),  where,  commencing  in  the  chestnut  woods 
northeast  of  the  end  of  the  road,  at  the  basal  con- 
glomerate (a,  fig.  19),  we  2Dass  south  over  a  broad 
area  of  the  lowest  mica-schist  (6),  broad  because  of 
the  low  dip,  and  come  upon  the  lowest  amphibolite 
(c),  a  band  about  13  feet  thick,  here,  as  always,  quite 
feiTuginous  and  pyritous.  Fifty  feet  beyond  there  is 
a  second  bed  of  the  hornblendic  rock  (cC)  like  the  first, 
and  both  are  capped  by  the  white  mica-schist  layer 
described  above.  Farther  on  66  feet,  at  the  top  of 
the  ridge,  near  a  large  chestnut  tree  conspicuous  in 
the  open  field,  there  is  a  third,  i-udely  foliated  layer 
of  amphibolite  (e),  thicker  than  the  others.  This  is 
capped  by  a  bed  3  feet  thick  of  a  rusty  limestone  (/), 
carrying  abundantly  cinnamon-colored  garnet  in  large,  shapeless  masses 
and  light-green  pyroxene,  and  by  a  thin  band  of  quartzite.      The  tlu-ee 


peajpi/i/i)  o/djryWM' 


h.  « 


■■k 


BERNAKDSTON  SERIES  OP  UPPER  DEVONIAN.  279 

beds  of  iiinpliibolite  mentioned  are  repi'esented  as  one  on  the  map,  as  they 
are  near  together,  and  the  nortlierly  skipe  on  which  they  appear  approxi- 
mates their  outcrops  still  more.  A  long  slope  follows,  with  scanty  outcrops 
of  mica-schist  (,(/),  still  fine-grained  and  without  staurolite,  but  with  one 
small  bed  of  amphibolite  (Ji),  and  at  its  foot  succeeds  a  heavy  bed  of  horn- 
blendic  rock,  about  66  feet  thick,  which,  by  the  quite  abundant  devel- 
opment of  feldspar,  is  in  large  part  a  complete  quartz-diorite-schist  (i). 
Except  for  the  appearance  of  feldspar  in  small,  irregular,  white  spots,  it 
does  not  deviate  from  the  usual  type  of  the  hornblendic  rock  of  the  area. 
It  is  followed  almost  immediately,  though  the  exact  contact  could  not  be 
found,  by  a  bed,  about  50  feet  thick,  of  a  fine-grained  granitoid  quartzite 
(A;).  This  is,  indeed,  in  its  whole  extent  a  complete  granitoid  gneiss,  never 
fissile,  and  faintly  foliated  only  by  the  parallel  arrangement  of  the  biotite, 
or  wholly  lacking  this  even,  and  becoming  a  fine-grained,  tough,  granite- 
like rock,  largely  feldspathic  and  with  many  striated  feldspar  cleavage 
surfaces  and  light  gray  from  the  small  amount  of  the  biotite.  It  can  be 
followed  for  a  long  distance,  breaking  off  against  a  fault  in  the  northeast 
direction  and  going  southwest  across  Dry  Brook.  Its  place  between  the 
two  heavy  hornblendic  bands  then  seems  to  be  taken  by  a  very  fine- 
grained, massive  quartz  rock,  with  abundant  fine  scales  of  muscovite  and 
with  large,  round  plates  of  biotite  set  at  every  angle.  It  appears  again 
farther  northeast,  at  the  last  road  across  the  range,  and  can  be  followed 
thence  continuously  over  the  high  hill  west  of  South  Vernon  station  and 
across  the  plain  in  Vernon,  trending  here  directly  toward  the  point  where 
the  road  to  Vernon  goes  beneath  the  railroad.  It  is  unlike  the  basal  quartz- 
conglomerate  on  the  west  and  the  feldspathic  quartzite — to  be  described — on 
the  east,  and,  conforming  in  dip  and  strike  with  the  mica-schist  and  making 
all  the  cm-ves  with  it,  it  seemed  to  me  for  a  long  time  that  it  must  be  looked 
upon  as  a  separate  band  in  the  mica-schist  and  could  not  well  be  derived, 
by  folding  or  faulting,  from  the  other  quartzite.  On  noting,  however,  that 
all  the  beds  grow  more  metamorphosed  and  more  feldspathic  as  they  go 
east,  and  that  in  nearly  every  case  the  eastern  bands  of  quartzite  are 
brought  up  by  faulting  and  can  be  proved  to  be  the  same  as  the  basal 
quartzite,  it  has  seemed  to  me  most  probable  that  this  band  has  been 
brought  up  in  the  same  way  and  is  identical  with  the  basal  quartzite.  It  is 
lithologically  transitional  between  the  quartzose  conglomerates  farther  west 
and  the  feldspathic  quartzites  farther  east. 


280       GEOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 

This  interpretation  reduced  the  number  of  the  hornblendic  bands  in 
the  schists  to  4  or  5,  in  place  of  8  or  9,  and  this  makes  the  structure  of  the 
whole  region  much  more  intelligible. 

On  the  section  line  the  quartzite  band  is  followed  by  a  heavy  bed  (100 
feet)  of  a  dark-gray  mica-schist  (I),  much  coarser  than  the  beds  below  and 
carrying  abundantly  transversely  placed  biotite,  small  garnets,  and  large 
stau.rolite  crystals,  the  latter  in  single  crystals  and  in  twins  according  to 
both  the  common  laws.  This  greater  coarseness  of  the  texture  and  the 
great  abundance  of  staurolite  in  the  upper  beds  of  the  mica-schist  are  the 
rule  through  the  whole  length  of  the  range,  and  militate  against  any  attempt 
to  make  out  repetitions  in  the  series  now  gone  over.  This  band  contains 
one  bed,  and  is  capped  by  another  heavy  bed,  of  massive  amphibolite-  (m), 
65  to  80  feet  thick,  which  rises  in  a  prominent  ridge  overlooking  an  isolated 
house  (W.  Sondin's),  and  is  followed  by  one  more  repetition  of  mica-schist 
(n)  and  by  a  great  bed  and  one  or  more  smaller  beds  of  schistose  amphibo- 
lite (o)  before  a  fault  is  reached.  Beyond  this  a  broad  area  of  feldspathic 
quartzite  {p) — to  be  desci'ibed  later — continues  to  the  railroad  at  the 
northwest  corner  of  Gill.  If  the  section  is  extended  across  Grass  Hill 
to  the  Connecticut  River  it  cuts  first  a  broad  continuation  of  this  upper 
quartzite,  followed  by  a  complete  repetition  of  the  mica-schist  series 
with  five  hornblendic  bands,  one  feldspathic,  the  eastern  sloping  down  the 
hillside  from  the  Mount  Hermon  School  buildings  to  the  river,  and  thus 
covering  a  large  area. 

Sections  carried  across  the  area  anywhere  from  the  quartzite  base  south- 
eastward give  substantially  the  same  succession  as  that  detailed  above, 
only  for  a  distance  east  of  this  line  there  is  a  longitudinal  fault  and  a  repe- 
tition of  the  beds;  so  that,  starting  from  the  same  point  as  the  one  chosen 
for  the  beginning  of  that  line  and  going  directly  east  to  the  sawmill  on  the 
South  Vernon  road,  one  passes  nine  distinct  hornblende  bands,  and  in  almost 
every  case  each  band  is  found  capped  by  the  whitish  schist  described  above. 
Also  along  the  State  line  and  for  a  distance  north  and  south,  either  by  the 
thinning  of  the  beds  of  mica-schist  or  by  the  slipping  of  the  hornblendic 
bands  over  them,  the  latter  are  usually  approximated,  the  three  bands  below 
the  middle  band  of  the  quartzite  coming  into  close  proximity  to  one  another 
and  to  the  basal  quartzite.  The  latter  is  separated  by  a  broad  mica-schist 
valley  from  a  prominent  hornblende-rock  ridge  just  in  the  east  edge  of  the 


BEKNAKDSTON  SERIES  OF  UPPEK  DEVONIAN.  281 

woods  looking  down  on  South  Vernon,  which  is  subdivided  by  only  very 
thin  layers  of  schist.  Still  farther  east,  in  the  large  pasture  above  the  South 
^\'rnon  Hotel,  the  beds  are  greatly  faulted,  as  indicated  upon  the  map. 
Here  pseudoniorphs — biotite  after  staurolite — occur  and  show  well-formed 
twins,  and  a  tourmaline  granite  containing  coarse  blue  orthoclase  cuts  the 
schist  and  makes  it  gneissoid. 

It  illustrates  the  abundant  faulting  of  the  region  that  at  the  two  short 
railroad  cuts  in  these  beds  there  are  in- each  case  two  marked  faults,  bring- 
ing quite  distant  beds  into  contact.  Just  south  of  the  South  Vernon  station 
nearly  horizontal  mica-schist  is  faulted  on  the  north  against  a  dike-like  block 
of  massive  amphibolite  about  33  feet  wide,  and  on  the  south  an  equally 
distinct  east-west  fault  line  separates  the  latter  rock  from  the  feldspathic 
quartzite,  also  nearly  horizontal.  At  the  next  cutting,  3  miles  farther^ 
south,  near  where  the  road  crosses  the  railroad,  one  band  of  the  massive 
amphibolite  is  pushed  over  another,  and  the  quartzite  over  both,  so  that 
they  have  a  common  dip  of  25°,  S.  65°  E.;  but  the  fault  planes  are  dis- 
tinctly visible,  and  both  the  hornblende-rock  bands  are  capped  by  the 
whitish  schist  layer  which  marks  their  transition  into  the  common  mica- 
schist. 

The  type  of  the  amphibolite  or  hornblende  rock  as  seen  in  the  area 
described  above  and.  in  many  bands  stretching-  across  the  country  to  South 
Vemon — a  type  from  Avhich  there  is  little  variation — is  a  dark-gray  to  black, 
fine-grained,  wholly  massive  rock,  resembling  so  exactly,  especially  in  its 
jointing,  an  intrusive  diorite  that  it  was  connected  with  the  Mesozoic 
diabase  in  the  first  work  of  President  Hitchcock,  and  at  its  occurrence  at 
the  South  Vernon  station,  where  it  is  faulted  between  mica-schist  and 
quartzite,  it  was  called  trap  by  so  experienced  an  observer  as  Prof.  C.  H. 
Hitchcock,  in  his  latest  work  on  the  area.^  The  hornblende  is  generally 
arranged  in  radiated  fibrous  tufts  just  visible  with  the  lens,  which  aid  in 
giving  the  rock  its  great  toughness.  It  is  not  prone  to  weathering  and 
stands  up  generally  in  long  ridges,  the  schists  having  been  considerably 
lowered  on  either  side  of  it,  but  at  the  railroad  cutting  in  South  Vernon  the 
fissures  were  coated  with  an  abundant  deposit  of  calcite  and  pyrite.  (See 
"Petrographical  description,"  Nos.  17-20,  p.  293.) 

»Geol.  New  Hampshire,  Vol.  II,  p.  438. 


282  GEOLOGY  OP  OLD  HAMPSHIEE  COUNTY,  MASS. 

Because  of  its  position  in  the  hollows  between  the  hornblendic  ridges 
the  mica-schist,  which  really  occupies  more  of  the  surface  than  the  former, 
seems  on  casual  inspection  to  be  of  subordinate  extent  and  importance. 

The  thickness  of  the  beds,  calculated  on  the  average  dip  of  22°,  is: 
quartzite,  350  feet;  mica-schist,  370  feet;  hornblende  rock,  508  feet;  which 
is  certainly  far  too  large  judging  from  the  long  line  of  outcrops  farther 
noi'theast,  and  it  is  probable  that  each  is  partially  repeated  several  times  by 
cross  faults. 

I  have  elsewhere  suggested  that  amphibolite  beds  of  this  type  are 
generally  derived  from  limestone,  and  in  fact  the  hornblende  bands  are 
still  locally  quite  rich  in  carbonates.  At  the  locality  first  described  above, 
just  east  of  Fall  River,  the  broad  amphibolite  baud  contains  layers  of  lime- 
stone an  inch  thick;  and  farther  northeast,  at  a  large  chestnut  tree  east  of 
the  end  of  the  Purple  blind  road,  there  occurs  in  the  same  association  a  bed 
nearly  a  meter  thick  of  impure  limestone  carrying  garnet  and  pyroxene. 
The  development  of  hoi'nblende  at  the  upper  surface  of  the  crinoidal  bed 
has  been  detailed  above,  and  the  large  development  of  hornblende  in  the 
quartzite  surrounding  the  limestone  in  South  Vernon  points  in  the  same 
direction. 

THE   FELDSPATHIC   QUARTZITE. 

Reserving  the  question  of  the  identity  of  this  rock  with  the  basal  con- 
glomerate, I  may  first  call  attention  to  its  curious  distribution  as  shown  on 
the  map,  PI.  IV.  It  occupies  a  broad  area  along  the  eastern  border  of  the 
schist  series  described  above,  everywhere  dips  away  from  it  to  the  east- 
ward with  apparent  conformity,  and  makes  the  same  folds  with  it  all  the 
way  from  the  State  line  south  to  the  point  where  the  main  South  Vernon- 
Bernardston  road  crosses  the  railroad,  even  swinging  round  to  a  north-south 
strike  with  the  schists.  Beyond  this  point  it  occupies  a  broad  area  stretching 
from  the  railroad  across  to  the  Purple  blind  road,  east  of  Dry  Brook,  and 
is  plainly  separated  from  the  schists  on  the  north  by  a  curvilinear  fault- 
Thence  it  continues  in  a  broad  band  southeastward  a  long  distance  and 
can  be  followed  in  scattered  outcrops  across  the  sand  plains  into  the  town 
of  Gill.  Beyond  Dry  Brook  it  seems  to  regain  its  conformity  with  the 
schists.  Across  the  narrow  neck  by  which  the  West  Northfield  sands  join 
those  of  Bernardston  the  same  quartzite  reappears  in  the  northwest  shoulder 


BBRKARDSTON  SERIES  OF  UPPER  DEVONIAN.  283 

of  Grass  Hill,  and  is  ap[)areutly  coatiuuous  under  the  sands  with  the  larger 
area  west  of  the  railroad.     It  dips  under  the  hornblende  rock  to  the  east. 

It  is  everywhere  a  fiue-grained,  light-gray,  fissile  quartzite,  with  small, 
fresh  feldspar  crystals  porphyritically  disseminated  in  it,  often  quite  abun- 
dantly. These  reach  1-2™™  in  cross-section,  and  are  often,  but  not  always, 
striated.  They  ai'e  much  larger  than  the  quartz  grains,  and  often  have  sharp 
crystalline  outlines.  (See  "  Petrographical  description,"  Nos.  6  and  7,  pp. 
288-289.) 

In  the  area  south  of  the  great  fault  at  the  Purple  blind  road,  and  far  west 
from  this  area,  the  rock  is  marked  by  an  abundance  of  grains  of  lavender 
quartz  included  in  it,  which  appear  to  have  come  from  the  pre-Cambrian 
gneiss  of  the  Green  Mountains,  as  I  have  found  it  characteristic  of  the 
Washington  gneiss  in  western  Massachusetts.  Muscovite,  so  abundant  in 
the  lower  quartzite,  is  wholly  wanting;  rarely  a  small  amount  of  biotite  in 
fine  scales,  or,  at  one  outcrop,  of  hornblende  in  scattei'ed  needles,  appears. 

The  dips  of  the  rocks  and  of  the  slates  below  are  so  low,  and,  with  the 
strikes,  vary  so  rapidly  and  irregularly  within  narrow  limits,  that  T  am  left 
in  slight  doubt  as  to  the  exact  conformity  of  the  two  for  any  long  distance. 
Along  the  line  of  junction  for  2  miles  north  or  south  from  the  northern 
road  over  the  range  no  contact  of  the  two  could  be  found,  but  in  the 
whole  distance  they  seem  to  be  exactly  conformable  and  to  have  shared  all 
minor  disturbances;  for  instance,  although  the  rocks  are  tilted  so  that  they 
strike  N.  65°  E.  and  dip  40°  SE.,  they  have  also  been  subjected  to  an  east- 
west  thrust,  as  is  seen  on  a  large  scale  farther  south,  so  that  small  portions 
placed  irregularly  among  the  rest  have  a  north-south  strike,  which  is  shared 
by  both  the  schists  and  the  quartzite. 

The  basal  conglomerate,  often  blackened  by  argillitic  material,  is  a 
rock  of  very  different  habit  from  this  fine-grained,  biotitic,  feldspathic  quartz- 
ite; but  the  description  above  given  of  the  passage  of  the  beds  across  Ver- 
non indicates  that  the  former  passes  into  the  latter  eastward  beneath  the 
schists,  and  is  then  brought  up  by  a  fault  along  the  eastern  base  of  the 
schist  series  and  in  places  thrust  over  the  latter  in  apparent  conformity. 
The  fault  line  must  be  an  exceedingly  tortuous  one,  and  the  Mount  Her- 
mon  series,  on  the  east  of  this  line,  must  be  a  repetition  of  the  West  North- 
field  series.  The  former  series  stretches  from  Otter  Pond  Brook,  in  Gill,  to 
Mount  Hermon,  and   contains   the   same  succession  of  mica-schists  and 


284       GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

ampliibolite.      The  southern  band  of  the  latter  rock  has  a  broad  lateral 
extent,  because  its  dip  coincides  with  the  slope  of  the  hill. 

THE  BEBNARDSTON  SERIES   EAST   OF  THE  CON^TECTICUT. 

The  adjoining  area  east  of  the  river  in  Northfield  is  unfortunately  so 
covered  by  the  terrace  sands  that  only  few  outcrops  appear.  I  think  that 
the  rocks  of  the  Bernardston  series  find  their  eastern  limit,  through  the 
whole  length  of  Northfield,  Erving,  and  Montague,  at  the  foot  of  the  high 
ground  which  bounds  the  Connecticut  Valley  on  the  east;  that  it  ends  with- 
out any  marked  shore  deposits,  but  with  great  crushing  of  the  fine  quartz- 
ite,  probably  on  a  fault  of  great  magnitude  and  extent;  and,  finally,  that  the 
quartzite-schists  and  ampliibolite,  which  succeed  to  the  east  in  the  North- 
field  hills,  though  presenting  some  points  of  similarity  with  the  Bernardston 
rocks,  are  to  be  associated  rather  with  the  series  which  lies  west  of  the 
argillite  and  which  is  presumably  older. 

Thequartzite  in  Northfield. — North  of  this  village  a  porphyritic  quartzite 
identical  with  the  eastern  band  in  the  West  Northfield  range  crops  out  along 
the  eastern  edge  of  the  high  terrace  sands,  but  is  immediately  followed  on 
the  east  by  an  older  series,  mentioned  above.  It  is  much  brecciated,  and 
abundantly  cemented  by  hematite.  It  appears  also  in  the  brook  bottoms; 
and  just  over  the  line  in  Winchester  a  shaft  has  been  sunk  a  hundred  feet 
in  it  for  lead,  which  appears  very  sparingly  in  narrow,  interrupted  fissures  a 
few  millimeters  wide,  associated  with  barite  and  fluorite  in  equally  small 
quantities,  and  at  the  bottom  containing  beautiful  druses  of  pale-yellow, 
saddle-shaped  dolomite  crystals.  Below  the  surface  the  quartzite  is  snow- 
white,  but  otherwise  unchanged.  The  rock  is  a  hard,  white,  saccharoidal 
sandstone,  regularly  porphyritic,  with  small,  clear  feldspars  in  stout  rectan- 
gular cross- sections,  for  the  most  part  striated  and  plainly  of  secondary 
growth,  since  they  inclose  sand  grains.  It  is  here  everywhere  massive. 
(See  "  Petrographical  description,"  No.  5,  p.  288.)  Outcrops  are  seen  in  all 
brook  beds  in  the  northern  part  of  the  town,  and  it  approaches  nearest  to 
the  older  series  in  a  lane  running  east  from  the  L.  A.  Moody  homestead  and 
along  the  Winchester  road.  It  is  here  greatly  brecciated  and  full  of  quartz 
and  hematite  veins.  On  the  east  of  the  boundary  line  several  bands  of  the 
older  series  abut  obliquely  against  this  line,  so  that  the  quartzite  on  the 
west  rests  in  manifest  discordance,  due  either  to  unconformity  or  to  faulting 
of  the  quartzite  against  the  older  series. 


BERNAIiUSTON  SEEIES  OF  Uri'EK  DEVONIAN. 


285 


The  mica-schist  in  NorthJiehJ. — p]ast  of  the  river  only  a  single  limited 
outcrop  of  mica-sohist  occurs,  lialf  a  mile  below  the  village,  just  opposite 
Grass  Hill  and  "200  rods  from  the  nearest  outcrop  of  hornblende  rock  on  the 
west  side  of  the  river.  It  agrees  in  texture  with  the  lowest  beds  of  schist 
on  the  west  of  the  Connecticut,  is  fine-grained,  and  carries  few  accessories. 
It  abounds  in  flattened  ca%'ities,  which  seem  to  be  the  obscure  traces  of  fossil 
shells,  but  they  are  wholly  indeterminable,  if,  indeed,  they  be  of  organic 
origin  at  all.  Upon  the  joint  faces  are  abundant  weathered  crystals  of  a 
flesh-colored  zeolite,  apparently  chabazite.  The  exact  locality  is  by  the 
brook  crossing  at  a  mill  pond  near  the  house  of  A.  Billings. 

THE  ORIGINAL  CHARACTER  OF  THE  SERIES  AKD  ITS  METAMORPHISM, 

The  section  below  seems  to  me  to  represent  the  succession  of  the  beds 
mider  consideration,  the  newest  above. 


Upper  Devonian : 


Mica-scliist  series . 


Quartzite  series , 


Upper  Silurian: 


Beds  of  the  Bernardston  series. 


1.  Mica-schist. 

2.  AmpMbolite. 

3.  Mica-schist. 

4.  Amphibolite. 

5.  Mica-schist. 

6.  Amphibolite. 
I    7.  Mica- schist. 

8.  Quartzite. 

9.  Amphibolite  and  magnetite,  local,  derived  from  the 

limestone. 

10.  Limestone,  with  fossils. 

11.  Amphibolite,  derived  from  the  limestone. 

12.  Quartzite-conglomerate. 


13.  Leyden  argillite. 

14.  Conway  mica-schist. 

Originally  heavy  beds  of  shale  (13)  were  followed  by  a  great  series  of 
feldspathic  sandstones  and  conglomerates  (12-8),  which  contained  a  band 
of  crinoidal  limestone,  with  here  and  there  a  local  development  of  iron  ore 
near  its  surface.  Above  this  was  an  extensive  series  of  shales  (7-1)  with 
several  intercalated  beds  of  impure  limestone.  The  first  series  has  changed 
into  a  crumpled  and  cleaved  phyllite,  to  which  the  name  argillite  has  been 
for  a  long  time  applied.     The  second  series  has  passed  through  all  the 


286  GEOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 

changes  to  a  g-neiss  so  complete  that  Professor  Hitchcock  insists  on  associ- 
ating it  with  the  Bethlehem  gneiss — quartzite  with  flattened  pebbles,  mus- 
covite-quartzite,  biotite-quartzite,  feldspathic  quartzite,  often  porphyritic, 
and  complete  biotite-gneiss,  often  becoming  chloritic  from  superficial  change. 

The  limestone  has  become  most  coarsely  crystalline  and  the  lime  and 
iron  have  been  carried  far  out  into  the  quartzites  above  and  below,  to  form 
amphibolites  and  complex  hornblende-chlorite-pyi-ite  rocks.  The  iron  ore 
forms  a  bed  of  magnetite  or  a  magnetite  rock,  probably  precipitated  as 
limonite  at  the  surface  of  the  limestone  in  the  earlier  stages  of  change,  and 
then  metamorphosed  to  magnetite  later. 

The  upper  series  is  changed  to  complete  mica-schists,  spangled  with 
transverse  biotite  crystals,  often  loaded  with  garnets  and  staurolites,  while 
the  limestone  beds  are  changed  from  the  surface  toward  the  center  into 
amphibolite  beds,  abstracting  the  iron  from  an  adjacent  band  of  the  shales. 

The  dips  are  all  to  the  east  and  the  beds  are  several  times  repeated  by 
monoclinal  faulting,  and  with  each  reappearance  of  the  quartzite  it  is  finer- 
grained  and  more  feldspathic. 

The  series  has  a  slight  pitch  to  the  south,  so  that  in  Vernon  the  whole 
upper  series  tapers  northward  and  disappears;  and  then  in  going  east- 
ward from  the  argillite  we  pass  from  the  more  quartzose  conglomerates 
through  muscovite-  and  biotite-quartzite  to  complete  gneisses,  as  in  the 
successive  reappearances  farther  south. 

The  most  abundant  and  characteristic  fossils  are  Chemung  with  several 
Hamilton  forms,  so  that  the  limestone,  magnetite,  and  the  base  of  the  quartz- 
ite above  the  limestone  may  be  placed  with  certainty  near  the  base  of  the 
Chemung.  That  the  whole  series  must  go  together  is,  I  think,  clear  from 
the  map  and  the  preceding  discussion.  The  suggestion  of  Professor  Hitch- 
cock that  the  limestone  was  bounded  on  both  sides  by  faults^  proves  true 
for  the  west  side,  but  it  is  not  true  for  the  east  side,  and  the  important 
deduction  made  by  him  that  the  limestone  was  much  newer  than  all  the 
surrounding  rocks  is  also  disproved.^ 

'Am.  Jour.  Sci.,  3d  series,  Vol.  XIII,  1877,  p.  315. 

^Professor  Hitchcock  informs  me  by  letter  of  November  22,  1890,  that  he  did  not  speak  of  two 
faults,  as  implied  above,  but  held  that  the  limestone  was  newer  than  the  quartzite  and  infolded  in  it. 
A  reference  to  the  article  above  cited  proves  that  no  mention  is  made  of  faults,  and  I  am  at  a  loss  to 
explain  how  I  came  to  refer  this  opinion  to  Professor  Hitchcock  when  the  above  paragraph  was  printed 
by  me  in  the  American  Journal  of  Science  in  October,  1890,  p.  374.  That  the  limestone  is  newer  than 
the  quartzite  is,  however,  clearly  untenable. 


BERNARDSTON  SERIES  OF  UPPER  DEVONIAN.  287 

The  argillite,  though  the  oldest  rock,  is  least  metamorphosed;  it  is 
crumpled  and  cleaved  with  dull  surfaces  and  is  full  of  coal  grains  and 
kai)liu,  in  its  most  eastern  exposures  showing  minute  pustules  on  its  slaty 
surfaces,  and  at  last  developing  garnet  and  biotite  in  some  abundance.  In 
the  western  exposures  of  the  Bernardston  mica-schist  series  kaolin  could 
scarcely  be  detected,  and  biotite,  garnet,  and  staurolite  were  quite  abund- 
ant but  almost  microscopic,  while  farther  east  the  surfaces  show  clearly  the 
muscovite  sheen  and  the  above  accessories  are  abundant  and  large.  In  the 
Conway  mica-schist,  which  lies  below  the  argillite,  the  separate  muscovite 
scales  are  clearly  visible  to  the  eye,  and  the  same  accessories  occur  still 
larg'cr  and  with  a  very  different  and  much  more  complex  structure. 

petrographicaij  description. 

the  quartzite  series. 

1.  Micaceous  quartzite  from  South  Vernon,  roadside  east  of  Lily  Pond, 
near  the  town  line.  A  rather  thin-foliated  and  somewhat  fine-grained  gneis- 
soid  rock,  the  broad  and  abundant  films  of  a  green  micaceous  mineral  sepa- 
rating the  white,  fine-granular  quartzose  ground.  This  is  the  Bethlehem 
gneiss  of  Prof  C.  H.  Hitchcock.'^  In  section  the  quartz  ground  is  plainly 
clastic.  The  abundant  scales  of  biotite  are  rarely  brown  at  center,  but  mostly 
changed  to  green,  and  are  much  stretched,  wrinkled,  and  raveled  out. 

2.  Another  specimen  from  the  same  region,  but  nearer  Lily  Pond,  has 
much  more  the  aspect  of  a  quartzite,  but  with  the  lens  abundant  fresh 
secondary  grains  of  feldspar  can  be  seen  among  the  quartz  grains,  with 
many  small  garnets,  octahedra  of  magnetite,  needles  of  tremolite,  and,  in 
the  foliation  plane,  scales  of  deep-green  biotite.  In  section  the  quartz  gi'ound 
is  plainly  clastic,  the  feldspars  secondary,  inclosing  many  quartz  grains. 

3.  A  specimen  from  the  roadside  near  the  outlet  of  the  same  pond  is 
a  similar  rock,  showing  here  and  there  large  blotches  of  green  mica  scales. 
In  section  the  fine  clastic  quartz  ground  contains  many  magnetite  and 
garnet  grains,  fine  filaments  of  tremolite  with  weak  dichroism,  biotite  with 
very  strong  dichroism,  yellow  and  very  dark  olive-green,  the  latter  rarely 
changing  to  a  light-green  chlorite. 

4.  A  specimen  taken  from  a  branch  in  the  road  between  Lily  Pond 
and  the  limestone  (north  of  E.  Tylor's)  is  of  less  granular  texture  than  the 

'Geological  map  of  New  Hampshire,  17,  atlas. 


288  GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

otliers  and  less  foliated.  It  has  been  both  more  thoroughly  crushed  and 
more  completely  cemented  by  infiltrated  quartz.  In  section  it  shows  strik- 
ingly the  eifect  of  this  crushing  and  cementation.  The  quartz  ground  is 
plainly  clastic  and  like  that  of  the  other  three  specimens,  but  many  second- 
ary grains  have  grown  into  the  interstices  between  the  other  grains,  and  the 
biotite  crystals  have  rubbed  out  into  thin  scales,  twisted  and  raveled  out 
completely  and,  except  in  rare  cases  in  the  center  of  the  larger  fragments, 
changed  from  brown  to  green. 

5.  The  quartzite  east  of  the  Connecticut,  along  Perchee  Brook  and  at 
Howe's  mine,  on  the  north  line  of  Northfield  A  white,  fine-grained,  massive 
quartzite,  friable  to  compact,  containing  galena,  barite,  fluor,  pyrite,  and 
dolomite  in  the  abundant  fissures.     It  resembles  loaf  sugar. 

Under  the  microscope  this  is  made  up  of  clastic  grains  of  quartz,  among 
which  the  perfectly  fresh  and  often  idiomorphic  feldspars,  just  visible  to 
the  eye  as  shining  porphyritic  spots,  are  plainly  of  secondary  origin,  being 
limpid  at  center  and  outwardly  crowded  full  of  inclosed  quartz  grains  like 
those  outside.  These  are  sometimes  single  crystals,  sometimes  polysyn- 
thetic,  but  usually  formed  of  two  individuals  with  observed  extinctions  2°, 
5°,  and  16°  on  either  side  the  suture  in  different  individuals.  Most  of  these 
are  carlsbad  twins  of  orthoclase,  and  one  section  gave  extinction  of  21°, 
being  cut  parallel  to  M,  exactly  as  in  fig.  216  of  Rosenbusch.^  Many  grains 
of  magnetite  occur. 

6.  The  middle  outcrop  of  gneissoid  quartzite,  east  of  the  north  end  of 
the  Purple  blind  road,  Bernardston.  A  light-gray,  fine-grained  rock,  almost 
massive,  but  with  famt  parallel  structure  from  films  of  biotite.  It  has  wholly 
the  appearance  of  a  fine-grained,  gray  gneiss;  contains  quartz,  biotite,  an 
untwinned  feldspar,  muscovite,  leucoxene. 

This  shows  under  the  microscope  a  completely  granular,  clastic  mass 
of  minute,  rounded  quartz  grains.  In  this  the  rectangular  and  elongate 
sections  of  feldspar  are  plainly  of  later  growth,  inclosing  often  rounded 
quartz  grains  in  large  numbers,  especially  toward  the  outer  portion.  These 
feldspar  sections  are  plainly  visible  with  lens,  are  very  fresh  and  clearly 
idiomorphic,  and  dotted  often  with  the  contained  quartz  grains. 

The  red  biotite  is  also  notched  at  the  edges,  from  contact  with  quartz 
grains,  and  incloses  many  of  the  latter.     It  is  constantly  associated  with  the 

'Mic.  Pliys.,  1892,  under  Orthoclase,  p.  633. 


BBRNARDSTON  SERIES  OP  UPPER  DEVONIAN.  289 

leucoxone.     There  sire  many  carlsbad  twins  and  one  very  distinct  case  of 
secondary  growth  of  a,  rounded  grain  of  feldspar. 

7.  A  fine-grained,  pepper-and-salt  gneiss,  slightly  more  granitoid  and 
feldspathic  than  the  above,  from  West  Northfield,  on  section  west  from 
South  Vernon  fair  grounds,  interrupting  second  hornblendic  band.  It  con- 
tains the  same  constituents,  together  with  grains  of  plagioclase,  with'  the 
extinction  imiformly  3^-4°  on  either  side  of  the  twinning  plane.  The 
orthoclase  is  more  abundant,  larger,  wholly  xenomorphic,  and  never 
twinned;  it  cements  many  quartz  grains  together.  Leucoxene  grains  con- 
tain centers  of  ilmenite,  and  many  grains  of  black  ore  appear. 

8.  Micaceous  limestone  from  Williams  farm,  just  above  the  magnetite 
bed  at  the  opening  where  it  is  thickest.  A  black,  compact  rock,  rusting  red 
and  glistening  under  the  lens  with  fine  biotite  scales. 

Under  the  microscope  this  is  a  granular  limestone  composed  of  sub- 
angular,  equal-sided  grains  of  calcite,  many  polysynthetically  twinned. 
Biotite  is  regularly  disseminated  through  the  mass  without  being  orientated 
to  any  plane,  much  as  it  is  in  the  whetstone-schist,  to  which  rock  the  one 
under  examination  bears  a  close  resemblance  in  its  microscopical  appear- 
ance. This  biotite  is  of  so  deep  absorption  that  basal  sections  are  wholly 
opaque  except  at  the  thinnest  edge  of  the  section,  and  then  greenish-brown. 
A  single  crystal  of  hornblende  and  a  little  magnetite  and  rust  appear.  An 
arm  piece  of  a  crinoid  was  seen,  and  fragments  of  the  punctate  shell  of  a 
brachiopod,  in  which  the  centrally  expanded  center  of  the  pores  can  be 
detected. 

9.  Biotite-quartz-scHst  from  Williams  farm,  at  bluff  overlooking  brook 
at  north  end  of  limestone  and  directly  overlying  the  latter  where  excavation 
was  made  to  expose  the  fault.  A  rusty,  thin-bedded,  dark  biotite-schist 
with  much  biotite  appearing  in  the  granular  quartz  mass  and  minute,  white, 
square  needles  on  foliation  faces;  no  effervescence. 

In  section  a  granular  clastic  quartz  ground  run  through  by  veins  of 
secondary  granular  quartz  with  grains  larger  than  those  in  the  mass,  the 
whole  swarming  with  flakes  and  shreds  of  dark-brown  biotite  much  notched 
at  the  edges.  Menaccanite  surrounded  by  leucoxene,  pyrite,  and  the  prob- 
lematical needles.  These  are  long:  needles  with  longitudinal  and  transverse 
cleavage  and  longitudinal  extinction;  refraction  strong.  They  are  red- 
brown,  with  faint  pleochroism  down  the  center  and  bordered  by  a  narrow 

MON  XXIX 19 


290       GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

area  colorless  or  faintly  flesh-colored.  This  border  is  interrupted  as  if 
of  later  and  irregular  growth  on  the  sharply  defined  brown  prism,  but 
is  of  the  same  optical  orientation  as  the  latter.  It  seems  to  me  to  be 
rutile  coated  with  leucoxene. 

10.  Hornblendic  limestone;  from  upper  surface  of  the  magnetite  at 
the  ojDening  noi'th  of  the  large  quarry,  Williams  farm,  Bernardston,  and  thus 
directly  above  the  main  limestone.  An  impure  limestone,  efiFervescing 
abundantly;  dull,  mottled,  blackish-gray,  glistening  with  cleavage  faces  of 
minute  hornblende  crystals,  rusting  deep  brown. 

In  the  thin  section  a  colorless  ground  appears,  with  few  magnetite 
grains  and  many  hornblende  needles,  often  aggregated  into  compound 
crystals  of  considerable  size,  and  changing  in  small  amount  to  chlorite. 
The  hornblende  is  also  often  fasciculate  and  in  feathery  groups,  and  shows 
very  weak  pleochroism.  The  ground  consists  of  much  twinned  calcite 
grains,  with  some  quartz  and  feldspar. 

AMPHIBOLITE    ASSOCIATED    WITH    THE  LIMESTONE  IN  THE  GNEISSOID    QUAETZITE. 

11.  Amphibolite  from  South  Vernon  limestone  locality.  Immediately 
adjoining  the  limestone  on  the  north  is  a  coarse  hornblende  rock,  dark- 
gi-eeu  with  blotches  of  white,  consisting  of  a  granular  quartz-feldspar  mass, 
and  carrying  in  fissures  minute  attached  plagioclase  crystals. 

In  sections  the  large  hornblendes  are  almost  free  from  color  and  pleo- 
chroism and  are  composed  of  groups  of  needles,  sometimes  fasciculate, 
sometimes  gathered  into  large,  well-outlined  individuals,  and  entirely  unde- 
composed.  There  is  only  a  trace  of  effervescence  and  that  is  confined  to 
the  hornblende. 

12.  Amphibolite  from  South  Vernon,  south  of  road  at  E.  Gr.  Scott's, 
opposite  the  limestone.  A  greenish-gray,  fissile  rock,  resembling  a  fine- 
grained gneiss.  The  lens  shows  many  fresh  cleavage  surfaces  of  plagio- 
clase and  pale  "luster-mottled"  hornblende. 

In  section  the  large  hornblendes  inclose  many  grains  of  plagioclase, 
rutile,  and  magnetite;  they  show  marked  dichroism;  Jr  >  jc>  a;  jc  =  emer- 
ald green.  It  =  olive,  a  —  yellow;  extinction  at  21°.  Leucoxene  is  in  aggi'e- 
gates  of  grains  nearly  colorless  or  with  red-brown  centers ;  rutile  occurs  in 
square  prisms.  Fine,  large,  pale-reddish  titanite  crystals  show  ^^ositive  bisec- 
trix and  axial  figure  parallel  to  co  P  o6.  The  whole  colorless  background  is 
made  up  of  limpid  granular  plagioclase,  often  twinned  but  more  often  free 


BEENARDSTON  SERIES  OF  UPPER  DEVONIAN.  291 

from  twinning'  or  cleavage,  and  then  sliowing  the  strongest  concentric  extinc- 
tion.    Extinction  in  twinned  i)ktes,  14°-34°.     Quartz  is  scarcely  present. 

13.  Aniphibolite  from  South  Vernon,  10  rods  north  of  limestone  at  E.  Gr. 
Scott's.  A  thin-fissile,  greenish-gray  rock,  showing  with  lens  many  scales 
of  black  biotite  and  rarely  a  sharply  defined,  light-brown  prism  of  epidote. 

In  section  nearly  the  whole  field  is  covei'ed  by  a  tangled  network  of 
hornblende  blades  which  show  quite  marked  pleochroism.  The  colorless 
background  is  for  the  most  part  feldspar,  rarely  showing  twin  striation,  and, 
as  so  often  happens  in  these  hornblende  schists,  wholly  fresh  and  without 
cleavage.  Many  scalariform  or  coraloidal  grouj)s  of  leucoxene  occur, 
rarely  with  a  trace  of  black  ore  at  center,  but  each  separate  crystalline 
grain  itself  red-brown  at  center  and  colorless  superficially.  No  other  ore 
occurs. 

THE    MICA   AND    AMPHIBOLITE    SERIES. 

14.  Mica-schist  from  Bernardston,  Williams  farm,  from  the  bed  of  schist 
west  of  the  limestone.  A  dark-gray  to  black,  very  fine-grained,  even- 
bedded  slate,  with  its  glistening  surface  pitted  here  and  there  by  hemi- 
spherical hollows,  from  which  small  red  dodecahedral  garnets  have  fallen 
and  marked  by  minute  white  spots  of  shining  muscovite  scales  just  visible 
to  the  eye,  which  often  appear  in  fine  double  lines  sharply  parallel  to  each 
other  and  inclosing  a  narrow  dark  center.  They  appear  thus  like  minute 
chiastolites. 

Under  the  microscope  the  rock  shows  a  fine,  scaly,  colorless  ground, 
dusted  abundantly  with  coaly  matter,  and  with  polarized  light  showing^ 
in  abundance  minute  muscovite  scales  and  needles.  These  are  embedded 
in  a  ground  which  shows  aggregate  polarization  and  is  partly  apolar  and 
apparently  opal.  Kaolin  could  not  be  detected,  nor  "clay-slate  needles." 
The  much  fissured  garnets  have  often  a  black  boundary,  from  the  accumu- 
lation of  the  coaly  matter  expelled  from  the  space  they  occupy,  and  within 
this  a  broad  decomposition  band  of  chlorite  In  twisted  scales,  which  often 
extends  nearly  to  the  center  of  the  crystal.  They  contain  large  grains  of 
quartz  Irregularly  arranged. 

The  centers  of  the  minute  chlastollte-like  forms  mentioned  above  prove 
to  be  small,  very  Impure,  transversely  placed  blotltes  with  flat  sides  and 
raveled  ends,  having  on  each  of  their  long  sides  bands,  broader  than  them- 
selves, of  clear  muscovite  scales  placed  at  right  angles  to  the  broad  faces  of 


292  GEOLOGY  OP  OLD  HAMPSHIRE  COUNTY,  MASS. 

the  biotite  against  which  they  rest.  The  large  amount  of  coaly  matter  in 
the  centers  of  the  biotites  indicates  that  the  rock  was  more  carbonaceous 
when  the  biotite  was  formed  than  at  present.  The  biotite  incloses  garnet, 
which  was  thus  first  formed,  and  the  muscovite  has  also  folded  round  the 
garnets,  forming  small  cups  from  which  they  fall,  and  has  also,  as  above, 
arranged  itself  symmetrically  to  the  biotite,  and  is  thus  shown  to  have  been 
third  in  order  of  appearance.  Leucoxene  appears  in  yellowish-white  grains 
more  rarely  than  in  the  argillite. 

Staurolite  appears  in  some  abundance  in  stout,  shapeless  masses  nearly 
large  enough  to  be  seen  with  a  lens — red-brown  by  reflected  light,  nearly 
oi^aque  by  transmitted  light.  They  polarize  distinctly,  showing  in  the 
thinnest  places  a  mosaic  of  bright  red  and  blue,  indicating  twinning,  and 
also  traces  of  the  square  and  prismatic  sections  of  single  crystals.  Some 
crystals  giA^ng  the  proper  angles  of  staurolite  are  white  by  reflected  light, 
from  decomposition,  and  this  I  have  seen  macroscopically  in  the  schists 
around  Vernon.  Here  the  staurolite  was  removed  in  every  degree  from 
the  network  of  quartz,  until  only  a  few  brown  grains  remained,  and  at  last 
only  a  cellular  network  of  white  quartz. 

15.  Mica-schist  from  above,  and  east  of  the  quartzite,  Williams  farm. 
A  dark-gray,  fissile  muscovite-schist,  with  pimpled  surface  of  somewhat 
coarser  grain  than  the  preceding.  '  • 

The  ground  is  exactly  the  same  colorless,  scaly,  coal-dusted  mass  as  in 
the  lower  schist,  and  presents  with  polarized  light  exactly  the  same  appear- 
ance upon  a  slightly  larger  scale.  It  difi^ers  by  the  development  of  the 
transversely  placed  biotite  into  quite  large  crystals,  visible  to  the  eye  when 
the  rock  is  broken  across  the  bedding,  and  these  crystals  form  most  of  the 
pustules  which  rise  on  the  cleavage  surface  of  the  plates.  They  are  bounded 
on  the  basal  planes,  as  in  the  lower  schist,  by  a  line  of  larger  muscovite 
plates,  but  this  is  not  at  all  so  constant  as  in  the  former  case.  Scales  of 
muscovite  are  often  intercalated  in  the  biotite  with  magnetite  and  pyrite. 
The  mineral  is  a  true  biotite  (meroxene),  with  p  <Cv  and  small  divergence  of 
the  optical  axis.    Limpid  dodecadral  garnets,  magnetite,  and  pyrite  also  occur. 

Microscopic  staurolites,  single  crystals  with  qo  P,  oo  P  66,  and  0  P 
measuring  oo  P  /\  oo  P  =  115°,  go  P  /\  oo  P  66  =  112°,  are  quite  common. 
They  are  very  impure  and  nearly  opaque,  sometimes  crashed  and  the  parts 
separated.     They  are  nearly  white  by  reflected  light.     Some  slides  show 


BKRNAKDSTON  SERIES  OF  UPPER  DEVONIAN.  293 

in  almndauce  <iTJiins  of  an  ()})a({uo  black  ore,  often  partly  clian<^-ed  to  opaque 
white.  Tiiere  are  other  grains  of  an  opacpie  yellowish-wliite  material  of  the 
same  shape  and  size.     These  are  apparently  menaccanite  and  leucoxene. 

The  only  distinguishing-  cliaracteristics  to  separate  the  present  and  the 
preceding  rock  are  the  somewhat  coarser  texture  of  the  ground  in  the  former, 
the  larger  size  of  the  transverse  biotite,  and  the  somewhat  more  perfect  crys- 
talliza,tion  of  the  staurolite  and  garnet.  They  may  well  have  derived  their 
material  from  the  same  source  and  have  been  subjected  to  almost  precisely 
the  same  influences  during  metamorphism. 

The  above  descriptions  were  written  for  the  two  rocks  when  it  was 
supposed  that  the  western  schist  dijjped  below  the  limestone,  while  the  east- 
ern rested  upon  the  quartzite  above,  and  the  rocks  were  studied  in  the  hope 
of  finding  some  peculiarity  by  which  they  could  be  separately  traced.  They 
are  now  believed  to  be  part  of  the  same  stratum,  and  the  detailed  descrip- 
tions above  attest  their  lithological  identity. 

16.  Mica-schist  from  Purple's  quany.  A  dark-gray,  fissile,  garnetiferous 
muscovite-schist,  differing  from  the  upper  schist  of  the  Williams  farm  only 
in  the  gi-eater  abundance  of  garnet. 

In  a  ground  of  muscovite  scales  abundantly  strewn  with  coaly  matter 
occur  many  garnets  inclosing  scales  of  muscovite  and  bounded  by  a  decom- 
position layer  of  clilorite  in  scales  parallel  to  the  side.  The  strongly 
dichroic  biotite  plates,  much  dusted  with  coaly  matter,  are  bounded  on  0  P 
by  broad  layers  of  vertical  muscovite  scales,  which  in  one  place  inclose  a 
layer  of  fresh  orthoclase. 

17.  Massive  amphibolite  from  Bernardston,  east  of  village,  and  just  east 
of  J.  Nelson's,  the  first  house  on  the  road  turning  north  after  passing  the  Fall 
River  bridge.  Dark-gray,  jointed,  massive  rock  in  heavy  bed,  associated 
with  thin  bed  of  limestone.  Effervesces  abundantly  with  cold  hydrochloric 
acid,  especially  around  the  wisps  of  hornblende,  and  shows  then  with  the  lens 
hornblende,  biotite,  magnetite,  and  plagioclase.  Much  magnetite  removed 
from  the  powder  by  the  magnet.  The  microscope  shows  few  scattered 
wisps  of  hornblende  needles,  groups  of  grains  of  black  ore  not  associated 
with  leucoxene.     The  hornblende  shows  weak  absorption  and  pleochroism. 

18.  Massive  amphibolite  from  Bernardston,  north  of  R.  Park's,  locality  C 
cited  by  Professor  Dana  (14,  342).  (See  PL  V,  fig.  3,  for  section.)  A  mas- 
sive, black,  fine-grained,  diorite-like  rock.     The  microscope  shows  the  rock 


294       GEOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 

to  be  made  up  of  long,  interlaced,  crystalline  blades  of  hornblende  running 
in  every  direction  and  inclosing  a  great  number  of  feldspar  grains.  The 
hornblende  has  extinction  =  27°  and  is  strongly  pleochroic;  c=:  mountain 
green,  a  and  Ij  =  yellow;  one  grain  of  plagioclase,  extinction  20°  on  each 
side  of  the  twinning-  plane.  Many  sections  from  specimens  taken  from  the 
various  beds  between  this  point  and  South  Vernon  show  precisely  the  same 
structure,  but  generally  contain  grains  of  menaccanite  surrounded  by 
leucoxene. 

19.  Amphibolite  from  West  Northfield,  from  large  outcrop  rising  above 
the  terrace  sands  east  of  the  Bernardston-South  Vernon  road  at  the  point 
where  the  road  branches  off  to  the  ferry.  A  jet-black,  schistose  amphibo- 
lite, the  shining-black  hornblende  needles  being'  arranged  parallel  to  the 
foliation  plane,  but  in  every  direction  in  that  plane. 

20.  Amphibolite  from  West  Northfield,  at  first  branching-  of  the  road 
west  of  Northfield  fen-y.  A  fine-grained,  black  rock,  the  fine  black  needles 
arranged  as  in  the  last  case.  These  two  rocks  resemble  more  closely  the 
older  amphibolite  of  Northfield  Mountain  east  of  the  river  than  the  tough, 
matted,  fibrous,  massive  rock  of  the  West  Northfield  range  described  above. 
(In  the  Northfield  Mountain  rock,  however,  the  stretching  is  complete  and 
the  rock  thin-fissile,  and  the  hornblende  needles  are  all  closely  parallel  to 
one  another.  It  is  porphyritic,  has  the  usual  medium  absorption  and 
pleochroism,  x;  =  blue-green,  6f  =  olive,  a  =:  honey-yellow ;  extinction  19°.) 
Under  the  microscope  the  needles  are  grouped  in  parallel  or  almost  parallel 
bundles  to  form  large  crystals,  which  resemble  the  large  blades  of  the 
range  to  the  west,  described  above.  The  fine,  fresh  needles  are  often  well 
terminated,  the  pleochroism  strongly  marked;  c^deep  mountain  green, 
in = olive  green,  a  =  yellow.  Beautifully  complex,  large  reticulated  groups 
of  magnetite  crystals  occur,  and  with  polarized  light  the  colorless  back- 
ground breaks  up  into  a  fine-granular  plagioclase  aggregate.  The  lighter 
spots  show  the  usual  untwinned  plagioclase  mosaic.  The  grains  show  the 
usual  concentric  extinction;  the  rounded  or  angular  centers  extinguish  in 
one  position,  and  the  darkening  goes  outward  to  the  surface  with  continued 
rotation. 

21.  Limestone;  Bernardston,  northeast  of  N.  W.  Purple's  house  (now 
abandoned),  on  the  Purple  blind  road.  Layers  of  white  granular  lime- 
stone up  to  15™™  thick,  in  green,  compact  hornblende  rock. 


BEKNAKDSTON  SERIES  OF  UPPER  DEVONIAN. 


295 


Under  the  luicroscupe  grains  of  ([uartz  appear  scattered  in  a  very 
fine-<n-ained  mass  of  plumose  hornblende.  Bands  of  calcite  run  through 
this,  made  up  of  several  layers,  with  inuch  acicular  hornblende  developed 
in  it.  The  calcite  grains  are  polysynthetic.  The  hornblende  is  partly 
decomposed  into  a  bright-green,  apolar  serpentinous  mineral. 

ROCKS    AT    THE    MOUTH    OF    MILliBRS    RIVER. 

Southward  from  Northfield  the  Triassic  sandstones  border  the  river  on 
the  west  and  older  gneisses  approach  it  on  the  east,  and  the  first  exposures 


CO  f^  N  £  C   T  /  c  (J  T^ 


Fig.  20.  Sketch  map  of  rocks  near  the  mouth  of  Millers  Elver,  Erving. 

which  can  be  compared  with  the  Bernardston  series  appear  in  the  east 
bank  of  the  Connecticut  5  miles  below  Grass  Hill  and  just  above  the 
mouth  of  Millers  River  (figs.  20-22).     Here,  for  nearly  a  mile,  there  is  an 


,^^^'^,<yi^p>if^Z-:^> 


w.  ^"5 


Millers  /f/ver — 


Fig.  21.  Sketch  of  rocks  at  mouth  of  Millers  Elver,  looking  northeast  from  B  ou  map,  flg.  20.  Scale,  1:  2000.  H.  S.= 
hornblende-schists;  Q.  =  qDartzite;  GN.  =  gnei33;  GE.=granite;  M.  S.=mica.schist;  B.  GN.=hiotite-gnei8s;  Older 
Gx.— Mo.nson  Cambrian  gneiss. 

unbroken  exposure  of  rocks  of  great  interest,  which  I  have  associated  with 
the  Bernardston  series,  at  times  with  much  confidence  and  at  times  very 
doubtfully.  It  becomes,  in  fact,  a  question  how  far  the  original  sediments 
may  have  been  different  from  proximity  to  the  gneiss  instead  of  the  argil- 
lite,  and  how  far,  also,  the  immediate  presence  of  the  gneiss  during  the 
thorough  metamoi-phism  of  the  sediments  in  question  may  have  conduced 


296 


GEOLOGY  OP  OLD  HAMPSHIRE  COUNTY,  MASS. 


fer:i;u:^/?/fl>li£Wy^5 


to  a  I'esult  different  from  that  reached  where  the  underlying  mass  was 
a  nonfeldsj)athic  schist.  I  am  inchned  to  give  great  weight,  perhaps 
the  greatest  weight,  to  the  occurrence  of  the  same  succession  in  beds 
of  about  the  same  thickness — quartzite,  mica-schist,  limestone — the  latter 
changing  into  hornblende  rock,  and  to  the  tracing  of  the  beds  into  such 
close  proximity  rather  than  to  the  exact  texture  of  the  beds  themselves. 
The  following  description  will  emphasize  the  differences  in  the  latter 
regard: 

Below  the  fall  at  the  mouth  of  Millers  River,  and  on  the  north  bank 
of  the  latter,  at  a  small  crevice  in  the  cliff,  a  fault  is  plainly  seen  (fig.  21), 
the  biotite-hornblende-gneiss  which  formed  the  apron  of  the  dam  dipjjing 
10°  W.,   against    a  flinty  quartzite  which  dips   40°   W.      Following  the 

j.^  E.      outcrop  along  the  river  to 

^i^^ffoApy  its  north  end,  at  a  point 
164  feet  south  of  "The 
French  King,''^  we  find 
a  marked  promontory — 
an  island  except  at  low 
watei- — of  the  same  jas- 
pery  quartzite,  with  high 
westerly  dip,  which  is  sep- 
arated by  a  narrow  dike 
of  coarse  granite  from  the 
much  older  horizontal 
Becket  gneisses  which  crop  out  in  the  bank  of  the  river  and  continue  for 
a  long  distance  north.  The  imconformity  is  indicated  in  the  above  figure 
(fig.  22).  The  rock  at  the  promontory  is  a  very  peculiar  quartzite,  very 
thin-laminated  and  corrugated  like  the  grain  of  gnarled  oak.  Layers,  which 
sometimes  swell  to  10""",  of  black,  flinty  quartz,  wavy  and  interrupted,  alter- 
nate with  bands  of  white  to  oil-green,  compact  quartz,  producing  a  structure 
which  resembles  the  banding  of  some  eruptive  rocks  more  than  ordinary 
bedding.  The  rock  can  be  followed  south  for  600  feet  along  the  bank. 
The  ribboned  quartzite  changes  into  a  coarse  mixture  of  blue,  greasy  quartz 

'A  great  bowlder  of  Triasaic  conglomerate  which  lies  in  the  middle  of  the  river  at  the  head  of 
the  rapids,  and  derives  its  name,  according  to  tradition,  from  the  fact  that  the  bateaux  of  the  French 
and  Indians,  during  the  French  wars,  were  stopped  here  by  the  rapids,  and  one  adventurous  French- 
man pressed  on  to  this  rock  and  broke  a  bottle  of  wine  over  it,  claiming  the  country  in  the  name 
of  the  French  King. 


COA/iSE 6RAN/r£  -^l 


~  L I6HT-  G/fAy  6A/S/SS 


Fig.  22.— Section   on  east  bant  of  Connecticut  Kiver  above  montb  of 
Millers  Eiver  at  A  on  sketch  map,  fig.  20. 


BEENARDSTON  SEKIKS  OF  UPPER  DEVONIAN.  297 

and  telclsj)ar,  very  rusty  aud  carrying  pyrite  and  g'aleua,  and  rarely  niusco- 
vite  in  broad  si-ales.  Going  33  feet  along  the  strike,  one  finds  the  rock 
changing  to  a  massive,  dark  leek-green  hornstone,  which  continues  a  long 
distance,  becomes  in  places  black,  and  assumes  a  small  columnar  structure, 
and  at  last  returns  to  the  coarse  mixture  of  quartz,  flesh-colored  orthoclase, 
aud  muscovite,  the  latter  often  in  2:)lates  about  an  inch  across — the  whole 
coarsely  but  distinctly  bedded  in  laminge  1  to  2  inches  thick. 

This  is  succeeded  in  ascending  order  by  a  well-developed,  coarse 
muscovite-schist  13  feet  thick,  which  dips  beneath  a  bed  of  very  siliceous 
limestone  about  40  feet  thick,  very  rusty  externally,  in  the  interior  white 
to  flesh-colored  at  base,  but  soon  becoming  dark-green  to  black  above,  and 
very  hornblendic.  In  places  it  is  a  pure  amphibolite,  but  it  is  generally 
mottled  with  white  calcite.  It  is  cut  by  two  dikes,  3  to  7  feet  thick,  of 
coarse  granite.  Then  begins  a  great  bed  which  seems  to  rest  uj)on  the 
hornblende-calcite  rock,  but  the  exposure  leaves  this  indistinct.  This  bed 
begins  at  base  as  a  greenish,  apparently  calciferous  quartzlte  (it  rusts 
deeply),  and  makes  the  mass  which  projects  into  the  Connecticut  at  a  point 
just  north  of  the  mouth  of  Millers  River.  At  base  some  parts  are  conglom- 
eratic, quartz  pebbles  one-half  to  1  inch  long  occurring.  This  rusty  layer 
is  about  20  feet  thick.  Then  a  thin  layer  of  amphibolite,  like  the  other, 
caps  the  quartzite  for  a  short  distance  (72  feet)  along  the  water's  edge,  and 
the  latter  rock,  the  quartzite,  runs  on  in  great  undulations  for  656  feet 
toward  Millers  River,  its  average  strike  agreeing  closely  with  the  course  of 
the  Connecticut  at  that  point  (S.  60°  W.)  and  its  dip  being  42°  W.  The 
high,  bare  cliff's  give  almost  unbroken  exposures  between  the  two  exposures 
of  the  fault  at  the  extremities  of  the  section,  and  leave  the  stratigraphy 
uncertain  at  only  one  point.  The  upper  quartzite  is  thin-fissile  in  its  upper 
layers,  bluish  at  times,  and  repeating  all  the  flinty  varieties  seen  at  "The 
French  King"  (16  feet).  At  the  great  point  just  north  of  the  mouth  of 
Millers  River,  where  the  shore-line  swings  round  to  the  east  as  one  passes 
up  the  bank  of  the  latter  stream,  this  grades  below  into  a  perfect  feldspathic 
gneiss  of  medium  grain,  with  a  little  greenish  mica  (20  feet),  which  passes 
below  into  coarse  granitic  gneiss  or  a  gneiss  breaking  in  laminae  nearly  an 
inch  thick  but  composed  of  the  coarse  orthoclase  and  large  muscovite 
scales  of  a  common  coarse  granite.  The  muscovite  scales  are  often  an 
inch  broad,  and  are  generally  in  the  plane  of  foliation  (30  feet). 


298  GEOLOGY  OF  OLD  HAMPSHIEB  OOUFTY,  MASS 


This  stratum  is  followed  below,  just  at  the  junction  of  the  rivers,  by 
a  heavy  bed  of  a  very  coarse,  very  micaceous  muscovite  -  schist.  This 
mica-schist  incloses  a  great  number  of  lenses  of  coarse  granite,  its  laminae 
separating  to  inclose  them,  and  the  strike  of  the  rocks  continues  closely 
parallel  to  the  course  of  the  Connecticut.  This  stratum  passes  beneath 
the  water  at  the  place  of  junction  of  the  two  rivers,  and  the  granite 
lenses  rise  in  twelve  small  islands  which  stretch  across  the  mouth  of 
Millers  River  (105  feet). 

The  mica-schist  changes  suddenly  below  into  a  dark,  much-jointed  and 
yet  fissile  biotite-gneiss.  The  biotite  is  bronze-colored,  but  green  superfi- 
cially. This  is  followed  finally  by  the  basal  quartzite,  containing  at  first 
bands  of  coarsely  feldspathic  quartzite  with  scattered  red  garnets  like  those 
common  in  granite,  and  broad  flakes  of  muscovite,  and  with  quite  large  gran- 
ite lenses.  Below  it  is  for  the  most  part  a  green  to  flesh-colored,  compact 
quartzite  with  feldspathic  and  biotitic  layers,  and  resembling  closely  that 
at  the  north  end  of  the  exposure  at  "The  French  King,"  and  faulted,  as 
already  detailed,  against  the  older  gneiss  just  below  the  bridge  over  Millers 
River.     (See  fig.  21,  p.  295.) 

The  order  from  the  fault  upwai'd  is,  thus,  at  both  ends:  (1)  quartzite, 
(2)  mica-schist,  (3)  amphibolite  and  limestone;  and  it  is  doubtful  whether 
the  order  continues  upward,  (4)  rusty  quartzite,  (5)  amphibolite,  or 
whether  the  two  upper  are  repetitions  of  the  lower  members  of  the  series. 

Crossing  Millers  River,  the  fault  line  runs  through  the  high  Mine  Hill 
west  of  the  village  of  Millers  Falls,  and,  especially  the  band  of  schist  and 
gneiss  impregnated  with  granitic  material,  makes  the  crest  of  the  hill.  This 
band  is  greatly  brecciated  and  its  fissures  are  filled  with  magnetite,  which 
has  suggested  the  name,  while  on  the  western  slope  a  greenish  compact 
quartzite  or  hornstone  caps  the  feldspathic  beds. 

Southward  across  the  Montague  plain  all  the  outcrops  are  to  the  east 
of  the  line  of  junction  of  the  two  formations,  and  thus  lie  in  the  older  gneiss, 
until,  on  the  southern  border  of  the  great  sand  plain  and  just  northeast  of 
the  village  of  Montague,  there  occurs  a  great  mass  of  the  same  gray  to 
pale-green,  greatly-jointed  and  brecciated  quartzite,  quite  massive  and 
hornstone-like  in  texture.  A  few  rods  to  the  east,  across  the  railroad,  the 
older  gneiss  rises  above  the  sands,  dipping  beneath  the  quartzite.  South 
and  west  everything  is  covered  by  the  Triassic  sandstones,  but  on  the  north 


IJEKNAKDSTON  SERIES  OF  UPPER  DEVONIAN.  299 

faco  ot"  the  hill  west  ot"  Montague  a  coarse  gneiss  showing  traces  of  con- 
glomerate structure  rises  out  of  these  sandstones  and  is  most  nearly  allied 
to  the  coarser  rocks  at  the  mouth  of  Millers  River,  with  which  I  have  asso- 
ciated it  on  the  map.     (See  p.  362.) 

Along  the  fault  line  northward  from  the  mouth  of  Millers  River  across 
Nortlifield,  the  older  gneisses  rise  from  beneath  the  sands  in  many  places 
up  to,  but  not  beyond,  the  line  of  the  fault,  while  the  few  outcrops  of  the 
Bernardston  series  approach  the  same  line  on  the  west  until,  ojjposite 
Northfield  village,  in  L.  A.  Moody's  lane,  the  Devonian  quai'tzite,  identical 
with  that  west  of  the  river  on  the  Williams  farm,  here  greatly  brecciated 
and  its  fissures  filled  with  hematite,  approaches  very  near  to  the  older  rocks, 
and  the  same  thing  is  true  northward  along  the  road  which  skirts  the  moun- 
tain to  and  beyond  the  State  line,  where  the  fault  enters  the  older  rocks,  as 
shown  on  the  map,  PI.  XXXIV. 

The  quartzite,  greatly  brecciated,  and  veined  with  hematite,  can  be 
traced  in  several  places  into  near  proximity  to  the  older  series.  It  is  a  fine- 
grained rock  which  shows  no  signs  of  derivation  from  the  varying  members 
of  the  older  series  against  which  it  successively  rests.  It  fails  to  conform  to 
them  in  dip  and  strike,  and  these  facts,  combined  with  its  thorough  breccia- 
tion  along  this  whole  line,  make  it  probable  that  the  Bernardston  series  is 
bounded  on  the  east  by  the  extended  fault  which  has  been  traced  north  and 
south  from  Millers  River. 


CHAPTER    X. 

THE   AMPHIBOLITES    DESCRIBED   IN    THE    PRECEDING 

CHAPTERS. 

A]SrALXSES   AND   SECTIOKS. 

I  have  in  the  preceding  chapters  described  a  great  variety  of  amphibo- 
Utes,  and  have  assigned  most  of  them  with  more  or  less  confidence  to  the 
list  of  altered  sedimentary  rocks.  Forms  which  are  associated  with  basic 
eruptive  rocks  or  retain  any  traces  of  the  structure  of  those  rocks  I  have 
classed  with  eruptive  rocks.  Varieties  which  form  selvages  to  limestone 
beds,  or  are  in  every  way  closely  associated  with  limestones  and  inter- 
bedded  with  the  schists  in  which  they  occur,  I  have  considered  to  be 
derivatives  from  impin-e  limestones.  Without  recapitulation,  I  may  call 
attention  to  the  discussion  of  the  amphibolites  associated  with  Algonkian 
limestones,  on  pages  29—30,  and  of  the  origin  of  the  Chester  amphibolite, 
on  pages  147-155,  and  to  the  description  of  the. amphibolites  of  the  Hawley 
series,  on  pages  166-169,  and  of  those  more  certainly  derived  from  lime- 
stones in  the  Conway  schist,  on  pages  189-196,  and  in  the  Bernardston 
series,  on  pages  275-282,  290-294,  297.  I  bring  together  here  for  com- 
parison all  the  analyses  of  amphibolites  from  the  region,  and  a  series  of 
sections  commencing  with  forms  which  are  certainly  sedimentary  and  end- 
ing with  those  concerning  whose  origin  there  Avill  be  difference  of  opinion. 
A  curious  porphyritic  structure  which  is  common  in  the  amphibolites  is  also 
briefly  discussed. 

I  have  described  many  beds  of  amphibolite  that  may,  with  more  or 
less  certainty,  be  derived  from  limestone.  I  have  perhaps  given  too  much 
weight  to  this  mode  of  derivation,  and  may  have  included  beds  of  igneous 
origin.  It  is  very  striking  how  small  the  chemical  variation  is  in  rocks 
differing  widely  in  age,  habit,  and  probable  origin,  and  the  close  agreement 
of  all  these  analyses  with  that  of  an  average  disbase  will  not  escape  atten- 

300 


PLATE  Y. 


301 


PLATE    V. 

SECTIONS  OP  AMPHIBOLITES  DERIVED  PROM  LIMESTONES. 

Silurian  and  Devonian  age.  Drawn  with  lower  niools  to  show  the  pleochroism  of  the  hornblende. 
The  upper  nicol  is  used  to  bring  out  the  outlines  of  the  colorless  mosaic.  The  plane  of  polari- 
zation is  parallel  to  the  long  side  of  the  plate.  The  hornblende  crystals  are  generally  full  of 
colorless  grains  like  those  of  the  ground.     All  show  remnants  of  calcite.     x  20. 

Pig.  1.— Calcareous  garnet-amphibolite.  Conway  schist,  Plainfield.  From  the  base  of  the  large 
"anvil,"  figured  in  PL  XXXIII  and  described  on  page  191,  and  formed  by  the  metamorphism  of 
the  impure  limestone  which  still  makes  the  shaft  of  the  anvil.  The  rock  has  the  aspect  of  a 
coarse  hornblende-schist,  but  effervesces  with  acid.  The  coarser-grained  portion  of  the  color- 
less mosaic  is  clastic,  identical  with  that  of  the  adjacent  mica-schist,  and  the  garnets  have  the 
same  symmetrical  arrangement  of  the  coaly  impurities.  The  finer  part  of  the  colorless  ground 
is  plagioclase.  One  large  grain  is  marked  by  triclinic  striation  and  most  of  it  is  crushed.  The 
biaxial  character  of  many  grains  could  be  determined.  Extinction  37°,  indicating  anorthite. 
The  ragged  hornblende  plates  inclose  many  colorless  grains,  generally  quartz  or  calcite,  but 
sometimes  small  colorless  zircons  with  deep  halos  of  darker  color.  The  dull  portions,  heavily 
dusted  with  carbon  grains,  are  remnants  of  corroded  calcite.  Swarms  of  leucoxene  grains 
surround  ilmenite.     (See  Analysis  I,  p.  303.) 

Pig.  2.— Amphibolite.  Whately.  Prom  bridge  west  of  the  Whately  Hotel.  A  black,  massive 
amphibolite;  forming  portion  of  limestone  bed  in  Conway  schist  and  folded  into  argillite. 
The  long  hornblende  blades  are  often  centrally  brown,  with  colorless  ends,  and  loaded  with 
transverse  black  bands  which  send  out  comb-like  teeth  parallel  to  the  vertical  axis.  There  is 
some  biotite.  Red  rutile  surrounds  black  ore,  and  small  colorless  zircons  (?)  appear,  surrounded 
by  dark  halos.  There  is  a  mosaic  of  feldspar  without  twinning  and  generally  without  cleavage. 
(See  pp.  192,  196.) 

Fig.  3.— Amphibolite.  Bernardston,  near  R.  Park's.  Prom  the  Devonian  Bernardston  series.  A 
black,  massive  rock,  made  of  broad,  stout,  interlaced  blades  of  hornblende.  These  blades 
grade  into  radiate  tufts  of  hornblende  needles.  The  hornblende  crystals  inclose  many  color- 
less grains,  often  of  branching  and  irregular  forms,  resembling  the  grains  of  titanite  which 
surround  some  of  the  black  ore  masses  in  the  slide.  Some  of  the  grains  of  the  colorless  mosaic 
are  twinned  and  have  generally  the  small  extinction  angle  of  albite.  Others  show  secondary 
growths  around  rounded  centers.  One  fine  fibrous  and  punctate  fragment  seems  to  be  organic, 
resembling  a  brachiopod  shell.  It  is  too  small  to  show  in  the  drawing.  (See  Analysis  VII, 
p.  303,  and  comparative  discussion,  p.  275.) 

Fig.  4.— Garnet-graphite-amphibolite.  Bowlder  from  Leverett,  but  coming  with  great  probability 
from  one  of  the  coarser  Bernardston  beds  or  from  the  great  Guilford  bed  in  the  Conway 
schist,  figured  on  PI.  VI  (fig.  2).  A  complete  block  of  massive  amphibolite.  The  stout 
interlacing  blades  of  hornblende  contain  in  their  meshes  little  granular  mosaic,  which 
decomposes  readily  and  gives  a  beautiful  surface.  The  fresh  surface  effervesces.  A  few  gar- 
nets appear.  The  striking  peculiarity,  indicating  the  derivation  of  the  rock  from  a  graphitic 
limestone,  is  that  the  surface  of  very  many  of  the  hornblende  crystals  show  shining  scales  of 
graphite,  which  only  rarely  appear  in  the  photograph,  x  h 
302 


us  GEOLOGICAL    SURVfY 


MONOGRAPH  XXtA.    PL.V. 


X20 


X20 


X20 


>.ii 


CHARLOTTE   F.  EMERSO  N, FECIT. 


""SadwiT^lIieEaEiIlfliniTCo' 


AM  PHI  BO  LIT  ES 


ANALYSES  OP  TYPES  OF  AMPHIBOLITE. 


303 


tiou.  No.  IX  is,  however,  certainly,  and  Nos.  I,  IV,  and  V  are  almost 
certainly,  derived  from  limestone.  There  is  therefore  no  reason  from  the 
chemical  side  why  they  should  not  all  be  so  derived. 

Analyses  of  the  amphiholites  described  in  the  preceding  chapters. 

[Analyst,  L.  G.  Eakius.] 


'- 

I. 

II. 

III. 

IV. 

V. 

VI. 

• 

VII. 

VIII. 

IX. 

SiO.. 

51. 38 

1.07 

18.01 

45.48 

.77 

19.43 

trace 

.13 

6.58 

trace 

.01 

10.66 

11.08 

.11 

2.28 

3.17 

.14 

.20 

51.56 

1.97 

14.82 

49.86 

1.58 

15.50 

49.16 

1.03 

16.43 

trace 

3.92 

7.19 

.23 

.02 

9.21 

8.19 

.41 

3.70 

.45 

.16 

48.53 

.51 

16. 35 

51.72 

1.39 

16.51 

47.56 
1.24 

16.13 

trace 

1.80 

9.39 

.08 

trace 
6.67 
9.21 
1.58 
2.52 
3.51 
.21 

55.64 

.50 

16.27 

TiO. 

AI2O3 

Fe-Os 

FeO 

3.30 
8.53 

.19 

trace 

6.27 

5.08 

.18 
5.34 

.56 

.18 

4.30 

7.21 

trace 

trace 

7.09 

7.36 

.17 

4.21 

1.47 

.09 

2.99 
8.01 

.07 

trace 

8.89 

7.79 

.72 
3.26 
1.51 

.11 

2.03 
10.52 

.17 

trace 

9.83 

9.71 

.32 
1.36 

.79 

.07 

1.72 

9.56 

trace 

trace 

8.89 

6.58 

.34 

2.74 

.51 

.23 

1.22 
7.20 

.28 

MnO  

CaO 

9.23 

5.58 

.19 

.91 

3.11 

.23 

Mo-0                 

KcO 

Na.O          

H,0 

PcOb 

100.  09 

100. 04 

100. 25 

100.  29 

100. 10 

100. 19 

100. 19 

99.90 

100.  36 

I.  Heath;  W.  M.  Sanford's.     Porpliyritic  amphibolite  in  Goshen  schist. 
II.  New  Salem.     Amphibolite  associated  with  steatite. 

III.  Leverett;  gothic  house  east  of  village.     Massive,  coarse,  altered  diabase. 

IV.  Whitmores  Ferry ;  Sunderland.    Thin,  shaly,  aphanitic  amphibolite  of  Conway  age  project- 

ing through  Triassic  sandstone. 
V.  Guilford,  Vermont ;  shining-black,  flaggy  amphibolite;  long  bed  in  Conway  schist. 
VI.  Worthington;  in  Hawley  schist ;  nearly  pare,  matted,  black  hornblende  needles. 
VII.  Bernardston;  E.Park's.     Black,  heavy,  massive  hornblende  rock.     Devonian. 
VIII.  South  Leverett.     Ligniform,  deep-green  amphibolite. 
IX.  Goshen ;  base  of  the  "anvil"  formed  by  solution  of  the  block  of  impure  limestone,  and  thus 
certainly  derived  from  limestone  of  Conway  age.     (See  p.  191.) 

In  the  accompanying  plates  (Pis.  V,  VI)  I  have  brought  together 
types  of  all  the  amphibolites  described  in  the  preceding  chapters  for  com- 
parison with  the  table  of  analyses  given  above.  The  sections  on  PL  V 
are  certainly  derived  from  limestone.  The  first  two  sections  on  PL  VI 
have  probably  the  same  origin.  The  third  section,  from  the  Hawley  schist, 
and  the  fourth,  which  is  from  a  bed  adjacent  to  the  great  Chester  amphibo- 
lite, are  of  uncertain  origin. 


304  GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

POEPHYRITIC   CHARACTER   OF  THE  AMPHIBOLITES. 

The  hornblendic  bands  of  tlie  Bernardston  series  are  often  pseudo-por- 
phyritic,  especially  west  of  the  Mount  Hermon  School.  This  structure  is 
widel3^  distributed  in  older  amphibolites  from  the  Hawley  to  the  Conway 
series,  both  inclusive,  especially  in  the  Gruilford  and  Heath  amphibolites 
and  the  large  upper  band  of  the  Hawley  schist  (see  p.  166).  It  reappears 
again  in  the  Conway  schists  in  Grranville,  and  is  seen  in  the  most  striking 
form  in  South  Monson  (see  p.  249).  The  dark  surface  of  the  rock  is  inter- 
rupted by  white  spots  2-10'"™  in  length,  more  or  less  angular  and  of  some- 
what uniform  size.  A  quite  close  inspection  will  often  leave  the  impression 
that  they  are  formed  simply  by  the  expulsion  of  the  hornblende  needles 
from  the  area,  and  are  a  portion  of  the  granular  base  of  the  rock,  but  a 
bright  light  Avill  show  at  times  the  flash  of  a  common  cleavage  over  the 
whole  or  half  of  the  surface. 

With  polarized  light  tlie  same  effect  is  produced.  A  simple  mosaic  of 
feldspar  grains  appears,  but  by  using  a  very  low  power  it  can  generally 
be  seen  that  the  groundmass  is  held  together  by  a  single  large  feldspar 
growth,  so  crowded  with  foreign  bodies  that  it  can  hardly  be  separated. 

I  compare  these  feldspar  growths  to  those  described  on  page  287  in 
the  Bernardston  quartzites,  or  the  small  porphyritic  albite  crystals  in  the 
Hoosac  schists,  and  consider  them  the  earlier  generation  (as  compared  with 
the  hornblende  needles)  in  their  present  position.  They  often  include 
minerals  of  early  growth,  as  biotite  and  dolomite  (which  are  now  wanting 
in  other  parts  of  the  rock),  as  well  as  the  common  groundmass,  and  have 
by  their  early  presence  prevented  the  iron-bearing  mineral  from  occupying 
their  place.  They  are  now  often  saussuritic,  made  up  wholly  or  largely  of 
highly  refringent  epidote,  or  zoisite  grains,  very  possibly  as  the  result  of  a 
paramorphic  change  at  the  time  of  the  development  of  the  hornblende. 

The  whole  process  is  one  more  intelligible  as  occurring  in  a  calcareous 
red  sandstone  than  in  a  metamorphosed  diabase,  and  it  is  very  common  in 
the  amphibolites,  which  occur  in  thin,  extended,  conformable  sheets,  grade 
more  or  less  into  limestone,  and  show  no  tendency  to  form  sei"pentine  and 
steat^'te,  and  it  is  wanting  in  the  gabbro-like  beds  and  in  the  great  Chester 
amphibolite,  which- is  associated  with  olivine  and  enstatite  rocks,  serpentine, 
steatite,  and  emery,  and  which  may  thus  be  derived,  at  least  partly,  from 
beds  of  distinctly  eruptive  origin. 


PLATE   VI. 


305 


MON  XXIX 20 


PLATE  VI. 

SECTIONS   OF  AMPHIBOLITES  PROBABLY  DERIVED  FROM   IMPURE  LIMESTONES. 

Silurian.  Drawn  with  lower  nicols  to  show  pleochroism.  The  upper  nicol  is  used  to  bring  out 
the  outlines  of  the  grains  in  the  colorless  mosaic.  The  plane  of  polarization  is  parallel  to  the 
long  side  of  the  plate.  The  hornblende  grains  are  generally  free  from  grains  of  the  plagio- 
clase.     X  20. 

■piG.  1. — Magnetite-amphibolite.  Conway  schist,  Whately.  From  the  north  end  of  the  large  band 
near  house  of  Mrs.  M.  Taylor.  A  black,  slaty  rock,  easily  mistaken  for  a  black  shale.  A  rock 
of  very  fine  and  even  grain.  Many  of  the  ore  grains  are  surrounded  by  small  groups  of  titanite 
grains,  many  grains  of  which  are  scattered  evenly  in  the  whole  field.  A  narrow  vein  filled  with 
large  and  long  plagioclase  grains,  like  the  ground,  crosses  the  slide.  (See  Analysis  IV,  p.  303, 
and  for  description  p.  194.) 

Fig.  2. — Rutile-epidote-amphibolite.  South  line  of  Guilford,  Vermont.  A  shining-black  schist, 
slightly  larger  needles,  black  and  lustrous,  appearing  among  the  others.  A  limpid  granular 
mosaic,  in  small  quantity,  no  multiple  twinning,  rarely  cleavage,  one  probable  determination 
of  albite.  Hornblende  ragged-bordered,  but  without  inclosures,  with  strong  pleochroism  and 
cleavage.  Much  deep-red  brown  rutile  clustering  around  black  ore  grains.  Considerable  pale- 
yellow  epidote.     (See  Analysis  V,  p.  303,  and  for  description  p.  195.) 

Fig.  3. — ^Epidote-amphibolite.  Hawley  series.  Heath,  near  E.  Gleason's.  With  large  porphyritic 
hornblendes  and  feldspars.  A  fine-grained,  limpid  feldspar  mosaic,  thick  set  with  minute  but 
quite  well-formed  hornblende  and  rounded  epidote  grains.  The  large  hornblendes  show 
remarkably  strong  pleochroism  when  viewed  with  a  lens  without  the  intervention  of  nicols, 
and  twinning,  both  of  which  properties  are  indicated  in  the  figure.  They  are  centrally 
filled  with  minute  foreign  bodies.  The  feldspar  crystals  are  centrally  filled  with  highly 
refringent,  slightly  yellow  grains  of  epidote,  and  the  same  are  scattered  through  the  ground. 
The  distinctly  bounded  feldspar  crystals  are  mostly  broken  into  a  mosaic.  One  shows  trace  of 
carlsbad  twinning,  but  no  cleavage  or  multiple  twinning  can  be  seen.  The  abundant  grains 
of  magnetite  show  no  trace  of  change.    The  red  grains  are  much  rusted  ankerite.    (See  p.  166.) 

j'lQ.  4. — Amphibolite.  Chester.  From  the  cut  nearest  to  the  station.  A  black  rock  banded  with 
white  layers,  which  are  thin  and  interrupted,  the  mass  of  the  rock  made  of  shining,  jet-black 
needles  just  visible  to  the  eye.  Under  the  microscope  the  rook  is  very  fresh,  the  hornblendes 
are  in  long,  ragged-ended,  parallel  blades  with  few  inclusions  and  strong  pleochroism.  Extinc- 
tion 21°.  The  coarse,  limpid  ground  mosaic  is  made  up  of  quartz  and  albite  grains,  polarizing 
brilliantly  and  hardly  distinguishable  from  one  another,  except  that  the  quartz  gives  the  black 
cross  and  the  feldspar  is  positive  and  biaxial.  This  mosaic  resembles  exactly  that  of  the 
adjacent  sericite-schist.  There  is  no  trace  of  any  other  mineral  except  these  three.  (See 
pp.  97,  160.) 
306 


U  S  GEOLOSICAL    SURVEY 


MONOGRAPH  XXIX.    PL.  VI. 


aackoK  ftWilhehna  titho.RPfi  Co 


AMPHIBOLITES 


_  CHAPTER     XI. 

THE  ERUPTIVE  ROCKS. 

INTRODUCTION. 

The  species  of  igneous  rocks  occurring  within  the  area  of  the  crystal- 
line schists  are: 

1.  Granite,  in  the  strict  sense,  or  biotite-muscovite-granite,  the  most 
widely  distributed. 

2.  Granitite,  or  biotite-granite,  generally  porphyritic. 

3.  Pegmatite,  or  muscovite-granite. 

4.  Albitic  granite  in  secondary  veins  in  the  pegmatite,  remarkable  for 
their  content  of  rare  elements. 

5.  Aplite. 

6.  Quartz-gabbro. 

7.  Tonalite,  or  quartz-diorite,  wholly  or  in  part  derived  from  No.  7,  and 
with  it  forming  the  syenite  of  President  Hitchcock. 

8.  Diorite. 

9.  Diabase. 

10.  Cortlandite. 

Within  a  square  twenty -five  miles  on  a  side,  with  Northampton  at  its 
center  and  its  eastern  line  along  the  foothills  on  the  east  side  of  tlie  broad 
Connecticut  Valley,  in  Belchertown  and  Pelham,  the  country  consists  for 
the  most  part  of  large  areas  of  granitic  rocks  of  the  above  types.  Where 
schists  cross  the  region  they  are  contorted  and  granite-impregnated,  and  rest 
upon  the  granite  in  separate  sheets,  often  of  small  size,  or  narrow  bands, 
and  all,  down  to  the  smaller  fragments,  retain  their  dip  and  strike,  even 
when  surrounded  on  all  sides  by  the  massive  rock. 

A  large  portion  of  the  area  outlined  above  lies  beneath  the  sands  and 
sandstones  of  the  Connecticut  Valley,  and  the  line  of  Triassic   eruptions 

307 


308  GEOLOGY  OP  OLD  HAMPSHIKB  COUNTY,  MASS. 

bisects  it  from  north  to  south,  so  that  the  great  depression  of  the  valley 
seems  to  be  connected  with  these  ancient  granitic  intrusions. 

Outside  the  area  defined  above  granite  dikes  are  few  and  small,  the  only 
large  ones  being  the  Middlefield  and  Coys  Hill  dikes.  Topographically, 
and  in  the  interest  of  cartographic  work,  they  may  be  divided  into  four 
groups:  (a)  the  great  stocks  and  dikes  of  muscovite-granite,  with  their 
accompanying  swarms  of  smaller  dikes,  the  whole  surrounding  the  groups 
b  and  c  below ;  (If)  the  extended  central  areas  of  quartz-gabbro  and  tonalite 
(syenite  of  President  Hitchcock),  which  are  without  accompanying  dikes; 
(c)  the  biotite-muscovite-granite,  which  occupies  great  areas  topographically 
as  well  as  lithologically  intermediate  between  the  other  two,  and  is  with  dif- 
ficulty separated  from  the  former  (a)  because  it  is  itself  cut  by  an  enormous 
number  of  veins  of  muscovite-granite,  or  pegmatite,  not  distinguishable 
from  that  of  the  group  a  itself,  so  that  it  could  often  as  well  be  assigned  to 
the  one  as  to  the  other  on  the  map;  (d)  the  porphyritic  biotite-granites, 
which  are  widely  separated  from  the  above  group. 

At  the  two  opposite  corners  of  the  granitic  region  are  two  great  squar- 
ish masses  of  quartz-hornblende  rocks  (tonalite),  which  send  out  no  dikes, 
and  which  have  produced  a  much  more  intense  contact  metamorphism  than 
the  mica-granites. 

The  Hatfield  tonalite  area  is  immediately  succeeded  on  the  west  by  a 
fine-grained  biotite-granite  almost  like  the  Monson  gneiss,  but  which  from 
the  beginning  carries  a  small,  constant  quantity  of  muscovite.  To  the  west 
it  soon  begins  to  be  cut  by  pegmatite  dikes,  and  at  the  Mill  River  in 
Leeds,  a  mile  west,  their  number  is  already  considerable.  In  the  next  mile 
west  the  belt  of  granite  which  stretches  from  Loudville  to  "Williamsburg 
has,  as  it  were,  a  substratum  of  the  fine-grained  biotite-  (or  two-mica-) 
granite,  but  so  cut  up  by  successive  generations  of  the  coarser  muscovite- 
granite  that  it  almost  disappears  beside  the  latter. 

Then  still  farther  west  and  south,  and  on  much  higher  ground,  the 
great  rounded  granite  stocks,  which  stretch  from  Montgomery  to  Conway 
and  rise  to  form  some  of  the  highest  hills  on  our  western  horizon — 
Pomeroy  Mountain,  in  West  Hampton,  and  Moores  Hill,  in  Goshen — are 
desolate  regions  of  a  coarse  muscovite-granite,  rarely  slashed  by  great  blades 
of  biotite,  in  which  one  finds  here  and  there  large  areas  or,  as  on  the  top  of . 
Moores  Hill,  an  isolated  block  of  the  fine-grained  biotite-granite. 


o 


THE  ERUPTIVE  ROCKS.  309 

Up  to  this  point  the  description  covers  an  area  of  unbroken  granitic 
rocks  of  various  types,  superficially  separated  by  shallow  bridges  of  schist. 
Like  the  roots  of  a  great  tree  inverted,  there  radiate  from  this  central  mass 
numberless  dikes  of  every  size,  the  connection  being  proved  in  many  cases 
and  probable  in  all.  These  dikes  are  of  two  kinds,  the  fine  and  uniform 
grained  biotite-  (or  two-mica-)  g-ranites  or  granitite,  and  the  coarse  to  very 
coarse  muscovite-granite  veins — pegmatite.  The  former  are  generally,  the 
latter  sometijnes,  interbedded  in  the  schists  for  long  distances.  Toward  the 
periphery  of  the  area  the  pegmatite  dikes  carry  secondary  veins  of  albitic 
granite  with  many  rare  minerals.  Within  the  area  cut  by  the  dikes  and 
suiTOunding  it  in  a  broad  halo  the  country  rock  is  filled  with  quartz  veins 
and  pegmatite  lenses  of  every  size,  derived,  I  doubt  not,  from  the  granite. 

On  the  eastern  side  of  the  river  there  stretches  north  from  the  Bel- 
chertown  tonalite  ("syenite")  area  a  region  where  the  schists  are  so  crowded 
with  pegmatite  veins  that  they  (the  schists)  sink  into  unimportance.  This 
continues  across  Amherst,  and  in  Leverett  is  followed  by  a  large  area  of 
almost  unbroken  granite. 

The  discovery  and  description  of  the  peculiar  type  of  eruptive  masses 
to  which  the  name  "  laccolites  " '  has  been  given  by  Gilbert — great  mushroom- 
like bodies  of  lava  thrust  up  into  the  bedded  rock  to  a  certain  level  and  then, 
expanding  into  a  cake-like  mass  between  the  beds,  pushing  up  the  superin- 
cumbent strata  into  a  low  dome,  but  not  reaching  the  surface — suggested  to 
E.  Suess^  the  name  "batholites"  for  the  similar  but  more  extensive  masses  of 
granite  which  occupy  a  position  in  the  crystalline  schists  analogous  to  that 
of  the  laccolites  in  the  newer  rocks.  It  is  in  this  connection  that  the  obser- 
vation of  Hitchcock  is  interesting,  that  the  great  masses  of  granite  seem  to 
be  set  free  by  the  denudation  of  the  schists  above  them,  and  the  furth'er 
observation — ^which  I  have  had  occasion  to  make  repeatedly — that  where 
the  schists  are  so  cut  up  by  the  interlacing  granite  dikes  that  the  latter 
make  up  far  the  greater  portion  of  the  surface,  and  even  where  long  isolated 
sheets  stand  vertical  or  nearly  so  in  the  great  granite  masses,  the  prevalent 
strike  and  dip  of  the  suiTounding  schists  are  strictly  maintained,  indicating 

'  G.  K.  Gilbert,  Kept.  Geol.  Henry  Mountains.  A.  C.  Peale,  On  a  peculiar  type  of  eruptive 
mountains  in  Colorado:  Bull.  U.  S.  Geol.  and  Geog.  Surv.  Terr.,  No.  3,  p.  551.  F.  M.  Endlich,  Erup- 
tive rocks  of  Colorado:  Tenth  Ann.  Kept.  U.  S.  Geol.  and  Geog.  Surv.  Terr.,  p.  199. 

*  E.  Suess,  Das  Antlitz  der  Erde,  p.  219. 


310       GEOLOGY  OP  OLD  HAMPSHIEE  COUNTY,  MASS. 

that  they  are  downward  projections  of  the  roof  of  the  bathoUte,  which  has 
been  removed  just  to  their  average  plane  of  junction.  Such  a  great  batho- 
hte  is  well  seen  in  Mount  Tekoa,  in  Montgomery.  To  one  standing  on  the 
high  ground  on  the  west  line  of  Westfield  and  looking  north  the  contrast  of 
the  white  granite  and  the  black  schist  is  strongly  marked.  On  the  right  the 
great  dome  of  granite  makes  the  sky-line.  To  the  left  its  curved  surface 
passes  down  beneath  the  mass  of  the  schists  of  Mount  Tekoa.  The  latter 
at  first  mantle  up  over  the  dome  conformably,  and  higher  up  end  very 
obliquely  on  the  contact  plane,  and  are  greatly  cori'ugated  and  cut  by 
many  large  dikes  sent  off  from  the  main  mass. 

Again,  these  schists  and  their  limestones,  entangled  in  the  granite, 
have  been  subjected  to  the  same  kind  and  degree  of  contact  metamorphism 
as  the  broad  band  surrounding  them.  The  schists  became  feldspathic  and 
the  limestones  coarsely  crystalline,  as  described  under  the  head  of  the  Con- 
way mica-schist,  page  197,  while  the  hornblende-schists  became  pyroxenic 
(as  described  on  p.  243)  or  feldspathic  with  or  without  the  development  of 
pyroxene.  I  look  upon  the  larger  masses  as  great  granitic  reservoirs' 
which  have  partly  forced  and  partly  melted  then-  way  up  through  the  schists 
to  the  place  where  they  are  found,  absorbing  much  of  the  material  of  the 
latter  in  their  progress  and  sending  upward  and  outward  a  complex  radi- 
ating network  of  dikes. 

I  consider  the  two  great  stocks  of  "tonalite"  described  below  to  be 
partially  denuded  domes  of  these  great  granite  batholites,  which  have 
melted  so  much  of  the  gneiss  and  hornblende-schist  into  their  mass  that 
their  composition  has  been  greatly  changed,  but  which,  penetrated  more 
deeply,  would  change  to  ordinary  granite. 

Two  bands  of  hornblende-schist  may  be  traced  right  up  to  the  Belcher- 
town  stock  on  the  south,  and  reappear  again  with  their  attendant  beds  upon 
the  north,  and  a  single  very  thick  bed  can  be  followed  up  to  the  Hatfield 
bed  on  the  north,  and  in  traces  dipping  toward  it  along  its  western  side. 

The  hornblende-schist  west  of  Belchertown  village,  cut  by  numerous 
dikes  of  granite,  becomes  impregnated  with  feldspar,  and  its  fragments  have 
their  hornblende  largely  changed  to  green  pp-oxene  for  a  foot  from  the 
contact  plane  (this  at  Kellys  Crossing),  and  farther  south  beds  of  augitic 

'  See  J.  W.  Jncld,  The  ancient  volcanoes  of  the  Hebrides :  Jour.  Geol.  Soc.  London,  Vol.  XXX, 
1874,  pp.  220-300. 


THE  EEUrTIVE  ROCKS.  311 

granite  nearly  4  feet  thick  border  the  hxrger  granite  veins,  or  are  inter- 
cahited  in  the  amphiboUte,  and  at  hist  the  whole  greatly  resembles  the 
"syenite" — here  a  diallage-biotite-gabbro. 

The  eastern  hornblendic  band  comes  south  as  a  sharp  synclinal  fold  of 
honiblende-schist,  embracing  a  band  of  mica-schist,  and  becomes  changed 
to  resemble  the  tonalite,  while  the  inclosed  schist  continues  far  south  into 
the  tonalite,  metamorphosed  into  a  highly  crystalline  fibrolite-schist. 

On  the  west  side  of  the  river  broad  bands  of  hornblende-schist  and 
limestone  can  be  traced  to  contact  with  the  tonalite,  and  isolated  fragments 
ap2:)ear  on  the  latter  across  its  whole  length.  Farther  west,  beyond  the 
influence  of  the  hornblende-schist,  the  tonalite  changes  to  biotite-granite, 
and  still  farther  west  to  muscovite-granite.  Biotite-granite  becomes  the 
prevailing'  rock  of  the  batholites,  where  they  are  contained  in  the  Conway 
garnetiferous  schists. 

Two  circumstances  are  very  peculiar  in  the  distribution  of  the  rock. 
The  first  is  the  barrenness  of  the  great  central  masses  as  compared  with  the 
richness  in  minerals  of  the  smaller  bordering  dikes ;  the  other,  the  degree  to 
which  the  granite  is  confined  to  the  mica-schist  and  avoids  the  gneiss  which 
bounds  it  east  and  west  and  in  all  probability  underlies  it.  This  association 
is  so  marked  that  when  a  narrow  strip  of  the  Conway  mica-schist  appears 
east  of  the  river  in  Northfield  there  are  associated  with  it  dikes  of  pegmatite 
having  secondary  veins  of  albitic  granite  carrying  cleavelandite,  spodumene, 
columbite,  and  beryl. 

The  western  line  of  Pelham  and  its  prolongation  northward  and  south- 
ward through  Leverett  and  Belchertown  is  the  eastern  boundary  of  the 
disturbed  area,  and  in  the  gneiss  east  of  it  granite  dikes  are  few  and  unim- 
portant, rarely,  as  at  the  Monson  quarry,  can-ying  garnet  and  beryl. 

I  have  given  much  thought  to  those  theories  which  would  trace  the 
granite  down  to  the  subjacent  gneiss  which,  entirely  melted,  is  supposed  to 
have  been  " extra vasated"  into  the  subjacent  rocks;  but  I  find  no  good 
reason  for  inferring  any  intimate  relation  between  the  gneisses  of  the  region 
and  the  pegmatite.  Many  chemical  and  microscopical  peculiarities  of  the 
gneiss  militate  against  that  relation,  such  as  the  large  content  of  quartz, 
calcium,  and  iron  and  the  small  content  of  potassium,  the  uniform  distribu- 
tion of  biotite  and  titanite,  and  the  absence  of  tourmaline  and  muscovite. 

Further  (exception  being  made  of  the  small   secondary  veins  with 


812  GEOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 

their  abundant  minerals),  the  notion  that  any  considerable  ijortion  of  the 
pegmatite  is  "endogenous" — i.  e.,  is  a  granite  veinstone  of  aqueous  origin — 
is  met  by  its  enormous  amount  in  comparison  with  the  schists  from  which 
it  is  supposed  to  be  derived,  and  the  fact  that  it  has  plainly  conduced  to  the 
enrichment  of  the  schists  by  rendering  them  feldspathic  and  abundantly 
quartz- veined  rather  than  to  their  impoverishment.  At  the  same  time,  the 
appearance  of  the  granites  solely  in  the  mica-schist  area  is  a  fact  for  which 
I  have  no  explanation,  except  that  the  granites  have  come  up  along  the 
axes  of  the  larger  synclines. 

HISTORICAL  KOTES   ON"  THE  MICA-GRAIsITES. 

1819.  E.  Hitclicock.     Geology  of  Deerfleld,  etc.     Am.  Jour.  Sci.,  1st  series,  vol.  1, 

p.  IOC. 

1820.  A.  Eaton.    Index,  p.  95. 

1823.  E.  Hitchcock.     Geology  of  the  Connecticut  River.     Am.  Jour.  Sci. ,  1st  series, 

vol.  6,  p.  18. 

1824.  C.  Dewey.    Geology  of  Berkshire  County,  etc.    Ibid.,  vol.  8,  p.  4. 
1824.  E.  Emmons.    Notice  of  localities.    Ibid.,  p.  250. 

1827.  A.  Nash.    Lead  mines  of  Hampshire  County.     Ibid.,  vol.  12,  pp.  238-258. 

1828.  E.  Hitchcock.    Mineral  localities.    Ibid.,  vol.  14,  p.  219. 
1833.  E.  Hitchcock.    Geology  of  Massachusetts,  p.  465. 
1835.  E.  Hitchcock.    Ibid.,  No.  17,  p.  473. 

1841.  E.  Hitchcock.     Ibid.,  Final  Eeport,  p.  682. 
1855.  B.  Emmons.    American  Geology,  p.  64. 
1866,  C.  TJ.  Shepard.    Am.  Jour.  Sci.,  2d  series,  vol.  42,  p.  248. 
1876.  W.  O.  Crosby.     Report  on  Geological  Map  of  Massachusetts,  pp.  30,  38. 
1879.  A.  A.  Julien.     Spodumeue  and  its  alterations.    Annals  N.  Y.  Acad.  Sci.,  vol.  1, 
p.  346. 

In  1819^  President  Hitchcock  mentions  the  granite  as  extending  from 
Southampton  to  Hatfield,  with  veins  of  lead  ore — not  distinguishing  the 
Hatfield  "syenite." 

In  1820  Eaton  uses  the  term  "the  Northampton  Range,"  and  notes 
the  direction  and  extent  of  the  lead  vein  from  Montgomery  to  Leverett  as 
proof  of  the  continuity  of  the  above  range  of  granite.  He  also  notes  the 
three  granite  veins,  with  tourmaline,  in  Goshen  and  Chesterfield. 

In  1823  President  Hitchcock  designates  the  granitic  area  extending 

1  The  year  number  may  serve  as  reference  number  to  the  article  cited  above. 


HISTORICAL  NOTES  ON  THE  MICA-GKANITES.  3 13 

troiu  Soutluuuptou  through  Williamsburg  "the  Southampton  granite,"  and 
considers  it  "an  original  fundamental  deposit  of  this  rock."     He  says: 

I  would  here  suggest  whether  the  mica-slate  of  this  region  that  contains  beds 
of  granite  may  not  be  a  newer  formation  reposing  immediately  upon  that  granitic 
nucleus  which  probably  forms  the  basis  rock  in  New  England.  And  wherever  this 
mica-slato  and  upper  granite  is  worn  away  or  there  is  a  projection  in  the  nucleus  the 
basis  rock  may  appear. 

He  describes  further  the  Amherst-Leverett  range  of  gi-anite,  extending 
it  to  the  mouth  of  Millers  River.  The  gi-anite  veins  abundantly  cutting 
across  all  the  other  rocks  of  the  region  are  discussed  and  figured.  These, 
as,  for  example,  the  main  body  of  the  great  Chesterfield  tourmaline-bearing 
vein,  "are  doubtless  contemporaneous — that  is,  such  as  were  consolidated 
at  the  same  time  with  the  rocks  they  traverse" — a  curious  idea,  based,  I 
presume,  on  the  fact  that  the  Chesterfield  dike  is  interbedded  in  its  schists 
with  apparent  conformity. 

Graphic  gi-anite  in  Deerfield  and  Goshen,  porphyritic  granite  in  a 
range  five  or  six  miles  long  in  Chester  (which  is  a  mistake  for  Middlefield), 
on  authority  of  Dr.  Emmons,  and  " pseudomorphous  granite"  are  described. 
The  latter  is  a  coarse  pegmatite,  in  which  thin  blades  of  biotite  of  the  size 
and  sliape  of  the  blade  of  a  dinner-knife  penetrate  the  rock  in  every 
direction  and  meet  at  every  angle,  but  never  intersect. 

In  1824  Dewey  correctly  locates  the  great  Middlefield  porphyritic 
granite  vein,  doubtless  on  the  authority  of  Emmons,  and  the  latter 
describes  and  figures  many  veins  in  Chester. 

In  1827  Nash  notes  that  often  in  ascending  a  mountain  mica-slate  forms 
the  base,  granite  the  apex,  and  that  the  great  masses  of  granite  are  wholly 
destitute  of  minerals,  and  only  the  veins  in  mica-slate  contain  these. 

In  1833  President  Hitchcock  gives  a  very  complete  and  very  clear 
description  of  granite,  restricting  it  to  the  variety  without  hornblende,  illus- 
trating its  complex  relations  to  the  mica-slate  by  forty-eight  figures,  enumer- 
ating the  minerals  contained  in  it,  and  giving  a  long  argument  in  favor  of  its 
eruptivity.  He  says:  "Upon  the  whole,  the  granite  lies  remarkably  low 
in  respect  to  other  rocks,  and  one  can  not  avoid  the  inference  when  he 
examines  its  situation,  in  almost  all  cases,  that  the  abrasion  of  the  stratified 
rocks  may  have  brought  the  granite  to  light." 

In  1835,  and  again  in  1841,  he  publishes  the  same  description  with 


314       GEOLOGY  OP  OLD  HAMPSHIRE  COUNTY,  MASS. 

scarcely  any  change,  except  to  call  attention  to  the  remarkably  complex 
system  of  veins  at  Grreat  Falls,  in  Russell,  He  recurs  as  follows  to  the  idea 
quoted  above:  "And  I  have  sometimes  inquired  whether,  if  the  whole  sur- 
face were  denuded  as  deep  as  that  part  occupied  by  granite,  we  should  not 
find  this  rock  spreading  over  a  great  part  of  the  State." 

In  1876  W.  0.  Crosby  calls  the  granites  of  western  Massachusetts 
"exotic  montalban  granites,  whitish  or  gray,  seldom  red  or  greenish,  as  the 
Huronian  granite  is  always  micaceous,  seldom  hornblendic,"  and  yet  in  the 
next  section  he  classes  the  "syenite,"  which  is  generally  reddish  or  greenish, 
and  hornblendic,  with  the  montalban  granite.  I  am  not  certain  that  I 
understand  this  classification.  He  says  further:  "The  Williamsburg  granite 
represents,  I  conceive,  the  extension  southward  of  the  Shelburne  anticlinal, 
onl}^  carried  a  step  farther  to  produce  the  extravasated  granite."  An 
inspection  of  the  map  will  show  that  the  Goshen  anticline  is  the  continu- 
ation of  that  at  Shelburne.  There  is  no  anticlinal  structure  connected 
with  the  Williamsburg  granite  and  mica-schist. 

In  1879  Julien  publishes  a  most  valuable  article  on  the  minerals  of 
the  granite  veins  related  to  spodumene,  containing  much  concerning  the 
secondary  veins  themselves  which  I  have  incorporated  in  my  own  descrip- 
tion beyond. 

BIOTITE-MUSCOTITE-GRAlSriTE. 

AREAS  WEST  OF  THE  CONNECTICUT. 

Characteristic  for  this  rock  is  its  fine,  even  grain.  Biotite,  the  prevailing 
mica,  is  scattered  in  small,  separate,  jet-black  scales  in  a  fresh,  bluish-white 
mixture  of  quartz  and  feldspar.  This  gives  it  a  deceptive  similarity  to  the 
granitic  forms  of  the  Becket  gneiss,  from  which  it  is  distinguished  by  its 
greater  firmness  and  by  a  small,  constant  content  of  muscovite.  It  resem- 
bles the  granite  of  Concord,  New  Hampshire.  It  may  be  best  studied  at 
the  quarries  east  of  Florence.  In  its  finest  varieties,  as  at  the  Loudville 
mine,  it  is  almost  a  petrosilex ;  in  its  coarsest,  as  at  the  quanies  above,  the 
grains  reach  2-3™™.  It  is  wholly  wanting  on  the  east  side  of  the  river, 
around  the  Belchertown  tonalite,  which  is  in  immediate  proximity  to  the 
Monson  gneiss. 

DISTEIBUTION. 

Just  east  of  the  Florence  quarries,  and  extending  from  the  house  of 
Mrs.  Haley  to  that  of  W.  N.  Moore,  this  granite  adjoins  the  tonalite.     In  all 


BIOTITE-MUSCOVITE-GRANITE.  315 

tliis  (listiiiu'o  the  exact  contact  is  covered,  but  the  rocks  can  be  studied  at 
points  a  few  feet  from  it,  and  the  change  from  the  one  rock  to  the  other 
seems  to  bo  quite  abrupt. 

From  this  boundary  it  extends  westward  to  the  Mill  River,  and  it  is 
abundantly  exposed  along  the  road  beside  the  river  from  Leeds  to  Williams- 
burg. As  already  indicated,  it  is  found  to  be  more  and  more  replaced  by 
dikes  of  pegmatite  as  one  goes  out  to  the  border  of  the  area  and  up  to  the 
higher  levels. 

It  makes  always  the  impression  that  it  was  the  original  rock,  and  that 
the  pegmatite  was  injected  into  it  at  a  later  time,  pei'haps  only  slightly 
later.  Around  the  periphery  of  the  area  its  dikes  are  very  abundant  in 
Goshen  and  Chesterfield,  and  less  so  in  Conway  and  Blandford.  Its  dikes 
are  so  uniformly  interbedded  in  the  schist  around  the  Goshen  anticline 
that  I  for  a  long  time  mapped  it  as  gneiss,  luitil  at  the  south  end  of  South 
street  in  Chesterfield,  near  C.  Damon's,  I  found  it  cutting  across  the  beds 
of  the  schist.  In  these  dikes  it  is  of  'a  little  finer  grain  and  more  friable 
than  in  the  main  stocks. 

PETEOGRAPHICAL   DESCRIPTION. 

In  the  middle  quarry  west  of  Moore's  and  east  of  Florence  it  is 
medium-grained,  very  fresh  biotite-granite,  with  little  muscovite,  veiy 
feldspathic,  and  showing  abundant  triclinic  striation.  The  quartz  is  rare 
and  occurs  in  rounded  grains,  as  if  resorbed.  It  contains  fluid  cavities  in 
enormous  quantity,  of  grotesque  forms  and  in  large  sheets,  often  with 
bubbles,  some  moving  rapidly,  some  slowly,  and  some  being  stationary. 
They  contain  water  and  carbon  dioxide.  Large,  rigid  needles  of  rutile  also 
occur.  The  feldspar,  mostly  triclinic,  is  centrally  decomposed  into  a  brown, 
opaque  mass  of  kaolin  scales.  The  narrow,  fresh  border  seems  almost  as 
if  it  were  a  secondary  growth.  Extinction,  18°  on  either  side.  Orthoclase 
and  microcline  are  also  present,  but  in  small  quantity,  and  the  large  amount 
of  plagioclase  allies  it  to  the  tonalite. 

CHEMICAL   ANALYSIS. 

Analysis  I,  following,  was  made  by  Mr.  L.  G.  Eakins  from  a  speci- 
men of  the  best  quarry  stone  of  coarser  grain  from  Moore's  quany,  Flor- 
ence, from  which  also  the  slides  were  cut.  It  is  remarkable  how  exactly 
this  analysis  agrees  with  that  of  the  lighter  variety  of  the  Monson  gneiss, 


316 


GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 


witli  which  variety  this  rock  agrees  most  closely.     I  have  repeated,  for 
comparison,  the  analysis  of  the  Monson  rock  (II)  : 

Analyses  of  granite  from  Florence  and  gneiss  from  Monson. 


I. 

II. 

SiOj 

73.27 

.10 

15.51 

.33 

1.14 

Trace. 

2.74 

.15 

1.66 

4.79 

.68 

Trace. 

73.47 

TiOj 

ALO3 

15.07 
V     1.15 

Fe,G3 

FeO 

MnO 

CaO 

4.48 
.12 
..88 

5.59 

MgO 

ICO ...     . 

Na,0 

H,0 

T2O5 

S .' 

Trace. 
Trace. 

Cu 

Total 



100. 37 

100. 26 

TOURMALINE  DENDRITE  ON  THE  SURFACE  OF  A  BLOCK  OF  GRANITE  FROM  LEEDS. 

On  the  surface  of  a  block  of  the  light-gray  granite  quarried  at  Leeds 
is  a  layer,  one-eighth  of  an  inch  thick,  which  differs  greatly  from  the  mass 
of  the  granite.  The  latter  is  a  clear,  gray  granite  of  medium  grain  whose 
mica  is  mostly  a  jet-black  biotite.  The  thin  layer  is  a  slightly  coarser 
muscovite-granite,  and  over  a  large  surface  beautiful  dendritic  growths  of 
jet-black  tourmaline  have  formed.     (PL  VII.) 

It  is  clear  that  boracic-acid  emanations  have  passed  through  a  fissure 
in  the  newly  formed  granite,  and  have  promoted  at  once  the  formation  of 
tourmaline  and  the  replacement  of  the  biotite  of  the  granite  by  muscovite. 


THE  ATHOL  AREA. 


This  enters  the  county  only  in  the  east  portion  of  Orange,  east  of  the 
west  branch  of  Tully  Brook,  and  the  boundary  is  continued  northward 
across  the  west  portion  of  Royalston.  The  granite,  from  more  rapid  erosion, 
forms  a  steep  valley,  out  of  which  rise  the  steep-sided  Big  Tully  and  Little 


BIOTITE  MUSCOVITE-GE ANITE.  317 

Tully  mountains.  The  (li'ainage  established  itself  toward  the  sides  of  the 
basin  and  left  these  mountains  in  its  center,  as  in  the  Orange-Enfield  basin. 
The  result  is  that  the  contacts  with  the  schists  are  everywhere  concealed 
beneath  the  brook  deposits,  and  farther  north  by  the  till. 

From  the  highest  groiuid  on  the  road  north  from  North  Orange  a  fine 
view  is  obtained  of  the  deep  basin,  with  the  white  granite  showing  in  the 
flanks  of  the  Tully  Mountains  and  all  the  ground  above  the  sand  level  a 
"felsenmeer"  of  great  woolsack  bowlders  of  granite,  while  the  bold  hill 
in  the  extreme  northeast  of  Orange  shows  by  its  jagged  ridges  of  rust-brown 
rock  that  it  is  made  up  of  the  higher  fibrolite-schists. 

The  rock  is  the  same  almost  purely  biotitic  granite  as  in  the  other  bands, 
in  the  northern  portion  beautifully  "  stretched"  and  slighl>ly  garnetiferous. 
Along  the  side  of  Little  Tully  Mountain  the  biotite  is  mingled  with  epidote 
in  porphyritic  blotches. 

SECRETIONS   AND   INCLUSIONS. 

I  have  described  below  (p.  332)  the  black  biotitic  secretions  which 
occur  in  the  tonalite  on  either  side  of  the  river,  and  which  resemble  exactly 
those  found  in  this  granite.  They  are  formed  by  the  accumulation  of  biotite 
around  centers.  Other  inclusions  are  more  or  less  angular,  and  are  finer- 
grained  and  less  micaceous  than  their  host,  or  coarser-grained  and  black 
from  excess  of  biotite  and  hornblende.  These  seem  to  be  portions  of  the 
rock  itself  which  have  solidified  before  the  rest  and  have  been  broken  up 
and  floated  to  their  present  position,  with  more  or  less  re-solution. 

There  is  in  the  first  Massachusetts  survey  collection  one  specimen 
from  Whately  which  contains  a  true  inclusion  of  a  foreign  rock — a  highly 
pyritous  muscovite-schist. 

THE   HARDWICK   GNEISSOID   GRANITE   AND   GRANITITE. 

Reference  may  be  made  to  the  section  in  Chapter  VIII  having  the 
above  caption  for  a  preHminary  description  of  this  rock  (p.  239).  It  covers 
a  much  greater  area  in  Worcester  County  than  here,  and  its  relations  will 
be  more  fully  discussed  in  a  memoir  on  the  geology  of  that  county.  The 
rock  could  have  been  described  with  perhaps  greater  propriety  in  this 
chapter  than  with  the  Brimfield  schists. 

The  Coys  Hill  granitite  seems  to  me  somewhat  older  than  the  other 


318  GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

granites  of  this  section,  as  it  is  more  clearly  affected  by  the  last  foldings, 
and  it  cuts  the  Brimfield  schist  and  the  Hardwick  granite-gneiss.  The 
latter  is  thus  materiall}^  older  than  the  other  granites,  and  more  nearly 
contemporaneous  with  the  Brimfield  schist,  in  which  I  suppose  it  to  have 
been  intraded  before  the  final  folding  of  the  series,  and  with  which  I  have 
therefore  described  it. 

BIOTITE-GRAJSriTE,   OR    GEAIflTITB. 

Within  the  central  granite  area  I  have  found  but  one  dike  of  a  purely 
biotite  -  granite,  an  exceptionally  fresh,  coarse,  subporphyritic  rock  with 
white  orthoclase,  much  plagioclase,  and  amber  quartz.  It  occurs  820  feet 
west  of  the  outl.et  of  Burnell's  pond  in  Chesterfield. 

The  granite  described  above — that  extending  west  from  the  tonalite 
through  Florence,  and  that  around  Williamsburg — is  often  in  hand  speci- 
mens a  purely  biotitic  rock;  but  it  generally  contains  at  least  a  small 
amount  of  musco^dte.  This  muscovite  has  always  in  the  freshest  rock  the 
character  of  an  original  component,  and  is  so  regularly  present  that  I  have 
classed  these  rocks  as  two-mica-granites. 

CONTACT    METAMORPHISM    OF    THE    GRANITITE    AND    SCHISTS. 

The  granitite  is  a  highly  feldspathic  rock,  and  it  has  had  great  influ- 
ence U2Don  the  rocks  bordering  it  on  either  side. 

The  rusty  fibrolite-schists  become  garnetiferous  gneisses,  jDorphyritic 
with  a  great  number  of  rounded  masses  of  clear,  fresh,  transparent  ortho- 
clase, which  oi*'en  furnish  good  moonstones,  and  were  foi'merly  quoted  as 
adularia  from  Brimfield  and  Sturbridge.  They  appear  also  in  the  dark 
Hardwick  granite,  where  the  porphyritic  granitite  approaches  it,  and  they 
continiie  to  appear  in  the  fibrolite-gneiss  far  south  of  the  most  southern  point 
to  which  the  granitite  can  be  traced,  across  Brimfield  and  Monson,  as  if 
they  marked  its  subterranean  continuation.  They  are  often  crushed  at  the 
border  into  a  fine,  sugary  mosaic,  and  this  cataclase  structure  is  at  times 
continued  clear  to  the  center. 

THE    MIDDLEFIELD    PORPHYRITIC    GRANITITE. 

The  great  dike  of  granite  in  Middlefield,  about  6  miles  long,  is  widely 
separated  from  all   other  outcrops,  and  is  unlike  all  the  other  masses  of 


BIOTITE-GKANITE.  319 

granite  in  the  region.  It  is  purely  a  biotite-granite,  small -porpbyritic 
in  all  its  central  portions.  The  feldspars  are  about  three-fourtbs  of  an 
inch  long,  rai'ely  show  carlsbad  twinning,  and  are  microcline  without  albite 
bands.  A  few  rounded  spots,  apparently  of  albite,  break  the  continuity  of 
the  cleavage  surface.  These  feldspar  crystals  are  at  times  bounded  by  a 
layer  of  secondary  muscovite  plates,  and  this  is  the  only  appearance  of 
musco\'ite  in  the  granite. 

The  biotite  is  aggregated  in  groups  of  rather  dull-black  plates,  with 
epidote,  garnet,  and  rarely  white  apatite  needles  accompanying  it.  The 
yellowish-white  background  is  a  somewhat  friable  mixture  of  much  gran- 
ular orthoclase  and  little  bluish  quartz,  which  is  characterized  by  the 
presence  of  small,  elongate  cavities.  At  the  border  the  porphyritic  feld- 
spars and  the  biotite  aggregates  disappear,  and  the  friable  ground  with 
small  distant  spots  of  biotite  and  the  small  cavities  remain  unchanged. 

THE  COYS  HILL  PORPHYRITIC  GRANITITE. 
DESCKIPTION  AND   DISTRIBUTION. 

The  Middlefield  dike  on  the  west  of  the  area  is  matched  by  this  still 
larger  dike  on  the  extreme  eastern  border.  It  begins  in  Winchendon,  and 
runs  south  25  miles  across  Phillipston,  Barre,  New  Braintree,  West  Brook- 
field,  and  Warren  before  it  enters  the  Palmer  quadrangle  at  its  northwest 
corner,  and  ends  in  Brimfield.  Its  whole  length  is  33  miles;  its  average 
width  is  one-half  mile.  Only  the  portion  in  the  Palmer  quadrangle  is 
here  studied.  It  is  a  highly  feldspathic,  very  coarse-porphyritic,  garnet- 
iferous  granitite,  which  presents  almost  everywhere  a  distinct  gneissoid 
structure  from  the  parallel  arrangement  of  the  large  feldspars.  It  is  proved 
to  be  an  intruded  rock  by  the  fact  that  it  runs  for  20  miles  in  the  Brim- 
field  fibrolite-gneiss;  then,  just  as  it  enters  the  Palmer  quadrangle,  it  crosses 
very  obliquely  the  Hardwick  black  granite,  and  enters  the  eastern  band  of 
fibrolite-gneiss.  This  is  further  proved  by  the  fact  that  where  it  sends 
a  great  lobe  into  the  western  fibrolite-gneiss  the  boundary  between  the  two 
is  a  broad  sigmoid  curve,  having  a  general  east-west  direction,  while  the 
granitite  on  the  north  and  the  rusty  fibrolite-gneiss  on  the  south  of  this  line 
have  the  same  foliation  structure,  which  strikes  N.  25°  E.  and  dips  60°-70° 


320  GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

west  with  great  uniformity,  and  thus  cuts  directly  across  the  boundary 
between  the  two  rocks  at  every  angle.  The  sudden  disappearance  of 
graphite,  pyrite,  and  fibrolite,  and  rustiness  and  the  great  increase  of  feld- 
spar, separate  it  from  the  Brimfield  gneiss. 

This  gneissoid  structure,  furthermore,  distinguishes  this  dike  from  the 
other  granites  of  the  region  and  indicates  for  it  a  greater  age.  The  other 
granites  have  often  been  injected  into  the  vertical  foliation  planes  of  the 
schists  after  these  had  been  completely  formed,  and  do  not  show  any 
trace  of  having  been  subjected  to  the  pressures  which  have  given  these 
structures  to  the  schists,  while  here  the  granitite  and  the  schists  have  been 
subjected  to  the  same  compression. 

A  crushing  of  the  feldspars  occurs  in  the  bordering  portions  of  the 
granitite  itself,  and  is  well  shown  where,  across  the  brook  north  of  Fenton- 
ville,  in  Brimfield,  the  western  boundary  runs  up  the  mountain  side.  Here 
the  large  feldspars  are  only  slightly  rounded  and  the  sugary  border  of 
crushed  feldspar  still  retains  the  angular  boundary  of  the  former  crystal. 
The  change  increases  until  only  the  transparent  centers  remain,  and  this 
causes  a  marked  whitening  of  the  whole  rock  and  ends  with  the  formation 
of  a  light-gray,  granular  granitite,  hardly  to  be  distinguished  from  the 
Monson  gneiss.  This  forms  a  selvage  to  the  dike  a  hundred  feet  wide  near 
H.  Sherman's,  a  mile  southwest  of  West  Warren,  and  a  large  quarry  has 
been  opened  upon  the  same  rock  on  the  west  slope  of  Colonels  Mountain, 
in  the  northeast  corner  of  Palmer. 

The  rock  can  well  be  described  by  supposing  the  lai'ge  porphyritic 
Carlsbad  twins  which  are  scattered  through  the  rusty  fibrolite-schist  of  East 
Monson  and  Sturbridge  to  develop  so  abundantly  that  a  complete  augen- 
gneiss  should  result,  the  biotite  and  the  garnet  remaining  the  same  as  in 
the  fibrolite-schist,  and  only  the  fibrolite,  graphite,  and  pyrite  disappearing, 
which  they  do  almost  uniformly.  I  have  been  thus  led  at  times  to  consider 
this  rock  an  extreme  of  the  granitic  impregnation  which  has  affected  the 
fibrolite-schists  in  this  region,  and  not  an  intruded  plutonic  rock  pure 
and  simple.  A  granite  dike  33  miles  long  and  only  2,500  feet  wide  is 
rather  anomalous,  especially  in  a  region  where  the  granites  are  in  great 
blocks  of  a  wholly  different  type.  We  are  here,  however,  at  a  point 
where  the  type  changes.  Farther  east  porphyritic  grauitites  are  very 
common. 


BIOTITE-GRANITE.  321 


CORDIERITE-GRANITITE. 


At  Brimfield,  in  the  roadside  near  the  north  line  of  the  town,  is  a 
coarse  granitic  rock  made  np  almost  wholly  of  o-ranular  feldspar,  in  which 
hu-ge,  rounded  crystals  of  the  same  are  embedded.  In  both  forms  the  feld- 
spar is  largely  transparent.  Thin  films  of  biotite,  mostly  changed  to 
(chlorite,  are  shot  through  with  tufts  of  fine  fibrolite.  Garnets  and  flakes  of 
graphite  are  irregularly  disseminated.  Large,  granular  masses  of  nearly 
black,  fresh  cordierite  occur,  which  are  at  times  amethystine. 

The  feldspar  proves  to  be  almost  wholly  microcline,  with  finest  micro- 
perthitic  structure  (which  is  the  cause  of  the  moonstone  luster)  and  with 
crushed  borders,  and  it  contains  unusually  large  and  well-defined  zircons. 
The  quartz  contains  many  long,  curved  rutile  needles. 

The  cordierite  is  exceptionally  fresh;  rarely  there  spreads  in  fissures 
a  delicate,  feathery  growth  of  limonite,  and  the  mineral  is  altered  for  a 
small  distance  into  a  yellow,  serpentine-like  mass  having  aggregate  polar- 
ization. It  contains  in  great  numbers  regular  hexagonal  plates  of  hematite, 
placed  in  two  planes  at  right  angles  to  each  other. 

Interposed  laminae  occur  at  times  in  twin  positions.  (See  fig.  2,  PL  III.) 
There  are  two  sets,  making  an  angle  of  about  61°  with  each  other.  They 
are  long,  rigidly  straight  and  parallel,  narrow  plates,  sometimes  slightly 
tapering  or  truncated  at  the  end  by  an  oblique  plane. 

Sometimes  a  broad  untwinned  area  sends  a  great  number  of  these  thin 
bands  far  into  the  untwinned  area  of  another  crystal. 

At  times  the  bands  interlace  and  include  many  diamond-shaped  fields 
of  the  host.  They  are  unlike  plagioclase  bands  in  that  they  are  sur- 
rounded in  polai'ized  light  by  a  white  band.  This  is  because  the  plane  of 
boundary  runs  obliquely  to  the  plane  of  the  section,  and  the  complementary 
colors  of  two  parts  neutralize  each  other.  The  fibrolite  runs  up,  branching 
and  rebranching  like  a  plant,  and  at  the  end  of  each  branch  bright-green 
plates  of  chlorite  are  attached  like  leaves.  In  some  cases  it  seems  as  if  the 
square  prism  of  the  fibrolite  were  changed  to  chlorite. 

In  fig.  2  of  PI.  Ill  the  unshaded  portion  shows  the  axial  figure  of  the 
fii'st  crystal  (I)  eccentrically  as  indicated.  This  crystal  was  large,  and 
from  a  second,  smaller  crystalline  portion  (II)  blades  generally  rigidly 
straight  and  with  straight  boundaries  were  sent  out  into  (I).     These  plates 

MON  XXIX 21 


322  GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

are  bounded  by  sides  of  the  prism  oo  P,  which  is  the  twinning  plane.  They 
show  a  single  axial  ring,  and  the  axial  plane  makes  an  angle  of  48°  with 
that  of  (I),  instead  of  60°  50',  as  would  be  the  case  if  they  were  cut  par- 
allel to  0  P.  The  other  cr}^stal  (III)  is  represented  by  a  series  of  blades 
which  make  an  angle  of  61°  with  the  first  series.  They  are  also  bounded 
by  <^  P,  which  is  the  twinning  plane,  and  their  optical  axial  plane  makes 
an  angle  of  58°  oia  the  other  side  of  (I).  The  figure  is  drawn  with  crossed 
nicols  and  with  the  crystal  (II)  at  the  point  of  extinction. 

MITSCOVITE-GBAKITE,   OR  PEGMLATITE. 

One  may  omit  any  detailed  description  of  a  rock  so  well  known.  It 
is  a  granular  mixture  of  quartz,  muscovite,  and  a  potash-feldspar  mostly 
microcline,  or  orthoclase  more  or  less  mixed  with  microcline,  and  veined 
with  albite;  generally  coarse-grained,  and  often  very  coarse — a  giant 
granite  with  its  feldspars  several  inches  on  a  side  and  its  mica  a  foot  or 
more  across.  Its  greater  masses  and  its  smaller  dikes  are  almost  wholly 
barren  of  any  accessory  minerals.  In  its  dikes  of  medium  or  larger  size 
several  minerals — as  beryl,  biotite,  tourmaline,  garnet — occur  sporadically, 
and  much  more  rarely  "secondary  veins"  of  foliated  albite  contain  these 
and  others  of  the  rarest  minerals  in  greatest  beauty  and  profusion. 

The  great  masses  which  stretch  from  Montgomery  to  Conway  and  the 
many  dikes  which  go  out  from  them,  the  great  mass  southeast  of  Mount 
Toby  in  Leverett  and  the  north  of  Amherst,  and  the  dikes  extending  thence 
south  through  Amherst  and  Belchertown  are  the  main  outcrops  of  this  rock. 

These  dikes  have  been  extensively  worked  in  Blandford  and  Hunting-- 
ton  for  mica,  feldspar,  and  quartz,  especially  upon  the  property  of  the 
Pontoosic  Flint  Mills,  in  the  north  part  of  Blandford.  There  is  opened 
here  one  of  the  most  beautiful  veins  of  giant  granite  in  the  county.  The 
upper  and  the  lower  walls  are  occupied  by  a  selvage  2  to  3  feet  wide  of 
the  coarsest  muscovite,  which  projects  inward  with  crystals  a  foot  square, 
mingled  with,  feldspar.  There  follows  above  and  below  a  layer  1  to  2  feet 
wide  of  great  feldspars  a  foot  on  a  side,  which  projects  freely  inward.  The 
center,  2  to  6  feet  wide,  is  of  clear,  smoky  quartz,  and  in  one  direction  the 
whole  vein  changes  to  quartz. 

These  veins  are  very  rare  in  the  tonalite,  but  going  out  from  these 
into  the  granites  they  increase  gradually  in  ntimber  and  at  last  swarm  in 


PEGMATITE.  323 

several  <;-om'riiti()us  iiiid  of  every  size  until  the  original  granite  alinowt  cli;s- 
aj)jK'ars,  and  they  appear  in  great  numbers  also  far  beyond  the  great  granite 
stocks,  in  the  schists. 

While  nuiscovite  is  so  rare  as  to  be  almost  an  accessory  in  the  granitite, 
biotite  is  not  wholly  wanting  here,  but  appears  always  with  the  distinct 
habit  of  an  accessory,  in  great  blades  touching  each  other  so  as  to  form  a 
rude  cellular  structure.  This  was  called  pseudomorphous  granite  by 
Hitchcock. 

I'EOBABLE    EXTREME    MODIFICATION    OF    THE    PEGMATITE    BY    CRUSHING. 

The  North  Amherst  granite. — This  is  a  peculiar  rock,  appearing  in  the 
hills  southeast  and  west  of  North  Amherst  station,  and  again  at  the  foot  of 
the  west  slope  of  the  Pelliam  ridge  east  of  D.  Hawley's,  beside  a  brook. 

It  has  at  times  a  quite  marked  foliation  (almost  certainly  a  secondary 
structure),  distant  planes  being  thickly  covered  with  quite  coarse  muscovite- 
biotite  films,  while  in  cross-section  it  appears  wholly  free  from  mica  and 
has  a  subporphyritic  look.  Opaque,  subangular  portions  of  feldspar  or 
quartz-feldspar  are  scattered  quite  distantly  in  a  highly  crystalline  and  con- 
tinuous quartz  mass  which  seems  a  secondary  constituent  cementing  the 
brecciated  fragments  of  a  highly  feldspathic  granite  from  which  most  of  the 
hornblende  or  biotite  has  been  removed  during  the  violent  changes  the 
rock  has  undergone. 

In  thin  section  a  few  twisted  fragments  of  much  altered  biotite  appear. 
The  feldspars  are  brown  with  alteration  products — rust,  kaolin,  and  musco- 
vite — and  rarely  determinable ;  more  plagioclase  can  be  made  out  with  the 
lens  in  the  mass  than  under  the  microscope  in  thin  section.  The  grains  are 
much  cracked  and  crushed,  and  show  undulatory  extinction  and  wavy  twin 
laminae.  Everything  accords  with  its  position  along  the  main  fault  area 
marked  by  strong  crushing. 

ALBITIC    GEAIiTITE  AJND    PEGMATITE    DIKES    CONTAINIlSrG    RARE 

MINERAES. 

It  is  a  remarkable  fact  that  the  rare  elements  appear  only  in  pegmatite 
dikes  on  the  extreme  periphery  of  the  great  granite  area,  and  that  they  are 
not  found  in  the  biotite-granite  or  within  the  great  central  region  of  granite. 
This  is  enforced  by  the  list  of  localities  below,  and  may  be  brought  into 


324  GEOLOGY  OP  OLD  HAMPSHIEE  COUNTY,  MASS. 

casual  connection  with  fumarole  activity,  using  the  term  in  a  wide  sense, 
and  indicates  that  the  pegmatite  dikes  were  the  later  products  in  the  com- 
plex series  of  granitic  types  present  in  the  region.  It  has  some  analogy 
with  the  fumarole  products  accomjjanying  the  trap  eruptions  in  which,  as  I 
have  described  (p.  423),  albite,  clearly  water-deposited,  rests  on  delessite  in 
amygdaloid  cavities,  as  do  also  datolite,  axinite,  and  rarely  tourmaline — 
boracic  acid  minerals.  The  cleavelandite,  which  is  a  variety  of  albite,  and 
abundant  tourmaline  match  the  minerals  named  above,  but  the  analogy 
does  not  extend  to  the  rarer  elements. 

DISTRIBUTION  AND  DESCRIPTION. 

Because  of  several  peculiarities  in  the  separate  occurrences,  I  have 
given  below  a  description  of  each,  commencing  at  the  northwest  and 
going  around  the  area  by  the  south. 

I.    THE    URBAT    TOTJKMALINB-SPODUMENE    DIKE. 

Macomber's  spoduniene  ledge,  Clarke's  tourmaline  ledge,  the  West 
Chesterfield  Hollow,  and  the  well-known  Walnut  Hill  spodumene  ledges 
(the  last  in  what  is  now  Huntington,  the  others  in  Chesterfield)  are  all 
portions  of  one  continuous  or  nearly  continuous,  vertical,  interbedded  dike 
of  coarse  pegmatite,  which  is  faulted  and  its  south  half  thrown  east  at 
West  Chesterfield  Hollow. 

A.  A.  Julien^  says  : 

At  Macomber's  ledge  the  coarse  orthoclase  granite  of  the  main  vein  contains 
films  of  margarodite  and  few  imperfect  green  beryls,  while  in  the  secondary  vein 
the  succession  seems  to  have  been,  first,  quartz,  muscovite,  granular  albite,  tourma- 
line, and  spodumene;  then  cleavelandite,  quartz,  manganese,  garnet,  and  zircon; 
and,  finally,  smoky  quartz  with  green  and  blue  tourmaline.  The  larger  crystals  of 
most  of  these  minerals  penetrate  through  all  the  layers  and  their  growth  seems  to 
have  been  continuous. 

At  Clarke's  ledge  the  main  granite  vein  is  of  the  same  general  constitution 
as  at  Macomber's,  rarely  showing  a  few  large  beryls.  In  the  secondary  vein  no 
spodumene  occurs,  but  the  succession  is  in  the  same  order.  First,  on  either  wall  a 
saccharoidal  albitic  granite,  with  little  quartz  and  mica  and  a  few  scattered,  imper- 
fect black  tourmalines  and  garnets,  then  coarse  cleavelandite,  with  blue,  green,  red, 
and  rarely  brown  tourmaline,  and  small  quantities  of  the  rarer  minerals,  microlite, 
columbite,  cassiterite,  zircon,  cookeite,  lepidolite;  all  these,  especially  the  tourmaline, 
increase  in  quantity  toward  the  center  of  the  vein,  which  is  filled  up  by  an  irregular 
sheet  of  smoky  quartz. 


\  Spotlumene  and  its  alterations:  Annals  N.  Y.  Acad.  Sci.,  Vol.  I,  p.  351. 


PEGMATITK  D  IKES  CONTAINING  KAliE  MINERALS.  325 

Here  the  aclii.sts  havu  bt'on  worn  iiway  from  the  niaiu  (Uke,  which 
stands  up  in  a  vertical  wall  33  feet  high.  In  many  places  a  veneering 
of  schist  remains  attached,  and  when  it  is  removed  the  impression  of  the 
schist  is  sharp  and  clear  on  the  surface  of  the  pegmatite.  The  la}'er  of 
schist  against  which  the  pegmatite  rests  shows  no  signs  of  its  influence,  thus 
differing  from  the  schist  in  contact  with  the  albitic  granite  at  the  Barrus 
farm,  described  below,  where  the  contact  metamorphism  is  pronounced 
and  the  granite  and  schist  are  fused  together. 

The  secondary  vein,  as  described  above,  is  seen  high  up  on  the  face  of 
the  vertical  side  of  the  main  dike,  and  seems  to  me  to  have  been  deposited 
in  a  vertical  transverse  fissure  in  the  latter,  which  fissure  extends  from  the 
east  face  only  about  halfway  across  the  dike  and  to  an  intermediate 
distance  up  and  down.  This  fissure  seems  to  have  been  formed  in  the 
newly  consolidated  pegmatite  and  to  have  been  filled  by  a  magma  of 
peculiar  composition,  much  hydrated,  rather  than  by  a  simple  solution. 
Thus,  commencing  with  this  tonahte  and  ending  with  the  quartz  veins,  I 
suppose  there  is  an  unbroken  series  from  igneous  fusion  to  aqueous  solution. 

At  Chesterfield  Hollow  the  granite  of  the  main  vein  is  of  the  usual  character, 
bat  shows  no  beryl  and  little  mica.  The  successive  deposition  of  minerals  in  the 
secondary  vein  is,  first,  orthoclase  in  huge  crystals,  large  plates  of  muscovite,  some- 
times 6  to  10  inches  in  diameter,  and  grayish-white  quartz.  Within  this  comes  an 
irregular  mass  of  a  coarse  albitic  granite,  with  green  muscovite,  spodumene, 
greenish-white  beryl  in  masses  sometimes  10  to  25  pounds  in  weight,  and  a  zircon 
rich  in  uranium  iu  minute  double  pyramids  rarely  three-sixteenths  of  an  inch  in 
diameter.  Usually  this  albitic  granite  passes  gradually  into  a  mixture  of  quartz 
and  cleavelandite  iu  bunches  of  snow  white  plates  inclosing  less  muscovite— 
manganese  garnets  in  large  and  abundant  but  imperfectly  crystalline  grains, 
zircon,  spodumene,  and  yellowish-white  beryl  in  irregular  masses. 

Finally  the  core  of  the  vein  consists  of  an  irregular  sheet  of  smoky  quartz, 
penetrated  by  long  prisms  of  spodumene,  green  beryl  in  small  and  good  crystals, 
muscovite  in  hexagonal  plates,  often  well  crystallized  and  up  to  2  or  3  inches  across, 
as  well  as  in  sheets,  scattered  scales  and  wavy  films  which  in  part  seem  to  be  altered 
to  margarodite,  columbite,  and  zircon  in  rare  but  perfect  crystals.  This  succession 
of  minerals  in  the  secondary  vein  is  not  as  regular  as  might  be  inferred  from  the 
foregoing  description,  in  which  it  is  intended  to  indicate  only  the  general  tendency 
toward  a  definite  arrangement. 

At  Walnut  Hill,  in  Huntington,  the  material  of  the  main  vein  is  similar  to 
that  of  the  preceding  locality.  In  the  secondary  vein  the  rich  deposit  was  found 
to  be  a  very  coarse  albitic  granite,  rich  iu  black  tourmaline  in  huge  masses,  mus- 
covite, and  garnet;  then  followed  cleavelandite,  white  quartz,  and  spodumene  iu  the 


326  G^BOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

well-known  fine  crystals  associated  with  black  and  blue  tourmaline,  triphylite,  cryto- 
lite,  garnet,  apatite,  niuscovite,  and  greenish-white  beryl,  and  the  central  sheet  of 
smoky  white  quartz  received  the  terminations  of  the  spodumene  crystals,  together 
with  a  little  beryl,  moscovite,  and  cyrtolite.' 

II.  DIKES   IN   GOSHEN. 

The  first  dike  in  Groshen,  that  on  the  Manning-  farm,  west  of  the  Ash- 
field  road,  near  the  north  line  of  the  town,  can  not  be  well  studied,  as  only 
disconnected  masses  can  be  obtained  and  the  boundaries  of  the  dike  are 
not  visible. 

The  veinstone  consists  of  a  coarse  aggregate  of  albite,  iudicolite,  garnet,  and 
spodumene,  whose  crowded  and  imperfectly  outlined  grains  indicate  a  more  rapid 
crystallization  than  in  the  other  localities. 

At  the  Barras  vein,  a  mile  to  the  west,  the  mass  of  the  vein  seems  to  be  repre- 
sented in  j)lace  by  a  coarse  aggregation  of  white  quartz,  orthoclase,  and  muscovite, 
and  occasionally  greenish  beryl,  accompanied  in  places  by  a  contiguous  vein  of  red- 
dish-white quartz,  while  the  scattered  bowlders  of  albitic  granite  appear  to  be  frag- 
ments of  a  central  band  or  secondary  vein  whose  slow  crystallization  is  suggested 
by  the  beautiful  aggregate  of  snow-white  cleavelandite  and  grayish-white  quartz 
which  forms  the  matrix  of  the  rarer  minerals.  Of  these  the  most  abundant  are  the 
spodumene,  mostly  in  rectangular  prismatic  masses  up  to  18  inches  in  length,  and 
tourmaline  in  black,  green,  or  blue-black  (indicolite),  generally  massive,  but  sometimes 
in  good  crystals.  Less  commonly  were  found  beryl,  green  and  white  (goshenite),  in 
grains  or  sometimes  fairly  crystallized,  with  good  terminations,  garnet,  rose-colored 
muscovite,  and,  still  more  rarely,  columbite  and  cassiterite  in  minute  crystals.  Appar- 
ently there  has  been  also  in  parts  of  the  vein  a  final  deposition  of  masses  of  smoky 
quarts  enveloping  smaller  crystals  of  these  minerals,  but  particularly  of  green  beryl 
and  indicolite.^ 

Here  the  secondary  vein  came  in  part  in  contact  with  the  countr}^  rock, 
and  the  latter,  which  is  a  whetstone-schist  just  at  the  contact,  has  been  for 
several  inches  (at  least  4)  fully  impregnated  with  silica,  albite,  and  tour- 
maline in  fine,  black  needles. 

Halfway  between  the  Manning  and  the  Barrus  ledges,  by  the  road- 
side, south  of  J.  B.  Taylor's,  much  blasting  has  been  done  recently  (1889) 
by  Mr.  Barrus  for  spodumene.  It  was  proposed  to  export  the  mineral  for  the 
manufacture  of  lithium.  The  spodumene  is  abundant  in  poorly  bounded 
crystals  and  coarse  crystalline  aggregates  associated  with  little  tourmaline, 

'  A.  A.  Julien,  Spodumene  and  its  alterations:  Annals  N.  Y.  Acad  Sci.,  Vol.  I,  p.  351. 
■^A.  A.  Julian,  ibid.,  p.  350. 


PEGMATITE  DIKES  CONTAINING  KARE  MINERALS.  327 

"•ariR't,  aiul  iiiuscovite.     The  three  loccihties  hist  luentionetl  he   in  a  line, 
trending  about  N.  70°  W.,  and  may  be  parts  of  one  vein. 

A  new  locality  discovered  by  me  is  in  a  pegmatite  ledge  a  mile  south 
of  the  Barnis  ledge  and  overlooking  Lily  Pond.  Here  i^rismatic  pseudo- 
morphs  of  coarse  inuscovite  after  spoduraene,  2  niches  long,  occur  in  limited 
number. 

III.    DIKES    IN   CHESTER,    BLANDFORD,   AND    HUNTINGTON. 

The  locality  mentioned  by  E.  Emmons^  as  occurring  a  mile  north  of 
Chester  village  was  stated  by  him  to  contain  spodumene,  smoky  quartz, 
muscovite,  cleavelandite,  and  indicolite.  This  ledge  I  was  not  able  to 
find.  Mr.  A.  A.  Julien  seems  to  have  had  better  success,  but  to  have 
found  no  spodumene  there.^  Not  far  from  this  locality  the  granite  veins 
have  furnished  large  and  perfect  manganesian  garnets. 

Farther  south,  on  the  northeast  line  of  Blandford,  a  very  coarse  peg- 
matite, much  quarried  for  mica,  quartz,  and  feldspar,  the  property  of  the 
Pontoosic  Flint  Mills  (see  page  322),  has  furnished  beryls  of  great  size, 
the  largest  as  big  as  a  powder  keg,  with  large  garnets.  A  granite  in  the 
churchyard  in  Blandford  also  carries  beryl.  .Just  south  of  the  first  house 
on  the  Westfield- Russell  road  after  entering  Russell  the  pegmatite  abounds 
in  manganesian  garnets  of  lai'ge  size  and  great  perfection,  which  are  found 
in  every  cabinet. 

IV.   DIKES   EAST   OF   THE    CONNECTICUT. 

On  the  other  side  of  the  area  the  small  pegmatite  veins  at  the  Monson 
quarry  have  furnished  very  fine  beiyls  and  many  manganesian  garnets. 
The  finest  bluish-white  cleavelandite  occurs  in  New  Salem.  In  Northfield, 
where  the  Gulf  road  crosses  the  south  line,  large  beryls  occur  in  the  peg- 
matite, and  farther  north,  a  mile  west  of  the  Moody  homestead,  is  the  inter- 
esting locality  of  columbite  in  a  pegmatite  vein  in  the  mica-schists,  and  a 
mile  north  on  the  strike  of  the  schists  is  a  secondary  vein  of  the  fine 
radiate-foliate  cleavelandite  of  very  considerable  size,  exactly  like  the 
Goshen-Chesterfield  schists,  in  which  I  could  find  no  other  minerals. 
Still  farther  north,  on  the  strike  and  therefore  in  the  same  schists,  is  a 

'Am.  Jour.  Sci.,  Ist  series,  Vol.  VIII,  1824,  p.  243. 

=A.  A.  Julien,  Spodumene  audits  alterations:  Annals  N.  Y.  Acad.  Sci.,  Vol.  I,  p.  221. 


328  GEOLOGY  OP  OLD  HAMPSHIRE  COIHsTTY,  MASS. 

pegmatite  vein  abounding  in  albite  and  spodumene  and  closely  resembling 
the  occurrence  at  the  Manning  farm,  described  above  (see  p.  326).  This 
lies  just  across  the  north  line  of  Northfield,  near  the  house  of  M.  A.  Brown, 
on  the  Winchester  road. 


GARNET  IN    PEGMATITE  WITH  COMPLEX  PARAMORPHIC  BORDER  OF  ZOISITE- 
HEMATITE,  EPIDOTE-FIBROLITE,  AND    MUSCOVITE. 

In  the  coarse  inuscovite-granite  that  occurs  on  the  Gulf  road  in  the 
southern  part  of  Northfield  and  cuts  the  Goshen  mica-schist  which  farther 
east  becomes  fibrolitic  and  is  called  the  Brimfield  schist,  several  interesting 
garnets  have  been  recently  discovered  by  Mr.  C.  H.  Webster.  (PI.  II, 
fig.  4.)  They  are  nearly  an  inch  across,  of  deep-red  color  and  of  trajDezo- 
hedral  form,  with  a  narrow  dark-red  band  surrounding  them  which  is  in 
places  spotted  with  green.  Outside  this  is  an  opaque  white  border,  3-7™°" 
broad,  which  looks  like  saussurite. 

The  garnet  under  the  microscope  is  evenly  cleaved  and  almost  free 
from  inclusions.  There  are  a  few  rounded  blebs  of  the  quartz-muscovite 
mixture  or  of  the  zoisite-hematite  mixture  which  is  found  in  the  border. 

This  border  layer  is  largely  composed  of  zoisite  in  stout  grains,  which 
shows  low  polarization  colors,  high  refraction,  a  divergence  of  optical  axes 
of  45°,  and  is  optically  positive.  The  hematite  is  deep-red  to  black,  and 
occupies  regular  and  close  cleavage  fissures  in  the  zoisite,  often  so  regular 
as  to  recall  the  cross-section  of  a  tabulate  coral.  This  layer  is  joined  to 
the  garnet  by  a  suture,  which  is  very  intricate,  so  that  lobes  of  the  two 
minerals  penetrate  deepl)-  into  each  other  and  rounded  blebs  of  the  zoisite 
are  cut  off  in  the  garnet.  While  thus  intricately  joined  interiorly,  the 
zoisite  mixture  forms  exteriorly  quite  smooth  crystal  faces  for  the  garnet. 

Outside  this  first  layer  is  a  delicate  and  very  thin  layer  of  green 
epidote,  which  folds  into  every  irregularity  of  the  last  layer  and  extends 
continuously  over  all  the  surface  of  the  latter  and  around  all  inclosed  por- 
tions of  the  same.  It  has  rather  moderate  absorption  and  extinguishes  in 
proper  relation  to  the  cleavages  for  epidote.  The  outer  layer  is  a  mass  of 
muscovite  blades  felted  with  a  fine-fibrous  mass  of  fibrolite  needles  arranged 
in  beautiful  plumose  and  tufted  groups  in  a  general  way  radially  to  the 
surface  of  the  garnet. 


ALBITIC  GRANITE.  329 

THE    CRUSHING    OF    MINERALS    IN    THE    ALBITIC    GRANITE. 

la  tlie  suiiiiuer  of  188;j  the  pegmatite  dike  oil  Walnut  Hill,  in  Hunt- 
ing'ton,  was  reopened  for  nie  by  Mr.  Frank  L.  Nason.  The  spodumene 
crystals  obtained  were  large — larger  than  most  of  those  obtained  previously. 
They  were  clear-gray,  without  the  shade  of  flesh-color  of  those  before 
obtained,  and  were  covered  with  dendrites,  which  also  penetrated  every- 
where into  theperfect  cleavage.  Several  fine  twins  occurred,  but  for  the 
most  part  they  were  not  well  terminated.  The  largest  crystal  was  28  by 
7i  by  oh  inches.  The  crystals  bear  abundant  evidence  of  the  violent 
pressure  to  which  they  have  been  subjected  since  their  formation,  several 
large,  perfectly  terminated  crystals  a  foot  long  being  several  times  obliquely 
sheared  off  and  the  parts  slipped  one-eighth  to  one-fourth  of  an  inch  and 
recemented;  and  the  largest  crystal,  whose  dimensions  are  given  above,  is 
broken  across  or  sharply  folded  into  "monoclinal  flexures"  more  than  forty 
times.  Other  large  crystals  are  bent  over  as  much  as  45°  in  a  great  curve, 
one  sharply  a  full  90°,  and  without  a  crack.^ 

The  feldspar  (microcline)  occurs  in  masses  as  large  as  one's  head,  often 
in  part  green.  The  cleavelandite  is  not  distinguishable  from  that  of  Chester- 
field. Tourmaline  appears  in  large,  rude,  black  crystals.  Granular  ixiasses 
of  honey-yellow  manganesian  garnet  (intermixed  with  feldspar)  as  large  as 
an  egg  have  by  their  decomposition  furnished  the  material  for  the  abun- 
dant dendi'ites.  These  latter  masses  are  at  times  punched  into  the  great 
spodumenes  as  if  these  had  been  plastic  as  wax. 

There  is  in  the  collection  at  Amherst  a  crystal  of  tourmaline  from  the 
Clarke  ledge,  once  figured  by  President  Hitchcock,^  which,  is  broken  across 
fifteen  times  and  the  parts  moved  into  a  position  en  dchelon  and  recemented 
by  quartz,  and  I  have  a  crystal  of  beryl  from  Huntington  similarly  affected. 

HYDROTHERMAL  CHANGES  IN  THE  ALBITIC  GRANITE  VEINS. 

Pseudomorphs. — Julien  has  described  a  most  interesting  series  of  pseudo- 
morphs  in  these  dikes,  produced  by  alkaline  (mainly  sodic)  silicate  solutions, 
by  which  spodumene  is  changed  into  cymatolite,  killinite,  albitic  granite, 
muscovite,  albite,    and   quartz,   the    lithia   being   replaced   by  the    other 

'  For  figures  of  these  crystals  see  Minerological  Lexicon,  iiuder  "  Spodumene" :  Bull.  U.  S.  Geol. 
Survey  No.  126,  1895,  p.  159. 

=E.  Hitchcock,  Geol.  Mass.,  p.  702. 


330  GEOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 

alkalies.  Immediately  afterwards  Brush  and  Dana  proved  the  cymatolite 
to  be  a  mixture  of  albite  and  muscovite  formed  from  the  spodumene  with 
the  intervention  of  a  lithia-  nepheline  (eucryptite),  and  made  it  probable 
that  the  killinite  was  mainly  hydrated  muscovite,  and  thus  the  series  of 
pseudomorphs  is  reduced  to  one  type,  namely,  spodumene  changed  to 
albitic  granite,  whereby,  from  the  gradual  suppression  of  any  one  or  two  of 
the  constituents,  forms  made  up  of  either  quartz,  mica,  albite,  or  mica  and 
albite  result.  Pseudomorphs  a  yard  in  length  and  nearly  a  foot  across  are 
made  up  of  a  coarse  mixttire  in  various  proportions  of  albite,  muscovite, 
and  quartz,  with  manganese,  garnet,  zircon,  beryl,  etc.,  occasionally  inter- 
posed, and  we  may  add  also  microcline. 

ORDINARY   METEORIC  ALTERATION. 

By  ordinary  carbonated  waters  there  has  been  a  gradual  removal  of  a  part  of  the 
lithia  and  more  soluble  protoxides,  almost  universal,  with  the  consequent  effect  upon 
the  physical  characteristics  of  the  mineral  shown  by  the  loss  of  weight,  luster,  greenish 
color,  and  translucency. 

The  zircons  have  absorbed  water  and  lost  part  of  their  uranium,  which  has  sep- 
arated as  autunite,  torbernite,  and,  by  a  further  decomposition,  uranocher.  The 
garnets  afford  ocher  and  pyrolusite  in  dendritic  films. 

The  triphylite  by  absorption  of  water  and  higher  oxidation  of  some  constituents 
has  assumed  its  present  altered  form,  so  that  only  rarely  do  small  blue  nuclei  of  the 
unaltered  mineral  remain. 

The  spodumene  and  cymatolite  both  at  last  degeiierate  into  clayey  material, 
sometimes  pink  and  allied  to  kaolin  or  montmorrillouite.' 

The  kaolin  beds  at  Blandford  village  illustrate  on  a  large  scale  the 
results  of  the  agencies  described  in  the  last  section.  Grreat  beds  of  coarse 
granite  in  every  stage  of  alteration  are  exposed  in  the  diggings;  in  some 
parts  the  feldspars  are  onlf  softened  and  made  friable,  in  others  they  are 
pure  soft  kaolin,  and  the  mica-schist  Avhich  is  tangled  among  the  big  veins 
is  rotted  to  a  soft,  rusty  earth.  All  the  fissures  in  the  altered  mass  are 
blackened  by  deposits  of  manganese  oxide.  It  is  quite  certain  that  this 
deep-seated  alteration  of  the  granite  is  mainly  pre-Glacial  and  owes  its 
preservation  to  its  position  on  the  southeastern  slope  of  the  hill  upon  which 
the  village  is  built.  The  material  has  been  used  extensively  at  Russell  for 
the  manufacture  of  brick  of  fine  quality  and  tile,  but  recently  the  buildings 
have  been  destroyed  by  fire. 

'  A.  A.  Julien,  Spodumene  and  its  alterations:  Annals  N.  Y.  Acad.  Sci.,  A''ol.  I,  p.  353. 


APLITE,  QUAKTZ-PORPHYKY,  AaS'D  TONALITE.  331 

APIilTE. 

Coarse  peg'inatite  dikes  are  rare  in  the  tonalite  areas.  Their  place  is 
taken  ])y  aphte  dikes,  which  in  many  places  are  very  abundant  in  the 
toiiaUte,  but  are  always  very  narrow.  The  rock  is  a  fine-grained  quartz- 
t'cldspar  mixture,  almost  without  hornblende  or  mica.  Two  miles  north  of 
Leyden  Center  a  road  runs  west  down  to  Green  River.  Following  this 
road  a  halt'  mile  west,  one  reaches  a  place  where  it  bends  sharply  south 
around  a  projecting  spur  of  rock.  A  dikelike  mass  which  has  in  part  the 
aspect  of  an  aplite  and  in  part  that  of  a  quartz-porphyry  crosses  the  road  at 
this  point.  It  is  13  rods  wide,  and  stands  vertical  in  the  Conway  schist 
and  strikes  north  with  it.  The  dike  ends  in  the  bluffs  to  the  south,  but 
can  be  followed  a  long  way  north.  It  is  a  pale-gray,  rather  small- 
porphyritic  rock,  and  is  the  only  rock  of  this  type  in  the  area.  I  have 
sometimes  thought  it  an  exceptionally  massive  arkose-gneiss. 

QUARTZ-GABBEO  AND   QUARTZ-DIORITE,   OR  TOIS^ALITE. 

The  syenite  of  President  Hitchcock  seems  to  me  to  have  been  origi- 
nally a  quartz-diallage  rock,  but  it  is  now  for  the  larger  part  a  hornblendic 
rock;  indeed,  west  of  the  river  the  presence  of  diallage  can  only  rarely  be 
rendered  certain.  The  low  percentage  of  silica  and  the  almost  complete 
absence  of  orthoclase  exclude  it  from  the  syenites. 

HISTORICAL. 

BASIC    SECEETIONS:   HITCHCOCK'S    SUGGESTION   OF    THE    THEORY   OF   "SOHLIEREN- 

GANGE." 

In  1819  President  Hitchcock  mentions  "syenite"  as  the  prevalent  rock 
along  the  Connecticut  on  the  east  side — a  statement  scarcely  correct — and 
notes  that  the  proportion  of  hornblende  is  rather  small  and  that  mica  is 
often  present.  "Porphyritic  syenite  is  common  in  this  quarter  and  steatite 
occurs  in  its  eastern  part."  The  first  statement  is  afterwards  retracted,  and 
the  second  I  can  not  explain.^ 

In  1823  the  same  author  describes  the  rock  more  fully  from  its  two 
localities,  Whateiy  and  Belchertown.  He  notes  first  the  interesting-  fact 
that  in  coming  from  the  westward  across  Northampton  ' '  one  passes  over 
the  most  decided  granite  until  he  comes  within  4  or  5  miles  of  the  village. 

'  Geology  of  the  Connecticut  River:  Am.  Jour.  Sci.,  1st  series,  Vol.  I,  1819,  p.  106. 


332  GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

He  will  then  find  the  texture  of  the  rock  to  be  finer,  and  in  some  instances 
it  contains  a  portion  of  hornblende,  while  the  proportion  of  quartz  is  dimin- 
ished somewhat  and  the  feldspar  frequently  becomes  red.  Coming  nearer 
Northampton,  however,  we  find  the  hornblende  more  and  more  abundant 
until  we  arrive  at  the  eastern  edge  of  the  range,  where  we  find  a  rock 
containing  little  else  than  feldspar  and  hornblende." 

He  notes  the  abundant  veins  of  granite  in  the  brook  2  miles  south  of 
the  church  in  Whately,  and  the  many  minute  faults  of  the  rock  and  its 
peculiar  conglomerated  character.  "The  rock  here  contains  numerous 
embedded  masses  of  other  primitive  rocks,  as  gneiss,  mica-slate,  quartz, 
hornblende,  and  a  finer  kind  of  syenite,  all  almost  uniformly  rounded." 

He  mentions  a  third  locality  of  syenite  west  of  the  road,  a  mile  north 
of  the  village  of  Whately,  associated  with  "greenstone-slate  nearly  allied 
to  hornblende-slate,  and  unstratified  primitive  greenstone.  It  consists  of 
nearly  equal  proportions  of  feldspar  and  hornblende — the  former  white 
and  compact  or  very  finely  granular,  entirely  destitute  of  foliated  structure 
or  pearly  luster."^  A  study  of  this  rock  in  thin  section  shows  it  to  be  an 
amphibolite.  The  white  spots  of  supposed  feldspar  are  parts  of  the  finely 
granular  ground  mass,  which  are  free  from  green  hornblende,  and  it  is  not 
diff'erent  from  the  other  beds  of  amphibolite  named  above,  with  which  it  is 
associated.     (See  p.  191.) 

In  the  Reports  of  1833^  and  1835  an  extended  account  of  the  rock  is 
given,  which  is  reprinted  almost  verbatim  in  the  Report  of  1841,^  with  the 
suppression  of  a  single  very  suggestive  theory. 

He  describes  the  rock  as  a  quaternary  compound  of  feldspar,  horn- 
blende, quartz,  and  mica.  He  describes  the  "conglomerated  sienite"  of 
Whately  in  detail: 

It  is  iu  fact  a  real  conglomerate,  and  in  some  places  the  nodules  are  so  numerous 
that  it  has  very  much  the  aiDpearance  of  the  coarse  pudding-stones  of  the  newer  rocks. 
The  nodules  vary  in  size  from  the  diameter  of  half  an  inch  to  that  of  6  or  8  inches. 
They  are  not  smoothed,  like  the  pebbles  in  the  more  recent  conglomerates,  by  mechan- 
ical attrition,  but  they  appear  like  masses  of  rocks  that  have  been  partly  melted  down 
by  heat.  Upon  the  whole,  I  think  I  have  ascertained  the  presence  of  hornblende- 
slate,  mica-slate,  and  quartz  rock  in  these  nodules.  When  the  rock  is  broken  they 
are  knocked  out  without  difficulty,  like  the  pebbles  of  a  common  conglomerate. 

•  Geology  of  Connecticut  River:  Am.  Jour.  Sci.,  1st  series,  Vol.  VI,  p.  29. 
^Eept.  Geology  of  Massacliusetts,  p.  463 
'Ibid.,  p.  668. 


TONALITE.  333 

Tlu'  inclusions  niny  iuivo  been  rounded  by  slow  solution  in  the  melted 
niiU'iua,  this  solution  attacking  corners  and  edges  most  rapidly.  That  the 
iuclosino-  rock  is  an  igneous  rock  is  certain  from  its  microscopical  character 
and  its  contact  effect.  That  the  i)ebble-like  masses  are  true  foreign  "inclu- 
sions" does  seem  pi'obable  from  their  lithological  variety  and  difference 
from  the  inclosing  rock.  They  closely  resemble  pebbles  rounded  by  water, 
but  so  many  cases  of  such  inclusions  rounded  by  melting  (as  granite  in 
lamprophyre  and  quartz  in  various  magmas)  have  been  described  that  this 
may  be  the  explanation.^ 

I  am,  however,  more  inclined  to  consider  them  secretions  in  the  mass 
of  the  rock  itself,  as  they  seem  to  belong  wholly  to  two  types  which  occur 
commonly  in  this  way.  The  one  is  a  coarse,  black  hornblende-biotite 
aggregate,  such  as  is  often  seen  in  small  masses  anywhere  in  the  rock. 
Slides  of  this  showed  it  to  agree  with  these  concretionary  masses,  and  not 
with  any  amphibolite  known  as  an  independent  rock  in  the  region.  The 
other  is  a  fine-grained  granite  or  eurite,  like  that  so  common  in  the  veins 
that  cut  the  rock  abundantly.  Both  these  rocks  seem  to  have  separated 
from  the  magma,  to  have  been  accumulated  here  in  unusual  amount,  and 
to  have  been  roimded  by  resorption  according  to  the  methods  discussed 
in  the  articles  cited  above. 

The  locality  where  these  forms  are  found  is  at  the  upper  dam  at  West 
Brook,  on  the  north  line  of  Hatfield. 

A  third  most  interesting  variety  of  the  syenite  is  described  as  follows : 

Augitic  syenite. — The  presence  of  hornblende  in  this  variety  and  the  absence  of 
mica  have  led  me  to  call  it  augitic  syenite  rather  than  augitic  granite,  although  in 
position  it  is  associated  with  granite.  There  are  two  varieties.  The  first  is  com- 
posed of  black  hornblende,  greenish  augite,  and  yellowish  feldspar,  all  the  ingre- 
dients except  the  feldspar  exhibiting  a  very  distinct  and  lively  crystallization.  This 
variety  occurs  in  the  northern  part  of  Belchertown.  The  other  variety,  which  I 
have  found  only  in  bowlders  in  Amherst,  consists  of  augite  and  feldspar,  the  former 
being  so  arranged  in  the  latter  as  to  present  the  appearance  of  letters.^ 

H.e  insists,  further,  on  the  low  level  occupied  by  the  syenite  in  the 
valley  and  upon  its  columnar  structure,  and  describes  in  considerable 
detail  the  segregated  veins  which  occur  so  abundantly.     He  presents  a 

'  See,  for  several  citations,  R.  Pohlman,  Emschliisse  von  Granit  in  Lamprophyr :  Neues  Jahrbuch 
fiir  Mineral,  etc.,  1888,  II,  p.  87,  and  note  on  page  92. 

■■'This  is  a  contact  modification  of  the  amphibolite  bordering  the  granite  and  is  described  on 
p.  243. 


334  GEOLOGY  OF  OLD  HAMPSHIEB  COUNTY,  MASS. 

discussion  of  these  last  in  the  Report  of  1833,  suppressed  in  that  of  1841, 
which,  as  he  develops  it,  has  some  resemblance  to  the  theory  of  "schlie- 
rengange,"  as  developed  by  E.  Reyer. 

The  greater  part  of  the  veins  in  our  syenite  consists  of  material  foreign  to  the 
nature  of  the  rock  and  introduced  subsequently  to  its  original  production.  I  do  not 
say  subsequently  to  its  consolidation,  for  it  has  appeared  to  me  possible  that  while  a 
molten  mass  of  rock — say  syenite — was  in  an  incipient  state  of  refrigeration  matter  of 
a  similar  kind  still  more  intensely  heated  might  have  been  injected  into  it,  so  as  to 
form  veins. 

Other  veins  associated  with  faulting  he  refers  to  the  filling  of  fissures 
formed  in  the  solid  rock. 

Under  the  head  "Mineral  contents"  he  refers  a  mineral  crystallizing  in 
four-sided  ^Drisms  to  rutile.  It  is  allanite.  He  mentions  quartz  crystals 
and  "gashed  quai'tz,"  quartz  "full  of  thin  fissures,  as  if  made  by  random 
cuts  of  a  knife,"  and  explains  it  as  due  to  the  growth  of  quartz  about  some 
mineral  now  removed.  This  mineral  was  doubtless  barite.  The  minerals 
of  the  Hatfield  baryta  mine  are  also  enumerated.  Under  the  head  "Theo- 
retical conclusions"  the  hypothesis  is  advanced  that  "the  syenite  Avas  formed 
by  the  melting  down  of  the  hornblende-schist,"  and  in  proof  of  this  he  pre- 
sents a  rude  diagram  of  the  state  of  things  at  the  north  end  of  the  syenite  in 
Whately.  In  this  diagram  the  syenite  is  represented  as  being  succeeded  to 
the  north  by  hornblende-schist,  the  two  being  in  contact  and  the  bedding  of 
the  schist  being  continued  in  a  rude  stratification  of  the  syenite.  He  adduces 
also  the  fact  that  the  hornblende-schist  on  its  western  border,  a  mile  north 
of  the  syenite,  is  massive,  columnar,  and  feldspathic,  and  theorizes  that  there 
was  here  heat  "sufficient  for  the  production  of  feldspar,  but  not  for  its  crys- 
tallization;" that  with  a  greater  degree  of  heat  syenite  would  have  been 
produced;  with  a  still  greater,  the  production  of  hornblende  would  have 
been  impossible  and  granite  would  have  resulted. 

The  diagram  and  description  of  the  relations  of  the  syenite  and  the 
hornblende-schist  in  Whately  are  based  upon  a  serious  error  of  observation. 

The  hornblende-schist  Avhich  outcrops  in  great  force  north  and  south 
of  the  south  line  of  Whately  is  toward  the  north  separated  by  argillite  from 
the  broad  band  of  hornblende-granite  with  which  the  diagram  connects  it. 
C.  H.  Hitchcock,  in  1871,^  classed  the  rock  as  a  Laurentian  gneiss. 

'Explanation  of  geological  map  of  United  States,  in  Waiting's  Atlas  of  Massachusetts. 


TONALITE.  ,  335 

It  is  put  iis  iui  "exolic  Montalbmi  granite"  on  the  "centennial  map"  of 
W.  0.  Crosby,'- because  it  is  micaceous  as  well  as  liornblendic  and  because 
it  contains  a  center  of  true  g-ranite  (according  to  President  Hitchcock's  map 
of  1844)  in  the  southwest  comer  of  Belcliertown — a  groundless  argument, 
since  the  granite  in  (juestion  is  simply  a  great  pegmatite  dike  which  cuts 
the  tonalite.  • 

DISTRIBUTION. 

On  the  west  side  of  the  river  the  rock  commences  in  "Whately,  a  short 
distance  southwest  of  the  village,  where  it  is  seen  in  contact  with  the 
Leyden  argillite,  producing  a  marked  contact  metamorphism  (p.  205),  and 
runs  south  in  a  long,  bare  ridge  ("The  Rocks"),  hke  a  great  dike,  into 
Northampton,  where  it  ends  in  Elizabeth  Rock.  It  is  6  miles  long  and  2 
miles  wide.  East,  west,  and  south  broad  areas  of  sands  and  sandstones 
separate  it  from  its  neighbors.  To  the  west  of  its  south  end  it  grades 
into  a  great  area  of  biotite-granite  identical  with  itself  except  in  the  absence 
of  hornblende. 

On  the  east  side  of  the  river  a  great  squarish  mass  occupies  the  south- 
west portion  of  Belchertown,  extending  into  Granby  and  Ludlow,  its  con- 
tacts, unfortunately,  greatly  obscured  by  the  heavy  post-Glacial  sands.  It 
is  a  great  batholite  and  in  many  places  strong  contact  metamorphism  can 
be  observed  at  its  borders  and  in  broad  sheets  of  schists  that  float  out  in 
the  center  of  the  great  mass.     (See  p.  243.) 

North  from  the  northwest  corner  of  the  area  of  tonalite  across  Belcher- 
town and  Pelham,  and  so  on  north  in  the  foothills,  is  a  line  of  oiitcrops 
of  much  crushed  rock  which  seem  at  times  like  amphibolite  shot  through 
by  many  small  aplite  veins  and  at  times  like  the  tonalite.  The  Shays  flint 
is  a  peculiar  facies  of  this  rock  which  resembles  a  petrosilex.  As  it  runs 
along  the  western  border  of  Mount  Hygeia  it  is  quite  gneissoid,  but  appears 
.  in  Leverett  in  typical  development  as  a  beautiful  dark-green  granitoid  rock 
shot  through  with  epidote  veins.  Also,  going  north  from  the  northeast  cor- 
ner of  the  Belchertown  mass  along  the  corresponding  eastern  foothills  of 
the  next  valley  to  the  east,  across  Prescott  and  New  Salem,  a  similar  line 
of  tonalite  outcrops  occurs,  ending  with  the  great  block  of  diorite  on  the 
north  line  of  Prescott.    These  are  both  lines  of  strong  faulting  and  crushing. 


'  Report  on  a  Geological  Map  of  Massachusetts,  p.  31. 


336 


GEOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 


ANALYSES    OF    TONALITE. 


Analyses  of  the  tonalite  were  made  in  the  laboratory  of  Amherst 
College  (1)  by  William  Orr,  jr.,  and  (2)  by  F.  H.  Fitts.  A  third  (3)  was 
made  by  L.  Gr.  Eakins,  of  the  United  States  Geological  Survey: 

Analyses  of  tonalite. 


1. 

2. 

3. 

SiOa 

56.69 

.62 

15.48 

6.22 

56.18 
1.60 

1    22.79 

55.51 

.91 

.     16.51 

I      1.68 

4.57 

.11 

.02 

6.73 

6.73 

3.19 

2.46 

1.53 

.17 

TiOa 

A1,0,              

Fe.O               

FeO 

MnO         

BaO          

CaO          

7.59 
6.53 
3.41 
3.43 

6.49 
6.53 
3.40 
3.27 

MgO    

NaO 

K„0                      

H2O 

PiOj 

99.97 

100.  26 

100. 12 

Analyses  1  and  2  were  made  from  the  same  hand  specimen  of  the 
slightly  amethystine,  fresh,  medium-grained  tonalite,  which  showed  with 
the  lens  dark,  bronzy  diallage,  and  bright-green  hornblende  and  amethys- 
tine quartz.  The  specimen  came  from  just  north  of  Three  Rivers,  in 
Belchertown.  Analysis  3  was  made  from  the  beautiful  epidotic-veined  rock 
from  the  crossroads  east  of  South  Leverett,  described  on  page  339,  which 
was  more  altered  than  the  others. 


PETROGRAPHICAL    DESCRIPTION. 

MacroscopicaL — The  rock  is  a  wholly  granitoid,  medium-  to  fine-grained 
and  very  even-grained  mixture  of  quartz,  orthoclase  (*?),  plagioclase,  biotite, 
and  hornblende,  the  latter  being  at  times  replaced  by  a  dark-bronze  dial- 
lage in  the  Belchertown  area,  a  mineral  which  occurs  very  rarely  in  the 
Hatfield  region.  The  passage  of  diallage  into  hornblende  can  be  well 
observed,  and  reasons  will  be  given  below  for  the  assumption  that  the  rock 


TONALITE.  337 

was  orig'hiiiUy  erupted  as  a  diallage-biotite-gabbro.  It  becomes  aplianitic 
in  places,  but  is  uever  porphyritic  or  pegmatitic.  It  is  a  tough,  compact 
rock  not  easily  disintegrated,  but  weathering-  white.  It  is  light-gray,  often 
greenish,  the  two  colored  constituents  rarely  predominating,  so  as  to  give 
it  a  dark-gi-ay  shade,  but  often  weathering  so  as  to  give  it  a  greenish  tint. 
In  other  cases  the  feldspar  weathers  red,  and  it  always  has  a  somewhat 
compact  appearance,  the  cleavage  hardly  appearing. 

In  the  south  of  Belchertown  a  beautiful  variety  occurs  abundantly. 
The  quartz  is  amethystine,  the  diallage  dark-bronze  colored,  the  hornblende 
bright-green.  Very  generally  the  decomposition  of  the  hornblende  has 
furnished  a  large  quantity  of  chlorite,  which  then  gives  a  green  shade  to  the 
rock. 

Microscopical. — A  description  of  the  quartz-gabbro  from  South  Bel- 
chertown specimens  will  be  given  first,  as  the  least  altered  form  of  the  rock. 
In  thin  sections  the  quartz  shows  fluid  inclusions  with  moving  bubbles. 
Long,  fine,  rigidly  straight,  opaque  needles  of  rutile  occur  in  great  abun- 
dance, and  are  often  divided  into  many  widely  and  regularly  separated  parts, 
all  perfectly  aligned.  The  feldspar  is  nearly  all  triclinic,  with  extinction 
of  adjacent  bands  at  12°  to  14°.  Ortlioclase  could  not  be  proved  to  be 
present.  The  diallage  is  in  separate,  quite  well-formed  crystals  of  pale- 
green  color,  but  so  loaded  with  the  customary  red  and  black  inclusions  as 
to  give  it  a  deep-brown  color.  In  sections  parallel  to  oo  P  co  (100)  these 
are,  in  abundance,  shape,  and  arrangement,  exceedingly  like  the  Labrador 
hypersthene,  and  the  vertical  striation  is  clearly  developed.  In  sections 
parallel  to  oo  P  co  (010)  the  red  plates  are  not  nearly  so  much  shortened 
parallel  to  the  vertical  axis  as  in  the  hypersthene,  and  are  so  abundant 
as  nearly  to  obscure  the  green  color  of  the  diallage. 

In  one  regular  octagonal  basal  section,  while  the  diallage  cleavage  is 
finely  developed,  and  a  cleavage  less  perfect  and  at  right  angles  thereto 
is  clearly  seen,  the  prismatic  cleavage  is  entirely  wanting.  In  another 
twinned  very  clearly  after  the  common  pyroxene  law,  on  oo  P  co  (100), 
all  the  tln-ee  cleavages  are  developed,  the  co  P  co  (100)  cleavage  being 
much  the  best.  The  freshest  of  these  crystals  are  surrounded  by  a  narrow 
zone  of  gi-een,  rounded  plates  of  hornblende,  in  which  the  black  inclusions 
remain,  but  the  red  do  not. 

MON  XXIX 22 


338  GEOLOG-T  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 

In  other  crystals  this  change  has  proceeded  in  every  degree  until  the 
crystal  becomes  wholly  changed  to  a  fibrous  hornblende  (uralite),  in  which 
the  black  inclusions  of  the  diallage  still  remain,  and  indeed  appear  often  to 
be  considerably  increased  at  the  expense,  it  would  seem,  either  of  the  red 
inclusions  or  of  the  diallage  itself,  and  to  possess  in  the  hornblende  a  very 
distinct  zonal  arrangement.  Furthermore,  the  hornblende  itself  is  in  most 
cases  changed  more  or  less  into  an  aggregate  of  rounded  green  scales  of 
chlorite,  but  sliglitly  dichroic,  which  has  in  many  cases  eaten  into  the 
center  of  the  hornblende  in  great  patches,  in  others  has  surrounded  it  in 
a  regular  layer. 

Finally,  very  peculiar  and  delicate  plumose  aggregations  of  elongate, 
round-ended  scales  of  biotite  are  gathered  in  tufts  at  spots  along  the  outside 
of  the  chlorite  and  attached  to  it,  or  a  group  of  such  tufts  radiates  from  a 
center  in  which,  in  each  case,  remains  of  the  green  chlorite  scales  appear. 
The  whole  arrangement  suggests  very  strongly  the  derivation  of  the  biotite 
from  the  chloritic  mineral  parallel  with  the  decomposition  of  the  feldspar. 
In  another  case  a  flat  patch  of  the  green  chlorite  scales  seems  to  change 
gradually  into  a  mass  of  brown  biotite  scales,  some  of  the  small  plates 
having  the  green  color  and  weak  pleochroism  of  chlorite  at  one  end  and  the 
brown  color  and  strong  pleochroism  of  biotite  at  the  other,  and  these  latter 
pass  into  a  single  large  biotite  crystal,  so  that  one  can  hardly  avoid  con- 
cluding that  the  biotite  has  been  derived,  in  part  at  least,  from  the  diallage 
through  the  hornblende  and  chlorite  stages.  The  earliest  stage  may,  of 
course,  have  been  with  diallage  surrounded  by  biotite,  and  the  change  to 
chlorite  may  have  proceeded  both  ways  from  the  boundary. 

Many  slides  cut  from  various  parts  of  the  area  show  no  remains  of  the 
diallage,  but  only  the  fibrous  hornblende  containing  the  zonally  arranged 
black  inclusions,  and  having  chlorite  and  biotite  arranged  with  regard  to  it 
exactly  as  in  the  slides  where  the  diallage  is  present.  We  may  thus  con- 
clude that  the  diallage  was  once  widely  and  abundantly  present  in  the  rock. 

Apatite  occurs  in  exceptionally  large  crystals  in  the  hornblende. 

To  the  above  description  of  the  pyroxenic  varieties  are  added  some 
special  notes  upon  the  commoner  and  more  altered  biotite  amphibole  granite, 
or  tonalite,  and  upon  one  or  two  rare  varieties. 

The  quartz  is  everywhere  distinctly  subordinate  to  the  feldspar,  and 
molds  the  latter.     At  Elizabeth  Rock,  in  the  north  of  Northampton,  it  is 


TONALITE.  339 

ver)'  lull  of  ciu'ities  with  moving-  bubbles,  many  of  the  cavities  containing 
water  and  carbon  dioxide  and  a  moving  bubble  of  the  latter. 

The  feldspar  is  uniformly  very  much  more  decomposed  than  the  appear- 
ance of  the  rock  would  lead  one  to  suspect.  Sometimes  the  change  is  into 
kaolin,  sometimes  into  muscovite.  The  change  is  always  central,  and  at 
times  a  sharply  defined  diamond-shaped  area  of  change  occurs  in  a  square 
crvstal.  This  change  is  so  general  that  it  can  only  be  determined  that  the 
feldspar  is  for  the  most  part  triclinic,  with  extinction  at  small  angles. 

The  hornblende  is  often  twinned,  and  extinguishes  at  high  angle — 
19°-21°. 

Epidote,  in  minute  groixps  in  the  chlorite,  and  titanite  are  abundant  in 
the  Whately  bed. 

Allanite  is  frequent,  especially  in  the  Hatfield  bed,  in  crystals  visible  to 
the  eye,  and  surrounded  by  the  peculiar  radiate  puckering  or  splintery 
fracture  common  around  this  mineral.  Under  the  microscope  it  is  at  times 
suiTOunded  by  epidote. 

In  the  Hatfield  mass  the  biotite  is  subordinate  and  the  rock  agrees 
exactly  with  the  tonalite  of  the  Tyrol.  In  Belchertown  it  is  more  biotitic. 
In  the  latter  area,  in  the  region  around  Three  Rivers,  the  quartz  is  ame- 
thystine and  contrasts  beautifully  with  the  green  diallage.  This  variety 
shows  under  the  microscope  a  beautiful  granophyre  structure.  Farther  east, 
in  South  Belchertown,  large  bowlders  on  the  railroad  show  a  coarsely  por- 
phyritic  development  of  the  biotite,  each  of  the  large  scales  being  surrounded 
by  a  white  border,  and  the  quartz  in  this  variety  is  violet,  like  the  pre-Cam- 
brian  gneiss  in  the  western  portion  of  the  State. 

THE  CRUSHING  AND  ALTERATION  OF  THE  TONALITE  ALONG  THE  PELHAM 

FAULT. 

The  outcrops  of  the  tonalite  which  appear  in  the  line  of  the  great  fault 
at  the  foot  of  the  eastern  plateau  from  Belchertown  to  Leverett  are  greatly 
altered  by  the  movements  which  have  taken  place  along  that  line.  Follow- 
ing the  road  west  from  South  Leverett  to  the  point  where  an  unused  road 
goes  east  to  the  old  cemetery,  one  finds  a  large  outcrop  of  a  beautiful  dark- 
green  chloritic  tonalite,  in  which  the  reddish  feldspar  contrasts  finely  with 
the  dark  hornblende,  and  the  contrast  is  heightened  by  a  network  of  fine, 


840  GEOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 

dark-greeu,  epidotic  quartz  veins.  Between  this  and  the  Monson  gneiss  to 
the  east  the  lower  coarse  mica-schist  crops  out.  In  thin  section  the  feld- 
sj)ars  are  largely  triclinic,  and  the  constituents  are  larger  and  clearer  than 
elsewhere  in  the  series,  but  much  crushed.  The  epidotes  are  especially- 
large  and  well  crystallized.  Titanite,  which  is  not  wanting  in  the  other 
sections,  is  especially  abundant  here.  An  analysis  of  this  rock  is  given  on 
page  336. 

The  band  is  covered  by  heavy  sands  across  Shutesbury,  but  reappears 
at  "Mount  Boreas,"  above  Pratts  Corner,  and  a  mile  east  of  the  pond  a  mile 
south  of  South  Leverett.  The  western  half  of  the  hill  is  made  up  of  the 
whetstone-schist,  so  crushed  that  dip  and  strike  can  be  determined  with 
difficulty,  and  the  eastern  slope  by  an  equally  crushed  quartzose  amphibolite, 
while  below,  by  the  stream,  is  a  tonalite  which  is  somewhat  gneissoid,  and 
is  doubtless  the  continuation  of  the  ornate  rock  mentioned  above,  though 
from  the  greater  amount  and  the  colorlessness  of  the  quartz  and  feldspar  it 
has  not  its  attractive  appearance.  This  rock  continues  across  Pelham  in  a 
narrow  band  resting  in  the  foothills  against  the  older  gneiss  and  separated 
by  a  broad  area  of  sands  from  the  feldspathic  mica-schist  of  the  center  of 
Amherst.  It  is  a  highly  hornblendic  granitoid  gneiss,  much  intersected  by 
epidotic  quartz  veins  and  often  very  chloritic. 

The  large  mass  of  leek-green  hornstone  known  locally  as  Shay's  flint,-^ 
from  the  tradition  that  it  was  used  for  flints  during  Shay's  rebellion,  was 
found  on  Amethyst  Brook,  in  Pelham,  just  where  this  band  crosses  it.  It 
was  a  bowlder,  and  its  oi'igin  Avas  unknown.  Some  years  ago  I  found 
the  same  material  in  place  where  the  band  of  hornblende -gneiss  (altered 
tonalite)  crosses  the  south  line  of  Pelham.  It  forms  beds  in  the  latter 
sometimes  as  much  as  20  feet  thick,  and  at  times  crosses  the  bedding.  It 
is  a  cryptocrystalline  quartz,  colored  green  by  chlorite  derived  from  the 
decomposing  hornblende  of  the  granite,  passing  from  green  to  flesh  color 
and  weathering  white  and  grading  into  ordinary  gneiss,  and  it  is  a  result 
of  the  thorough  crushing  and  silicification  to  which  the  rock  has  been  sub- 
jected. The  veins  colored  by  epidote  are  not  essentially  different  from 
these,  though  they  do  not  reach  such  large  dimensions,  and  where  the 
fissure  is  not  entirely  filled  they  show  beautiful  plane,  polished  surfaces  of 

'  For  tlie  history  of  the  rock,  which  has  been  called  plasma,  prase,  and  green  hornstone,  see 
under  "Quartz,"  in  A  mineralogical  lexicon:  Bull.  U.  S.  Geol.  Survey  No.  126,  1895,  p.  135. 


TONALITE.  341 

the  chalcedonic  quartz,  colored  a  lig-lit  i)istachio-green  by  epidote.  These 
surfaces  are  not  "slickeusides,"  but  are  as  if  varnished,  and  are  caused  by 
the  crystallization  of  the  fine-grained  material.  They  are  analogous  to  the 
smooth  surface  of  botryoidal  chalcedony  or  limonite. 

A  similar  petrosiliceous  variety  occurs  in  Whately — a  pale  leek-green, 
subgranular  mass,  of  hornstone-like  appearance,  with  a  few  crushed  mus- 
covite  plates.  It  shows  no  biotite  or  quartz.  The  luster  is  generally  dull, 
but  here  and  there  the  sheen  of  a  feldspar  cleavage  appears,  and  this 
always  shows  tri  clinic  striation.  It  appears  at  the  Hatfield  lead  mine 
in  thin  layers  on  fissures.  (XVIII,  No.  57,  in  Massachusetts  Survey 
Collection.) 

PETEOaRAPHICAL  DESCRIPTION  OF  THE  ALTERED  TONALITES. 

''  Shay's  flint,"  Pelliam,  the  typical  rock.  Under  the  microscope  this 
shows  a  regularly  mottled  aggregate  polarization  which  has  some  resem- 
blance to  clastic  structure,  but  more  to  that  of  agate  or  chemically  deposited 
quartz;  and  as  it  resembles  exactly  the  purer  parts  and  the  veins  of  the 
same  hornstone  from  Pelham,  in  situ,  I  have  no  doubt  that  it  is  chemically 
deposited  silica,  rendered  impure  by  kaolin  and  a  little  green  chlorite.  It 
is  in  large  part  apolar,  and  therefore  opal. 

Tonalite,  Pelham,  west  line  north  of  S.  Jewett's.  Dark  hornblende 
abundant,  feldspar  flesh-colored.  In  section  very  feldspathic,  the  feldspars 
(mostly  triclinic)  greatly  kaolinized;  all  constituents  reach  the  extreme  of 
crushing — the  hornblendes  opened  along  cleavage  planes;  the  feldspars 
crushed  and  parts  moved;  the  twin  striation  greatly  twisted,  and  the 
undulatory  extinction  greatly  obscuring  the  twinning;  hornblende  shows 
jc  =  green,  lj  =  olive,  a  =  yellow;  x;=t)(>a. 

Green  hornstone,  like  "Shay's  flint,"  from  locality  where  first  found 
by  me  in  place  in  Pelham,  at  S.  Jewett's.  This  is  a  quartz  mass,  filled  with 
scales  like  kaolin,  which  are  opaque  by  transmitted  and  white  by  reflected 
light,  and  permeated  by  veins  which  have  the  same  scattered  scales.  It 
resembles  exactly,  both  with  and  without  polarized  light,  the  true  "Shay's 
flint."  Some  slides  show  a  beautiful  microbrecciation  from  crushing.  They 
contain  magnetite  and  a  little  green  chlorite.  Under  the  polarizer  there 
appear  now  and  then  larger,  rounded,  transparent  grains,  which  may  be 


342  GEOLOGY  OP  OLD  HAMPSHIEE  COUNTY,  MASS. 

the  original  quartz  grains.     The  structure  seems,  however,  in  general  much 
more  like  that  of  agate.     It  contains  much  opal. 

Pelham,  south  line,  40  rods  east  of  western  road.  A  coarse,  schistose, 
hornblende-gneiss;  coarse,  wavy  cleavage  siirfaces  of  hornblende  make  up 
foliation  faces,  luster-mottled  by  roinided  grains  of  fresh  white  feldspar,  in 
which  cleavage  is  feebly  developed.  In  section  the  hornblende  is  in  large, 
fresh  plates,  exactly  like  the  few  developed  in  the  section  last  described ;  it 
shows  deep  colors,  weak  pleochroism,  and  is  much  cracked  and  twisted  by 
pressure.  The  feldspar  is  very  fresh,  and  shows  a  great  variety  of  triclinic 
striation — very  broad  to  very  narrow  bands  with  perfectly  parallel  sides, 
and  tapering,  interrupted,  and  offset  bands ;  also  bands  wavy  and  contorted 
by  pressure  and  associated  undulatory  extinction.  In  one  crystal,  cut  at 
right  angles  to  0  P  (001),  all  the  laws  of  twinning  are  beautifully  developed. 

Belchertown,  northwest  corner,  40  rods  east  of  R.  Thayer's.  A  green 
granitoid  rock  of  medium  grain,  mottled  with  flesh-red  from  decomposed 
feldspar;  distinctly  foliated.  In  section  broad  hornblendes  much  crushed, 
feldspars  crushed,  showing  undulatory  extinction,  much  kaolinized,  many 
triclinic,  with  small  extinction  angle;  much  chlorite  and  epidote,  the  latter 
often  with  distinct  crystal  faces  externally,  but  with  rounded  zonal  struc- 
ture internally,  the  spherical  center  extinguishing  first  and  then  successive 
zones  in  order  to  the  surface,  with  revolution  of  17°. 

A  little  farther  south,  on  same  band,  north  of  house  of  A.  Groodale,  the 
wholly  crushed  and  altered  rock  is  hornstone-like,  with  a  dull  mottling  of 
greenish  and  flesh  color.  In  section  the  bisilicate  is  almost  wholly  removed, 
and  the  quartz-plagioclase  mass  is  wholly  crushed,  with  wavy  extinction 
and  twisted  twin  laminse.  This  is  the  south  end  of  the  "Shay's  flint"  band. 
Followed  40  rods  east,  its  contact  on  Pelham  gneiss  is  seen.  There  is  a 
hornblende-biotite-gneiss  for  a  rod  at  the  contact,  and  the  Pelham  gneiss 
is  full  of  granite  dikes. 

DIOBITE. 

North  Prescott  and  New  Salem. — A  great  oval  area  of  diorite,  3  miles 
long  from  north  to  south  and  about  a  mile  wide,  lies  across  the  line  sepa- 
rating the  above  towns.  It  is  a  resistant  rock,  and  makes  the  whole  of 
Packards  Mountain  in  the  latter  town.  It  is  surrounded  on  all  sides  by 
the  gneissoid  quartzites,  which  dip  uniformly  to  the  west,  undisturbed  by 
the  intrusive  rock.     On  all  sides  as  one  approaches  the  mass  the  quartzite 


DIORITE.  343 

grows  more  gneissoid  fi'ora  contact  iuflvieiice,  but  this  is  not  marked.  The 
rock  is  normally  dark-gray  or  nearly  black,  with  a  shade  of  brown,  and 
seems  at  first  sight  to  be  fine-grained;  but  when  held  to  the  light  it  is  seen 
to  be  made  up  of  squarish  surfaces,  from  a  half  to  three-fourths  of  an  inch 
across,  of  jet-black  to  dark-green  hornblende,  very  beautifully  luster- 
mottled  by  fresh,  white,  striate,  broad  lath-shaped  plagioclases,  and  show- 
ing rarely  a  grain  of  quartz,  garnet,  or  a  black  ore. 

It  is  in  places  bedded,  and  on  the  west,  in  the  hill  above  Cooleyville, 
one  ti'aces  the  amphibolite  into  immediate  proximity  to  the  diorite,  where 
it  is  thickened  imusually,  is  massive,  and  greatly  resembles  the  diorite. 
It  may  be  a  compacted  and  altered  ash  bed,  associated  with  the  eruptive 
rock.  In  the  southwest  portion  of  the  mass,  near  A.  Pierce's,  in  Prescott 
Hollow,  the  diorite  is  a  coarse,  white,  feldspathic,  slightly  saussuritic  rock, 
with  only  small,  distant  patches  of  a  dark  silicate,  now  changed  to  a  mixture 
of  actinolite  and  biotite. 

The  freshest  material  for  microscopical  study  was  obtained  from  a 
great  bowlder  on  the  north  side  of  the  road  west  from  Prescott  Center,  near 
the  last  house  in  the  village.  (See  PI.  Ill,  fig.  3.)  It  presents  a  very 
attractive  appearance  under  the  microscope.  A  portion  of  a  single  horn- 
blende crystal  occupies  the  whole  field,  notched  by  the  regular  crystals  of 
feldspar,  which  run  in  every  direction.  It  shows  a  maximum  extinction 
angle  of  22°,  and  is  therefore  near  labradorite.  It  is  quite  fresh,  and  full 
of  acicular  needles. 

The  hornblende  is  deep-green,  extinction  20°,  with  slight  pleochroism, 
c=ii  <a;  jc  =  bkie,  I»  =  olive-green,  a  =  yellow. 

It  is  dusted  full  of  a  very  fine  black  powder,  in  bands  more  or  less 
dense,  parallel  to  the  cleavage,  rendering  wholly  opaque  the  central  parts 
of  the  lobes,  into  which  the  crystal  is  divided  by  the  feldspars,  while  it 
shades  off  toward  the  border,  where  it  is  still  more  densely  accumulated 
in  a  broad  band  bordering  the  feldspars.  In  places  the  central  portions 
of  the  lobes  are  crowded  by  red-brown  scales,  placed  largely  at  right 
angles  to  the  bedding  and  resembling  those  found  in  bronzite.  Cleavage 
pieces  of  the  hornblende  measured  with  the  reflecting  goniometer  gave 
124°  30'.  Rarely  a  large  pale-green  pyroxene  appears,  with  a  border 
of  hornblende ;  and  menaccanite  and  red-brown  rutile,  with  fine  leucoxene 
borders,  are  present. 


344       GEOLOGY  OF  OLD  HAMPSHIEB  COUNTY,  MASS. 

In  other  slides,  from  near  H.  Winter's,  the  rock  is  greatly  decomposed, 
the  feldspars  are  mostly  kaolinized,  the  hornblende  is  broken  up  into  a 
network  of  actinolite  and  biotite,  and  only  disconnected  patches  of  the 
black  opacite  remain.  Secondary  quartz  and  calcite  appear.  One  feld- 
spar was  shown,  by  the  position  of  the  optical  axes,  to  be  orthoclase. 
Here,  and  in  sections  from  the  south  border,  the  plagioclase  shows  fine 
undulatory  extinction.  In  the  coarse  white  variety  from  A.  Pierce's  the 
feldspar  is  full  of  muscovite  and  the  dark  silicate  is  changed  to  an  actino- 
lite, with  very  strong  transverse  fissures.  One  feldspar,  cut  parallel  to 
M  (oo  P  c»),  showed  extinction  — 35°-36^,  with  edge  P  M,  indicating 
anorthite. 

In  fissures  in  the  diorite  beside  the  road  near  the  old  cemetery  a  large 
quantity  of  pure-white  radiated  prehnite  occurred.  It  was  proved,  optic- 
ally and  by  measurements  under  the  microscope  as  well  as  by  blowpipe 
tests,  to  belong  to  this  species.^ 

Leverett  Center. — North  and  south  of  the  road  east  from  this  place  to 
the  point  where  this  road  turns  south  are  outcrops  of  a  massive  rock  which, 
although  greatly  decomposed,  gives  every  indication  of  having  been  a 
diorite  of  the  same  type  as  that  last  described.  With  the  lens  the  rock 
is  seen  to  be  com^josed  of  saussuritic  feldspar  and  coarsely  cleavable 
black  hornblende,  arranged  with  the  texture  of  a  gabbro.  The  feldspar  is 
often  included  in  separate  grains  in  the  hornblende,  or  rarely  in  pyroxene. 
Its  feldspars  are  generally  wholly  kaolinized,  but  their  shape  and  arrange- 
ment are  exactly  those  of  the  Prescott  rock.  They  show  extinction  of  12° 
to  25°.  The  intervening  hornblende  is  mostly  changed  into  a  matted 
mass  of  actinolite  needles  of  weak  pleochroism,  or  changed  to  serpentine, 
but  does  at  times  polarize  together  over  a  considerable  area,  and  shows 
large  patches  of  the  black  opacite,  exactly  as  does  the  altered  portion  of 
the  Prescott  diorite.  Masses  of  menaccanite  surrounded  by  leucoxene 
are  especially  abundant,  and  the  apatites  are  unusually  large,  0.12"°'  across 
by  0.37 """  long.  The  rock  presents  both  the  varieties  described  under 
the  Prescott  rock.  Owing  to  the  drift  covering,  its  extent  and  relations 
can  not  be  well  made  out. 

'  See  under  "Prelimte,"  in  A  mineralogical  lexicon:  Bull.  U.  S.  Geol.  Survey  No.  126,  1895. 


DIOllITE  AND  GAENET-BIOTITE-NOllITE. 


345 


All  iuiiilysis  of  this  rock  from  opposite  a  house  of  gothic  architecture 
east  of  Leverett  is  given  below.     It  was  made  liy  Mr.  L.  G.  Eakius: 

Analt/ais  of  diorite  from  Leverett. 


A  wholly  exceptional  band  of  diorite  occurs  at  the  top  of  the  whetstone 
in  the  hill  west  of  A.  Adams's,  in  the  south  of  Leverett,  and  is  continued  to 
the  west  of  the  north  end  of  the  "  Flat  Hills  "  road  in  the  northeast  corner 
of  Amherst.  It  is  here,  in  a  bed  325  feet  wide,  a  dark,  tough,  massive 
diorite,  much  decomposed  and  associated  with  siliceous  limestone. 

Some  of  the  amphibolites  described  in  Chapter  X  as  of  doubtful  origin 
may  be  altered  diabases  or  diorites,  and  thus  belong  here. 

GARlVET-BIOTITE-lSrOIMTE. 

The  rock  appears  in  a  single  isolated  outcrop  in  the  roadside  near 
Gr.  Peffer's  house,  in  the  village  of  Parksville,  in  Brimfield.  It  is  a  fresh, 
dark  olive-green  rock  of  granitic  texture  and  slightly  above  medium  grain. 
Large  grains  of  deep-red  garnet  are  quite  abundant,  and  here  and  there 
a  group  of  black  biotite  scales  appears,  often  crumpled.  Many  shining 
cleavage  surfaces  of  the  feldspar  occur  which  do  not  show  striation,  though 
the  microscope  shows  all  or  nearly  all  of  these  grains  to  be  multiple- 
twinned. 

The  microscope  shows  the  field  to  be  almost  wholly  made  up  of  a  coarse, 
entirely  fresh  mosaic  of  xenomorphic  and  equidimensional  feldspar,  which 
has  all  the  optical  properties  of  a  labradorite  (Ali  Auj),  with  broad  twinning 


346       GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

bands  sometimes  wanting  or  extending  only  a  little  way  in,  as  if  the  rock 
were  but  slightly  affected  by  pressure.  It  is  sometimes  crowded  with  fine 
black  needles  ^larallel  to  the  axis  c  and  with  swarms  of  brightly  polarizing 
grains. 

The  garnet  is  fresh,  without  inclusions  or  polarization,  and  partly  idio- 
morphic. 

The  biotite  is  in  aggregates  of  long,  brown  blades,  with  the  usual  very 
strong  absorption,  sometimes  accompanied  by  fine  radiating  wisps  of  mus- 
covite.  It  is  usually  also  associated  with  hypersthene,  which  is  in  stout 
prisms,  often  showing  the  flat  end  faces.  It  is  pale-green,  without  inclusions, 
and  shows,  jC  =  ulti-amarine,  \s  =  reddish  yellow,  a  =  deep  salmon  color. 
Some  crystals  are  altered  at  one  end  into  a  green,  negative,  micaceous 
mineral  and  change  at  the  other  into  a  brown-red  serpentine. 

The  dark-colored  constituents  form  a  very  small  portion  of  the  rock. 
The  outlines  of  this  occm-rence  can  not  be  made  out  as  it  rises  through  the 
sands  of  a  post-Glacial  lake.  It  is  one  of  a  series  of  isolated  stocks  of 
highly  basic  rocks,  all  very  fresh  and  interesting  for  microscopical  study, 
which  run  noi'th  near  the  eastern  border  of  the  map,  but  mostly  outside  its 
limits  in  Worcester  County,  iiacluding  picrite,  olivine-gabbro,  and  wehrlite. 

CORTLAISTDITB. 

A  single  great  mass  of  a  brownish-black  rock  closely  comparable  to 
one  of  the  commonest  types  of  the  Cortland  series  occurs  in  the  center  of 
the  great  tonalite  area  in  the  southwest  corner  of  Belchertown,  near  D. 
Griffin's.  It  is  a  hornblende-pyroxene-biotite-peridotite.  The  most  strik- 
ing peculiarity  of  the  rock  is  that  at  times  it  breaks  up  into  angular  blocks 
with  so  great  regularity  that  the  fragments  form  rude  rhombic  dodecahedra 
with  faces  about  2  inches  across,  and  the  surfaces  of  these  blocks  are  cov- 
ered with  a  thin  layer  of  brown-red  biotite  scales,  approximately  parallel 
and  luster-mottled  by  grains  of  an  emerald-green  pyroxene.  This  pecu- 
liarity is  still  more  strikingly  illustrated  in  the  Cortland  rock,  and  the 
structure  seems  to  replace  a  primary  one,  as  in  the  deeper  and  fresher  por- 
tions of  the  rock  the  biotite  is  seen  to  be  gradually  encroaching  on  broad 
surfaces  of  a  dark  hornblende  which  is  finely  luster-mottled  with  abundant 
rounded  grains  of  olivine  and  pyroxene. 

In  the  freshest  slides  the  pale-brown,  faintly  pleochroic  hornblende  is 
luster-mottled  by  rounded  masses  of  olivine  and  more  angular  pyroxene  of 


COETLANDITE. 


347 


liylit  (.•olor,  strong-  prismatic  cleavag-e  aud  abundant  twinning.  The  liroad 
liornblende  surfaces  are  also  replaced  by  an  aggregate  of  the  pyroxene 
grains,  and  thus  passes  into  the  second  type  of  the  series.  The  normal 
decomposition  is  into  talc,  and  broad  bands  centrally  blackened  by  mag- 
netite grains  pass  tln-ough  the  olivine  and  pyroxene  alike. 

The  relation  of  the  luster-mottled  hornblende  to  the  biotite  is  less  clear. 
It  seems  at  first  sight  to  be  a  superficial  change,  and  the  mica,  now  green 
and  now  brown,  is  developed  in  the  cleavage  planes  of  the  hornblende. 
But  as  it  is  luster-mottled  by  all  the  other  minerals  with  fresh  borders,  it 
was  quite  certainly  formed  originally  by  some  change  in  conditions  of 
cooling,  and  simultaneously  with  the  hornblende.  Perhaps  it  is  to  be  looked 
at  as  a  contact-metamorphic  effect,  brought  about  by  the  introduction  of 
fluorine  from  without.  There  is  associated  with  the  normal  rock  a  massive, 
friable,  granular  rock,  made  up  of  fibrous  hornblende  and  bright  emerald- 
green  pyroxene,  like  that  found  on  the  western  border  of  the  hornblende- 
granite.  Enstatite  occurs  but  rarely.  Calcite  is  quite  common,  as  soon  as 
change  sets  in.     Feldspar  is  wholly  wanting. 

An  analysis  of  the  finer-grained  and  fresher  portion  of  the  mass  was 
made  by  Mr.  L.  G.  Eakins : 

Analysis  of  cortlandite  from  Belcher  town. 


S102 

Fer  cent. 

48.63 

.47 

5.32 

.36 

2.91 

3.90 

.12 

trace 

13.04 

21.79 

.23 

.34 

2.81 

.21 

trace 

TiOi .                  

AljO, 

CrjO, 

FejOs 

FeO 

MnO .         .                      ..     . 

BaO 

CaO 

MgO 

K2O 

Na.O 

HaO 

PjOs 

CO2 , .              

100. 13 

348  GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

AGE  OF  THE  GRANITES. 

The  tonalite  cuts  the  Leyden  argiUite,  one  of  our  newest  rocks,  in 
Hatfield.  A  porphyritic  and  a  common  granite  dike  cut  the  same  argiUite 
on  the  north  line  of  the  State,  and  3  miles  south  quartz-muscovite  veins  in 
the  Bernardston  Devonian  limestone  seem  to  me  to  be  the  outermost  fila- 
ments of  the  same  granitic  intrusion.  The  pegmatite  cuts  the  tonalite.  On 
the  other  hand,  the  way  in  which  the  dikes  are  intruded  between  the  layers 
of  the  vertical  schists  would  indicate  that  this  intrusion  occurred  after  their 
upfolding,  while  the  way  in  which  the  tourmalines  are  broken  in  pieces  and 
the  great  spodumene  crystals  are  bent  and  many  times  fractured  and 
faulted  would  indicate  that  some  part  of  the  folding  has  been  done  since 
they  reached  their  present  position.  "We  may,  then,  consider  the  tonalite 
to  be  the  oldest,  the  peginatite  and  cortlandite  the  newest,  and  the  whole 
series  as  of  late  Devonian  or  Carboniferous  age.  The  porphyritic  granitite 
seems  to  be  older  and  to  have  been  influenced  more  by  the  upfolding  of  the 
region,  and  the  Hardwick  granite  is  still  older,  as  it  is  cut  by  the  porphy- 
ritic gi-anite  of  Coys  Hill. 

ElfiSTJMlfe  AS  TO  THE   GENIETIC  EELATIOKS   OF  THE   GRANITES. 

The  two  great  masses  of  tonalite  were  the  cores  of  two  batholites,  which 
came  up  at  points  on  the  two  faults  which  border  the  great  Connecticut 
River  depression. 

From  the  northeast  and  northwest  corners  of  the  Belchertown  mass 
extend  the  eastern  Connecticut  and  the  Swift  River  fault  lines,  along  which 
narrow  dikes  and  patches  of  the  tonalite  occur  far  to  the  north. 

Unlike  the  above,  the  Hatfield  tonalite  is  bordered  outwardly  in  its 
western  half  by  biotite-granite  (granitite)  and  biotite-muscovite-granite, 
and  then  both  are  much  cut  up  by  later  pegmatite  dikes  in  several  genera- 
tions, which  extend  out  into  the  suiTounding  country  in  a  broad  aureole, 
within  and  beyond  which  the  schist  is  greatly  impregnated  with  quartz  and 
considerably  more  metamorphosed  than  outside  their  influence. 

Toward  the  periphery  the  granite  dikes  carry  rare  minerals  in  great 
abundance  and  beauty,  and  these  show  two  modes  of  occurrence.  Beryl 
and  large  manganese-garnets  occur  irregularly  in  the  muscovite-granite 
dikes  of  very  coarse  grain.  Albite,  tourmaline,  and  the  minerals  of  the 
rare  earths  occur  in  secondary  dikes  of  most  puzzling  character  in  the  main 


CONTACT  EFFECTS  OF  THE  ERUPTIVE  ROOKti.  349 

pegrnutite  dikes.  The  circuiustauces  under  wliich  a  crystal  of  spoduineue 
a  yard  long-  aud  a  foot  thick  could  forui  iu  a  great  granite  dike  and  then 
be  replaced  by  albitic  granite  containing  zircon,  garnet,  and  beryl  are  diffi- 
cult to  imagine.  It  is,  perhaps,  possible  to  suppose  that  the  latter  minerals 
were  included  in  the  original  crystal,  and  then  the  change  by  the  action  of 
heated  alkaline  solutions  as  made  out  by  the  authors  cited  above  (p.  344ff) 
seems  satisfactory  for  the  explanation  of  the  main  change  into  albitic  granite. 
It  seems  to  me  that  the  succession  made  out  above — (1)  tonalite  and 
granitite,  (2)  pegmatite,  (3)  albitic  granite — was  essentially  a  series  of 
eruptions  iu  which  mineralizers  took  a  gradually  increasing  pai't,  and  that 
aqueous  agency  proper  began  with  the  formation  of  cymatolite  and  the 
other  remarkable  pseudomorphs  and  the  quartz  veins. 

C03«irTACT  EFFECTS   OF  THE  ERUPTIVE  ROCKS. 

These  rocks  penetrate  highly  crystalline  schists  and  gneisses,  and  in 
general  the  contact  effects  are  not  marked.  On  the  west  side  of  the  valley 
the  complex  spangled  stracture  of  the  Conway  schists  disappears,  the  trans- 
verse biotite  and  garnets  are  wanting,  and  the  rock  is  coarser-grained  and 
feldspathic.  On  the  east  side  it  becomes  a  coarse  fibrolite-gneiss.  In  the 
amphibolites  and  argillites  the  changes  are  more  interesting.  The  broad 
band  of  chiastolite-schists  derived  from  the  Leyden  argillite  is  described  iu 
connection  with  the  description  of  these  rocks.  The  others  are  discussed 
also  in  connection  with  the  less  altered  rocks  with  which  they  are  asso- 
ciated and-  from  which  they  have  been  derived,  as  the  purpose  of  this  study 
has  been  to  determine  the  sequence  and  proper  association  of  the  crystalline 
schists. 

Around  the  border  of  the  Belchertown  tonalite,  and  to  a  less  extent 
around  the  Hatfield  area,  are  dark-green,  friable,  granular  pyroxene  rocks, 
which  represent,  apparently,  an  effect  of  contact  metamorphism.  (See  p. 
243.)  Near  the  western  border  of  the  former  mass,  back  of  the  house  of 
T.  S.  Haskel,  the  rock  appears  near  a  great  dike  of  pegmatite. 

Also  across  the  river,  near  the  north  end  of  the  western  exposure  of  the 
tonalite,  occurs  a  biotite-  and  pyroxene-bearing  rock,  greenish-black  and 
somewhat  above  medium  grain.  Abundant  large  scales  of  biotite  give  it 
a  shining  appearance,  and  the  green  granular  pyroxene  is  often  visible, 
and  the  microscope   shows  the   finest   regular   cross-sections,   with   well- 


350  GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

developed  pinacoidal  and  prismatic  cleavages,  often  twinned  three  and  four 
fold  after  the  usual  law. 

At  the  eastern  foot  of  "The  Rocks,"  in  Hatfield,  400  feet  west  of  D. 
Glasner's,  there  occurs  a  limited  amount  of  a  peculiar  contact  product  of  the 
tonalite.  It  is  a  compact,  quartzlike,  massive  rock,  red,  mottled  with  green. 
The  reddish  parts  are  a  granular  quartz  mass,  full  of  small  red  garnets;  the 
green  parts  are  patches  of  a  pale-green  hornblende,  with  grains  of  magnetite, 
and  crystallizing  so  as  to  include  many  grains  of  the  other  constituents. 

Under  the  microscope  the  quartz  is  full  of  sheets  of  gi'anitic  fluid 
cavities,  rarely  with  moving  bubbles,  and  is  without  mlcrolites.  Feldspar 
is  represented  by  opaque  white  grains,  changed  wholly  into  a  parallel 
fibrous  mass  of  scales  of  muscovite.  Grarnet  is  in  bright  yellowish-red  clus- 
tered grains.  The  hornblende  often  contains  remnants  of  a  pale-green,  non- 
dichroic  pyroxene,  extinction  37°,  and  showing  basal  cleavage.  Beautiful 
tourmaline  crystals  appear,  which  are  strongly  dichroic,  violet  to  black, 
several  transparent  and  colorless,  but  with  black  heads,  the  rest  colorless. 

The  fibrous  hornblende  runs  through  the  mass  in  parallel  elongate 
rods,  so  as  to  strongly  recall  a  scolithus  quartzite  in  which  the  tubes  had 
been  filled  with  actinolite.  This  is  now  mostly  changed  to  a  mixture  of 
serpentine  and  calcite,  which  effervesces  strongly  with  acid  and  leaves 
behind  a  fibrous  white  mass  resembhng  tremolite,  which  seems  to  be  fibrous 
quartz. 

An  entirely  similar  rock  occurs  in  Amherst  at  the  north  end  of  Pros- 
pect street,  on  the  hillside  east  of  North  Amherst,  and  just  north  of  South 
Amherst.  At  the  first-named  locality  it  is  filled  with  bright  spangles  of 
graphite,  and  in  all  the  other  places  it  is  associated  with  the  highly  meta- 
morphosed and  granite-soaked  schists  and  appears  to  be  a  metamorphic 
rock,  and  in  the  Hatfield  occurrence  it  may  also  be  a  result  of  contact 
metamorphism.  I  hoped  for  a  long  time  to  be  able  to  prove  it  to  contain 
scolithus. 

It  seems  to  have  been  formed  as  a  contact  product  of  one  of  the  beds 
of  limestone  that  occur  in  the  Conway  schists. 


CHAPTEE   XII. 

THE  TRIAS. 

THE  COlSnsrECTICUT  RIVER  SAKDSTOKB.' 

The  Connecticut  River  sandstones  extend  northward  from  the  Sound, 
with  a  width  of  about  20  miles  across  Connecticut  and  Massachusetts  to 
Northampton;  there  they  contract  to  about  6  miles,  and  continue  north 
with  this  width  to  Bernardston,  where  they  contract  to  a  mile  in  width,  and 
soon  end  just  north  of  the  village  of  Northfield. 

Their  western  boundary  is  everywhere  coincident  with  the  foot  of 
the  bluff  of  crystalline  rocks  bordering  the  valley,  and  the  same  is  true 
of  the  eastern  border  from  the  south  line  of  the  State  northward  to  the 
Belchertown  ponds.  In  this — the  larger  portion  of  their  boundary — the 
sandstones  never  extended  much  beyond  their  present  limits,  and  show 
everywhere  shore  conglomerates  resting  against  the  schists  and  granites  on 
which  they  were  deposited. 

In  the  remainder  of  the  eastern  boundary,  from  the  ponds  north  to 
Mount  Toby,  the  boundary  of  the  sandstones  has  been  carried  by  erosion 
far  west  from  the  old  shore  line — the  line  of  the  bluffs  in  Pelham  bordering 
the  valley  on  the  east.  From  Mount  Toby  to  the  north  line  of  the  State 
the  extremely  coarse  conglomerates  which  form  the  present  eastern  portion 
of  the  Trias  must  represent  quite  accurately  the  original  eastern  shore  line, 
and  the  deep  depression  which  now  separates  these  bluffs  of  conglomerate 
from  the  escarpment  of  gneiss  that  forms  the  true  border  of  the  valley  may 
have  been  in  large  part  produced  by  the  erosion  of  Paleozoic  schists  which 
crop  out  from  beneath  the  Trias  and  occupy  the  bottom  of  this  depression. 
This  is  the  more  probable  since  this  coarse  conglomerate  is  made  up  wholly 

'The  name  Newark  was  proposed  by  Prof.  I.  C.  Russell  in  1889  for  the  Trlassic  of  the  Atlantic 

Coast.    Prof.  C.  H.  Hitchcock  supported  the  name  "The  Connecticut  Sandstone  Group"  in  Science, 

Vol.  I,  1895,  p.  74. 

351 


352       GEOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 

of  these  schists  and  argillites,  and  if  it  had  extended  across  this  depression 
ti  would  have  covered  the  beds  from  which  it  miist  have  derived  its 
material.  It  would  then  have  had  the  gneiss  for  its  shore  country,  and  the 
gneiss  must  have  supplied  a  large  part  of  its  mass.  On  the  contrary,  these 
Pelham  biotite-gneisses  seem  wholly  wanting  in  the  Mount  Toby  conglom- 
erates, from  which  I  conclude  not  only  that  the  schists  and  argillites  then 
filled  this  depression  and  furnished  the  conglomerates  a  border  nearly  on 
the  present  boundary  of  the  latter,  but  that  they  then  mantled  eastward 
over  the  gneiss.  This  demands  an  iinexpected  amount  of  erosion  dui'ing 
and  since  the  Trias. 

The  artesian  wells  that  have  been  bored  along  the  line  of  the  Connecti- 
cut with  depths  from  600  to  3,700  feet  have  never  reached  the  bottom  of 
the  sandstone.  (See  p.  380.)  If  we  add  to  this  the  height  of  the  crystal- 
line walls  of  the  valley  above  the  Connecticut,  I  think  we  may  estimate  the 
present  depth  of  the  Triassic  trough  at  somewhat  above  a  mile.  Indeed,  I 
shall  show  that  the  major  portion  of  the  material  of  the  Triassic  beds  came 
from  the  immediate  borders  of  the  basin,  and  would  thus  add  another  con- 
siderable but  unknown  quantity  to  the  maximum  depth  of  this  long  and 
narrow  trough.  I  think  the  maximum  thickness  of  the  Triassic  beds  therein, 
restoring  the  post-Triassic  and  especially  the  Grlacial  erosion,  must  have 
been  considerably  more  than  a  mile. 

I  have  elsewhere  (see  p.  13)  discussed  the  system  of  faults  bounding 
the  block,  or  group  of  blocks,  whose  sinking  formed  this  Yosemite-like 
Triassic  valley,  or  "graben,"  to  use  the  nomenclature  of  Eduard  Suess,^  and 
their  outer  boundary  can  be  closely  followed  on  the  new  four-sheet  map  of 
Massachusetts  by  tracing  the  500-foot  contour  line  at  the  foot  of  the  escarp- 
ment east  and  west  of  the  Connecticut,  though  the  fault  lines  lie  generally 
a  little  lower — that  is,  nearer  the  river. 

If  this  line  be  followed  from  the  nqrth  line  of  the  State  just  east  of  the 
Connecticut  to  the  Belchertown  ponds,  and  another  line  be  drawn  down 
the  Connecticut  to  the  mouth  of  Millers  River  and  south  to  Mount  Tom,  it 
will  include  a  long  quadrangular  area  having  its  base  at  the  northern  foot 
of  the  Holyoke  Range,  which  area  was  once  deeply  covered  by  the  Trias, 
but  has  now  been  for  the  most  part  denuded  of  this  covering.  Over  this 
area  the  crystalline  substratum  of  the  valley  stands  everywhere  about  300 

'  E.  Suess,  Das  Antlitz  der  Erde,  p.  166. 


CONNECTICUT  EIVEE  SANDSTONE.  353 

feet  above  sea  level,  instead  of  4,000  feet  below,  as  in  the  remainder  of  the 
basin.  This  I  call  the  Amherst  area.  Just  west  of  this  area,  from  Turners 
Falls  to  Northampton,  and  south  of  it  across  Hampden  County,  this  sub- 
stratum has  not  been  reached  by  borings  from  600  to  3,700  feet.  On  this 
elevated  substratum  rest  the  great  conglomerate  masses  of  Mount  Toby 
and  Gill,  rising  several  hundred  feet  above  the  adjacent  plateau  area  on 
the  east,  from  which  they  must  have  received  their  material. 

It  seems  to  me  probable  that  this  block,  bounded  by  the  Leverett  fault 
on  the  east,  the  Mount  Tom-Northfield  fault  on  the  west,  and  the  Mount 
Holyoke  faults  on  the  south,  has  experienced  a  later  movement  of  elevation 
in  opposition  to  the  prevailing  sinking  of  the  valley  blocks,  and  that  this 
explains  its  present  elevation  and  the  present  height  of  Mount  Toby. 

This  eastern  border  fault  follows  the  line  taken  by  the  railroad  east  of 
Mount  Toby;  and  on  the  east  of  the  railroad  the  conglomerates  occur  at 
the  railroad  level,  while  on  the  west  of  the  railroad  the  junction  of  the 
conglomerate  on  the  old  quartzites  below  is  about  50  feet  above  the  rail- 
road ;  so  the  uptlii-ow  of  the  conglomerate  along  its  eastern  edge  by  this 
one  fault  must  be  50  and  may  be  nearly  100  feet. 

The  upthrow  of  the  Mount  Toby  block  on  its  western  edge  is  also 
made  probable  by  the  following  considerations : 

The  great  Northfield  fault,  continuing  south  from  the  mouth  of  Millers 
River,  seems  to  pass  beneath  the  Connecticut  between  Mount  Toby  and 
Sugar  Loaf.  The  flat  top  of  Sugar  Loaf  in  this  exposed  place  seems  to  be 
due  to  the  fact  that  the  Deei-field  trap  sheet  formerly  capped  it  and  has 
been  removed  by  erosion  (probably  near  the  end  of  the  Glacial  period)  so 
recently  that  the  mesa  form  remains.  The  dip  of  the  trap  sheet  in  Mount 
Toby  is  15°  E.,  and  its  distance  from  Sugar  Loaf  is  5,610  feet.  With  this 
dip  it  would  be  carried  over  Sugar  Loaf,  936  feet  above  its  summit.  But 
the  dip  in  Sugar  Loaf  is  8°  E.,  and,  allowing  the  dip  to  change  at  the 
fault,  that  is,  about  midway  between  the  present  trap  outcrop  and  the  mesa 
top,  the  height  of  the  trap  sheet  over  Sugar  Loaf,  if  there  were  no  fault- 
ing, would  be  575  feet,  and  this  latter  number  would  be  near  the  true 

amount  of  the  upthrow  on  the  east  side  of  the  fault. 
MON  xsix 23 


354  GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

GENERAL   SECTION   OF  TRIASSIC   ROCKS. 

The  Triassic  rocks  have  been  divided  by  the  author  in  an  earher  pub- 
hcation^  as  follows: 

1.  The  Sugar  Loaf  arkose ;  or  the  sandstone  and  conglomerate  made 
up  of  the  debris  of  granite. 

2.  The  Mount  Toby  conglomerate ;  or  the  coarse  conglomerate  made 
up  of  large  schist  and  quartzite  pebbles. 

These  two  numbers  are,  speaking  generally,  the  west  and  east  shore 
deposits. 

3.  The  Longmeadow  brownstone ;  or  the  red  sandstone  generally 
marked  by  so-called  fucoidal  forms,  which  are  probably  concretions. 

4.  The  Chicopee  shale ;  or  the  calcareous  red  shale. 
These  two  are  the  offshore  and  central  beds  of  the  series. 

5.  The  Granby  tuff;  or  the  diabase-tuff. 

6.  The  Holyoke  and  Deerfield  diabase  beds. 

7.  The  Black  rock  volcanic  necks  and  the  posterior  diabase  beds. 

The  last  three  distinctions  cover  the  fragmental,  interbedded,  and  intru- 
sive occurrences  of  the  diabase,  respectively ;  except  that  the  posterior  sheet 
is  placed  with  the  injected  necks,  with  one  of  which  it  is  directly  connected. 

THE  SUGAR  LOAF  ARKOSE  OR  THE  FELDSPATHIC  SANDSTONE  AND 

CONGLOMERATE. 

This  most  persistent  and  abundant  rock  is  a  coarse,  buff  arkose  made 
up  largely  of  the  slightly  rounded  and  slightly  weathered  debris  of  a 
muscovitic  granite.  The  average  grain  is  about  an  eighth  to  a  third  of  an 
inch,  so  that  in  a  region  of  fine-grained  rocks  it  would  be  called  a  conglom- 
erate. It  is  slightly  cemented  by  iron.  It  grades  in  one  direction  into 
a  medium-grained,  buff,  micaceous  sandstone,  more  commonly  thi'ough 
coarse,  pebbly  arkose  into  a  coarse  conglomerate,  in  which  the  mass  of  the 
rock  is  the  same  coarse,  unworn  granitic  debris  and  the  larger  constituents 
are  large  rounded  pebbles — of  granite  when  the  rocks  of  the  adjacent  shore 
are  granite.  It  is  at  times  whitened  over  broad  areas  by  the  removal  of 
the  iron  cement  by  organic  agencies  and  the  complete  kaolinization  of  its 
feldspars  to  great  depths.  The  red  rock  is  first  spotted  with  green  from 
the  reduction  of  the  iron  oxide,  and  then  whitens  as  the  protoxide  salt  is 
removed  by  solution. 

'  On  the  Triassic  in  Massachusetts :  Bull.  Geol.  Soc.  America,  Vol  II,  1891,  p.  451. 


TUE  SUGAR  LOAF  ARKOSE.  355 

Offshore  the  rock  is  well  but  coarsely  bedded ;  cross-bedding  and 
coarse  rippling-  are  often  well  marked;  bands  of  comminuted  coaly  matter 
from  rotted  and  disintegrated  wood  occur;  but  all  signs  of  abandonment 
by  the  water,  as  mud-cracks,  tracks,  etc.,  are  wanting.  It  occupies  a  broad 
band  commencing  at  the  north  end  and  running  down  the  west  side  of 
the  valley,  and  expands  to  occupy  the  full  width  of  the  valley  centrally 
across  nearly  the  whole  of  Hampshire  County.  South  of  Mount  Holyoke 
it  branches,  and  across  Hampden  County  occupies  the  east  and  west  sides 
of  the  basin  in  broad  bands. 

CONTACT   AND   DISTRIBUTION. 

Along  the  western  side  of  the  valley  the  contact  of  the  shore  beds 
and  the  schists  is  first  seen  in  Bernardston,  in  the  brook  gulch  just  south  of 
the  Devonian  limestone,  and  in  the  same  pasture.  Here  there  is  a  thin 
remnant  of  the  conglomerate  resting'  on  the  basset  edges  of  the  Devonian 
quartzite  and  mica-schist,  and  it  is  made  up  of  a  coarse  red  sandstone,  full 
of  large  angular  fragments  of  the  rocks  on  which  it  rests.  There  is  here 
scarcely  more  than  a  single  layer  of  pebbles  cemented  to  the  edges  of  the 
schist. 

On  Fox  Brook  south  of  the  road  over  West  Mountain,  in  Bernards- 
ton,  the  very  coarse  arkose  can  be  seen  almost  in  contact  with  the  schists, 
showing  that  almost  from  the  beginning  the  strong  northward  tidal  currents 
carried  their  granitic  material  even  into  this  far  northern  portion  of  the 
basin.  Skirting  the  base  of  the  great  argillite  block  of  Leyden,  south 
and  west,  the  contact  is  everywhere  covered  until  Leyden  Glen,  in  the 
northwest  corner  of  Greenfield,  is  reached.  Here  is  a  brook  gorge  of  great 
natural  beauty,  affording  an  opportunity  to  study  the  extreme  contortion  of 
the  argillite,  as  well  as  to  see  the  contact  of  the  Triassic  beds  upon  the 
latter,  the  whole  dissected  out  most  beautifully  by  the  erosion  of  three 
brooks.  Just  below  the  dam  of  a  burnt  mill,  on  the  east  side  of  the  main 
brook,  a  small  stream  comes  down  over  the  argillite,  here  flat-bedded,  with 
strike  N.  10°  E.,  dip  90°,  and  has  cut  through  a  basal  stratum  of  the  Trias, 
which  is  plastered  against  the  argillite,  the  plane  of  contact  dipping  45°. 
The  stratum  is  here  made  up  of  subangular  masses,  nearly  an  inch  across, 
of  the  vein  quartz  derived  from  the  argillite,  and  is  quite  uncemented.  It 
is  1  to  1 J  inches  thick,  and  passes  gradually  up  into  a  bed,  2  or  3  inches 


356  GEOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 

thick,  containing  many  smaller  pebbles  of  the  white  vein  quartz  in  a  deep- 
red  paste.  This  graduates  into  a  deep  chocolate-colored  layer — a  coarse, 
pebbly  arkose — fall  of  muscovite  and  feldspar,  but  with  much  vein  quartz, 
and  argillite  also,  and  this  continues  upward  across  the  brook,  becoming 
lighter  in  color. 

Entering  the  gorge  of  the  next  tributary,  50  feet  lower  down  on  the 
same  side,  one  finds  that  the  brook  has  just  cut  down  to  the  argillite,  but 
traces  of  the  basal  conglomerate  bed  can  be  found  resting  nearly  horizon- 
tally on  the  vertical  slates  for  245  feet  up  the  brook.  It  is  a  striking  rock, 
from  the  large  white  quartz  pebbles  in  the  bright-red  sand.  Above  this, 
just  at  the  entrance  of  the  brook,  is  a  fine  bluff,  and  in  it  the  basal  bed 
grades  through  3^  feet  of  fine  red  sandstone  into  a  bed,  10  feet  thick, 
of  coarse  buff'  arkose  with  two  thin  conglomerate  layers,  and  above  this 
is  a  bed,  10  to  12  feet  thick,  of  a  coarse  conglomerate  with  pebbles  an 
inch  across;  strike  N.  70°  E.,  dip  15°  S.  These  are  mostly  well-rounded 
masses  of  the  vein  quartz  from  the  argillite,  also  of  gneiss,  mica-schist, 
argillite,  etc.  These  bowlders  are  often  full  of  iron  rust,  a  fact  which 
may  throw  light  upon  the  penetration  of  biotite  into  all  the  pebbles  of  the 
Cambrian  gneisses  of  Berkshire.  We  see  that  the  circumstances  favoring 
the  deposition  of  iron  rust  were  present  from  the  beginning,  and  that  after 
a  brief  period  (during  which  the  waters  advancing  upon  this  sharp  slope 
deposited  only  the  angular  quartz  masses  so  generally  abundant  in  the 
argillite,  yet  wanting  just  here,  but  which  were  transported  only  a  little 
wa}?-)  the  strong  tidal  currents  brought  up  from  the  south  the  granitic  mate- 
rial of  the  Williamsburg  area,  and  that  there  for  a  long  time  and  for  a  con- 
siderable distance  out  into  the  valley  by  far  the  larger  and  the  finer  portion 
of  the  deposit  was  this  far-traveled  granite  debris,  while  the  coarser  and 
more  angular  portion  was  vein  quartz  from  the  argillite.  The  black  mud 
from  the  latter  seems  to  have  been  swept  away  entirely  and  to  have  found 
no  place  of  permanent  deposit  north  of  Holyoke. 

The  shore  conglomerates  are  concealed  by  the  Green  River  lake-beds 
south  across  Grreenfield  and  the  north  of  Deerfield,  but  opposite  Pine  Hill 
and  the  north  part  of  Deerfield  village  the  brooks  coming  down  from  the 
west  cut  through  the  heavy  sands  of  the  high  terrace  and  expose  the  Tri- 
assic  beds  nearly  up  to  the  conglomerates,  especially  in  the  brook  south  of 
J.  F.  Hartwell's  and  in  the  roadside  running  down  into  the  valley  near  the 
Baptist  church. 


THE  SUGAU  LOAF  ARKOSE.  357 

The  rock  is  everywhere  a  coarse  piuldiug-stoue,  tlie  large  pebbles  of 
vein  quartz  and  schist  being  derived  from  the  adjacent  bluffs  of  inica-scliist 
and  growing  smaller  and  rarer  as  one  recedes  from  the  bluff  in  going  east- 
ward, until  in  the  Deerfield  River  they  are  mostly  wanting,  while  the  paste 
in  which  these  large  pebbles  are  embedded  is  a  coarse  arkose  with  much 
kaolinized  feldspar  and  muscovite,  which  could  not  have  been  furnished  by 
the  dark  schists  tlmt  make  the  shore  for  miles  north  and  south,  but  which 
have  drifted  up,  as  before  indicated,  from  the  south. 

From  this  point  on  the  arkose  abuts  against  the  western  wall  clear 
across  the  State.  The  exposures  are  poor,  but  the  shoreward  portion  is  an 
ai'kose-conglomerate  with  pebbles  rarely  larger  than  8  inch  cube.  Thus,  at 
Wliately,  in  the  roadside  near  the  school  south  of  the  village,  the  arkose 
contains  8-inch  pebbles  of  a  coarse  granite  exactly  like  that  of  Williams- 
burg, in  a  mass  of  coarse  granitic  debris,  while  the  adjacent  argillite  and 
tonalite  are  wanting. 

The  next  place  where  the  conglomerates  are  exposed  near  the  junction 
is  at  Loudville,  where  the  arkose  is  in  coarse  pebbles  2  to  3  inches  across, 
and  in  the  old  adit  the  contact  between  the  two  was  cut  through.  Here 
the  feldspar  grains  are  often  soft  kaolin. 

In  1868  Amos  Eaton  described  with  great  care  the  rocks  of  the  Loud- 
ville adit.  Beginning  800  feet  from  the  mouth,  vertical  strata  of  granite- 
schist  and  serpentine  continue  for  134  feet  east,  toward  the  tunnel  mouth. 
Then  a  "green  granular  aggregate"  appear;  which  "begins  to  approach  a 
horizontal  position."  This  continues  66  feet  and  is  followed  by  a  "granu- 
lated schistose  aggregate  chiefly  of  quartz  and  mica." 

At  480  feet  a  half-inch  coal  stratum  appears  and  runs  on  to  300  feet, 
where  it  goes  below  the  floor  of  the  adit.  The  green  aggregate  is  the  first 
Triassic  bed,  and  the  sudden  transition  seems  to  indicate  that  the  two  are 
faulted  against  each  other.  The  green  color  is  probably  due  to  the  intro- 
duction of  surface  waters  into  the  crushed  band  along  the  fault,  which 
have  reduced  the  iron  oxide  and  discharged  the  red  color.  The  sandstone 
dips  east  here,  as  the  coal  bed  indicates. 

The  next  contact  of  the  conglomerate  can  be  seen  in  Southampton,  a 
mile  south  of  Grlendale,  on  the  Great  Mountain  road.  As  usual,  it  is  a  gran- 
itic conglomerate,  but  its  coarseness  does  not  reach  that  of  the  eastern  beds. 

South  of  the  mouth  of  Westfield  River,  across  Westfield,  Southwick, 
and  into  Connecticut,  till  rests  against  the  bold,  continuous  bluff  and  con- 


358  GEOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 

ceals  the  shore  conglomerates.  This  till  stretches  half  across  the  Westfield 
Valley  and  extends  a  long  way  south,  and,  curiously,  in  the  portion  adjoin- 
ing the  bluflf  of  crystalline  rocks  it  is  made  up  almost  wholly  of  the  arkose, 
while  its  thicker  central  portion  is  composed  of  coarse  granitic  materials. 

The  Triassic  shore  conglomerates  are  largely  concealed.  Only  in  one 
place  (Mrs.  S.  Grillett's),  near  where  the  Grranville  road  goes  over  Sodom 
Mountain,  in  the  southwest  portion  of  Southwick,  is  the  rock  seen  in  place, 
within  50  rods  of  the  base  of  the  bluff.  It  is  here  a  coarse,  flaggy  arkose, 
the  mass  of  the  rock  a  coarse,  buff,  feldspathic  sand,  with  a  few  far-traveled 
pebbles  of  quartz  1  to  3  inches  long.  Skirting  the  base  of  the  bluff  for 
miles  the  abundant  fragments  in  the  till  show  that  this  is  the  prevailing 
rock.  It  is  often  so  well  cemented  and  so  little  worn  that  it  closely 
resembles  a  granite.  Sti'etching  east  across  Westfield  and  Southwick  to  the 
railroad  the  rock  is  uniformly  a  loosely  cemented  mass  of  unworn  granitic 
debris,  quite  deep  red  in  the  interior,  but  bleached  and  kaolinized  at  the 
surface,  and  very  often  dug  into  for  i-oad  material  It  is  commonly  more 
or  less  spotted  with  well-rounded  and  therefore  far-traveled  quartz  and 
granite  pebbles  1  to  4  inches  across. 

THE  MOUNT  TOBY  CONGLOMERATE,  OR  THE  SLATE  AND  QUARTZITE 

CONGLOMERATE. 

This  rock  never  anywhere  sinks  to  the  dimensions  of  a  sandstone,  but 
varies  from  a  conglomerate  with  its  coarse  pebbles  2  inches  long  to  one 
where  the  larger  constituents  are  from  2  to  4  feet  in  length.  The  mass  of 
the  rock  is  very  largely  and  often  wholly  made  up  of  comminuted  argillite, 
quartz-schist,  and  vein  quartz,  with  the  larger  pebbles  of  the  same  material. 

In  many  cases,  as  along  the  eastern  slope  of  Mount  Toby  and  in  Grill, 
it  deserves  the  name  of  a  giant  conglomerate,  blocks  from  1  to  2  feet  long- 
being  stuck  as  closely  as  they  can  lie  in  a  coarse  gravel  from  which  all  sand 
has  been  washed.  An  arrangement  of  the  constituents,  often  very  partial, 
with  their  flat  surfaces  parallel  to  a  common  plane  and  a  rude  stratification 
in  coarser  and  finer  beds  is  the  only  structure.  The  rock  occupies  the  east 
shore  of  the  basin  except  in  the  central  portion. 

CONTACT    AND    DISTRIBUTION. 

The  most  northern  outcrop  of  the  Trias  occurs  a  half  mile  north  of 
Northfield,  where  the  Winchester  road  starts.  It  is  a  coarse  conglomerate, 
which  appears  in  continuous  outcrops  west  of  the  village  street,  and  may 


THE  MOUNT  TOBY  CONGLOMERATE.  359 

be  best  stiuliiMl  hi  tlio  fine  roclies  inoutoiuKJCS  iu  front  of  the  church  erected 
recently  by  Mr.  1).  L.  Moody  and  along  the  brook  near  by,  down  a  little 
west  to  the  gristmill.  Here  the  pudding-stone  contains  pebbles  of  granite, 
quartzite,  and  amphibolite.  One  block  of  a  flat,  bai-ren  mica-schist  was  2 
feet  long.  The  whole  series  comes  from  the  escarpment  of  crystalline 
rocks  directly  east,  and  the  great  fault  at  the  foot  of  this  escarpment  is 
about  100  rods  east,  and  that  represents  the  probable  distance  of  the  shore 
line.  A  mile  farther  south,  at  the  south  end  of  the  village,  the  conglom- 
erate contains  pebbles  of  the  peculiar  coarse  hornblende  rock  that  crops 
out  in  the  lower  portion  of  the  escarpment  due  east,  and  there  only,  which 
indicates  that  these  conglomerates  have  spread  thinly  from  the  foot  of  the 
scai-p  less  than  a  mile  east,  the  spreading  being  due  to  a  gradual  transgres- 
sion of  the  waters  of  the  Triassic  bay.  The  area  just  described  seems  to  be 
now  almost  isolated  by  erosion,  and  from  this  point  south  to  the  mouth  of 
Millers  River  the  Connecticut  may  run  wholly  on  crystalline  rocks  beneath 
the  Champlain  sands,  and  the  narrow  shelf  between  the  river  and  the 
east-side  escarpment  of  the  valley  has  been  stripped,  largely,  I  have  no 
doubt,  by  the  ice  of  the  shore  deposits  which  once  covered  it. 

The  section  at  the  mouth  of  Millers  River  is  interesting  and  peculiar. 
The  farthest  bluff  visible  on  the  south  side  of  the  Connecticut  to  one  stand- 
ing at  the  mouth  of  the  tributary  is  the  coarse  conglomerate  of  the  Trias. 
To  reach  it  one  passes  along  the  shore  over  a  coarse  muscovite-granite, 
rudely  parallel  and  fissured  by  pressure,  and  comes  at  a  small  brook  course 
up)on  an  outcrop  of  the  Leydeu  argillite  and  quartz-schist,  wholly  crushed 
and  slickensided.  This  continues  a  few  rods  and  is  followed  to  the  west  by 
the  conglomerate.  This  is  the  coarsest  shore  breccia,  wholly  derived  from 
the  adjacent  argillite  and  showing  no  granitic  material.  Many  blocks  are 
3  feet  long;  one  was  measured  43  inches  long.  The  junction  is  not  well 
exposed,  but  seems  to  be  nearly  vertical,  and  the  whole  region  is  one  of 
intense  crushing  and  faulting,  though  there  is  no  indication  of  great  throw. 

The  conglomerate  is  exposed  along  the  river  about  25  rods,  only  a 
part  of  its  true  thickness,  and  dips  40°  N.  (strike  N.  80°  E.)  beneath  the 
sandstone,  a  thin-bedded,  gray,  shaly  rock,  which  for  many  rods  is  crushed 
into  a  mass  of  slickensided  pencils.  It  also  for  a  considerable  distance  has 
strike  N.  80°  E.,  dip  30°  W.,  and  then  changes  suddenly  to  strike  N.  80° 
W.,  dip  40°  S.,  and  in  a  little  distance  one  comes  on  a  well-known  "bird 
track"  quarry. 


360       GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

The  conglomerates  are  concealed  beneath  the  broad  sand  plains  of 
Montague,  but  rise  in  the  great  mass  of  Mount  Toby  to  their  greatest 
height  and  their  most  extensive  development.  The  steep  walls  of  the  deep 
gorge  which  borders  this  mountain  on  the  east  show  sheer  cliffs  and  enor- 
mous bowlders  of  the  coarsest  conglomerate,  and  high  above  the  bottom  of 
the  valley,  in  the  beds  of  Roaring  Brook  and  of  the  next  brook  to  the 
north,  the  contact  of  this  conglomerate  on  an  ancient  quartzite  can  be  seen. 

This  mountain  is  a  slate-conglomerate  from  base  to  summit  and  from 
its  eastern  slopes  west  nearly  to  the  Connecticut.  High  up  on  its  western 
slope  are  two  bands  of  fucoidal  sandstone,  which  penetrate  the  mountain 
with  slight  eastward  dip,  and  indicate  two  horizons  at  which  a  deepening 
of  the  water  sent  the  finer  sediment  far  east  over  the  shoreward  con- 
glomerates. The  high  level  (310  feet  above  the  sea)  at  which  the  rocks 
of  the  South  Leverett  plain  pass  beneath  the  conglomerate,  and  the  rising 
of  the  whetstone  and  amphibolite  through  it  at  Whitmores  Ferry,  show 
that  the  rock  is  not  above  a  thousand  feet  thick. 

From  Mount  Toby  to  Belchertown  Pond  the  shore  conglomerates  are 
wholly  removed  by  erosion.  Some  of  the  most  interesting  exposures  of 
the  shore  conglomerates  on  the  east  side  of  the  valley  occur  in  Wilbraham. 
Just  east  of  the  academy,  after  passing  a  bend  and  slight  rise  in  the  road, 
one  comes  upon  outcrops  of  a  dull-brown,  rotted  conglomerate,  so  soft  that 
it  is  dug  into  for  road  material.  It  is  exposed  along  the  south  side  of  the 
road  for  80  feet.  Just  to  the  east  a  highly  indurated  muscovitic  quartzite, 
full  of  quartz  veins  and  of  dark  color,  rises  sharply  to  foi'ih  the  eastern 
escarpment  of  the  valley.  The  conglomerate  rests  against  this  and  only  a 
few  feet  of  turf  covers  the  line  of  junction.  This  is  marked  by  a  slight 
depression  which  crosses  the  road  obliquely,  east  of  which  the  ground  rises 
rapidly  and  is  covered  by  the  large  light-colored  bowlders  of  the  schist. 
All  or  nearly  all  of  the  pebbles  of  the  conglomerate,  1  to  8  inches  long,  are 
from  this  schist. 

A  medium-  to  fine-grained  red  sandstone  occurs  west  of  the  conglom- 
erate and  can  be  traced  in  the  bed  of  the  road  right  up  to  the  conglomerate, 
where  the  two  are  seen  only  2  or  3  feet  apart,  and  the  sandstone  either  runs 
under  the  conglomerate  or  the  two  abut  by  an  irregular  fault.  The  latter 
is  by  far  the  most  probable,  as  the  sandstone  dips  15°  W.,  while  the  con- 
glomerate is  horizontal,  and  the  transition  would  be  very  abrupt  if  the 
sandstone  went  underneath. 


TEE  MOtTNT  TOBY  CONGLOMKRATli.  3(U 

Great  ledges  of  the  coarse  rock  stretch  away  soutli  and  have  Ihe 
abnormal  attitude,  strike  N.  G0°  W.,  dip  30°  N.,  thus  inakmg  the  existence 
of  a  fault  here  tlie  more  pi-obable.  This  is  just  the  position  of  the  main 
east  fault  at  the  foot  of  the  east  scarp  of  the  valley. 

The  exact  contact  of  the  two  rocks  may  be  seen  in  the  bed  of  the 
l)r()()k  which  crosses  the  road  just  south  of  the  village  (south  of  J.  Holman's), 
by  following  the  brook  east  to  the  foot  of  the  scarp.  Here,  resting  on  the 
black  crushed  and  silicified  schist,  is  a  compact  pudding-stone  with  abun- 
dant pebbles,  about  4  inches  long,  of  the  schist  in  a  ground  of  deep-red 
sandstone.  We  have  here  the  combination  of  finer  far-traveled  and  coarser 
local  material,  discussed  more  in  detail  below  (p.  374).  From  this  point 
heavy  kame  gravels  cover  all  the  shore  deposits  far  into  Connecticut. 

THE    OUTCROPS    OF    CRYSTALLINE    ROCKS    IN    THE    MIDST    OF    THE    MOUNT    TOBY 

CONGLOMERATES. 

The  Conway  hornblende-  and  quarts-schists  at  Whitmores  Ferry,  in  Sunder- 
land.— I  had  long  maintained  that  the  conglomerate  of  Mount  Toby  could 
not  be  above  1,000  feet  thick,  and  that  it  must  have  a  base  about  300  feet 
above  the  river,  so  that  the  discovery  of  large  outcrops  of  the  underlying 
masses  in  the  heai't  of  the  Mount  Toby  conglomerates  was  very  gratifying 
to  ine.  It  has  proved  very  useful,  as  well  in  throwing  light  upon  the  dis- 
tribution of  the  older  rocks  beneath  the  Trias  as  in  accounting  for  the 
source  of  the  materials  of  a  large  portion  of  the  conglomerates  and  the 
extreme  coarseness  of  those  conglomerates  at  large  distance  from  the  old 
shore  bluffs,  which  seemed  to  be  the  only  source  for  them.  Several  of  the 
rocks  outcropping  thus  are  unique  and  their  presence  in  abundance  in  the 
conglomerate  had  long  been  a  puzzle  to  me.  Again,  at  certain  points  in 
the  mountain  far  from  the  shore,  the  pebbles  of  the  conglomerate  swell 
suddenly  to  large  size  and  maintain  such  size  for  a  limited  area  around  the 
central  point.  This  has  now  enabled  me  to  locate  several  outcrops  of 
crystallines  in  the  midst  of  the  clastic  rocks. 

The  first  area  discovered  was  the  more  interesting,  as  it  forms  the 
whole  or  part  of  the  ledges  over  which  the  waters  of  the  mill  at  Whitmores 
Ferry  run,  east  of  the  road,  while  west  of  the  road  they  pass  over  the  black 
fish-bearing,  slialy  sandstones.  The  crystalline  rock  is  here  a  black,  fine- 
grained and  thin-bedded  amphibolite,  and  that  it  has  not  been  recognized 
as  distinct  from  the  black  fish-bearing  sandstone  is  not  surprising.     Upon 


362       GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

the  plateau  above,  just  south  of  the  mill  pond,  is  a  series  of  roches 
moutonn^es,  and  an  examination  of  these  reveals  a  very  interesting  state  of 
things. 

The  western  well-smoothed  ledge  is  at  its  north  end  a  dark-green, 
very  fine-grained  amphibolite,  striking  north  and  standing  vertical,  full  of 
wavy  quartz  veins  and  lenses  placed  with  the  bedding.  The  whole  is 
little  jointed,  but  a  few  feet  along  the  surface  the  traces  of  jointing  increase 
in  distinctness,  and  farther  south  become  slightly  opened  planes,  and  then 
traces  of  motion  of  the  fragments  are  seen,  and  infiltrated  sand  now  indu- 
rated in  the  joints.  This  disturbance  increases  slowly  until  all  the  frag- 
ments are  thrown  into  confusion,  but  one  can  see  how  they  may  be  moved 
back  into  their  places.  Three  rods  from  the  beginning  the  whole  is  a 
breccia  of  large  plates  of  the  parent  rock ;  at  10  rods  one  begins  to  see 
foreig'n  pebbles — quartz  and  gneiss — and  for  a  mile  south  the  amphibolite 
pebbles  can  be  found  in  abundance.  East  of  the  amphibolite,  which  is 
perhaps  10  rods  wide,  is  a  band  of  light-gray,  fine-grained,  thin-  and 
flat-laminated  quartz-schist  (whetstone),  and  still  farther  east  is  a  second 
adjoining  bed  of  the  fine-grained  amphibolite.  The  first  bed  forms  the 
face  of  the  bluff",  and  the  water  pours  over  it,  and  it  can  be  examined 
along  the  path  up  to  the  dam.  All  these  show,  southward,  a  full  repeti- 
tion of  all  that  has  been  described  for  the  first  band,  and  the  quartz-schist 
is  more  abundant  in  the  conglomerate  and  more  characteristic  of  it  than 
any  other  rock.  For  the  age  and  microscopic  character  of  these  rocks, 
see  page  196. 

The  Bernardston  gneiss  of  the  hill  west  of  Montague. — On  the  northei'n 
slope  of  this  hill,  near  the  house  of  H.  H.  Taylor  (now  burned),  with  its 
center  at  the  branching  of  the  road  at  the  most  northerly  loop  of  the  320- 
foot  contoixr  on  the  map,  is  a  large  outcrop  of  a  spotted,  thin-  and  wavy- 
bedded  gneiss,  with  a  greenish,  greasy  sheen  of  its  mica,  which  shows 
traces  of  pebbles  and  agrees  with  the  South  Vernon  gneiss  modification 
of  the  Bernardston  quartzite.  It  is  a  large,  outcrop,  as  the  ice  has  planed 
the  conglomerate  off*  from  the  whole  north  face  of  the  hill,  and  its  similar 
position  to  that  of  Mount  Warner,  in  the  Amherst  basin,  is  interesting. 
This  was  a  great  hill  in  the  Trias,  and  furnished  material  in  large  amount 
as  the  waters  rose  over  it.  To  the  north  the  Triassic  rock  grows  rapidly 
finer,  but  the  long  exposures  in  the  bed  of  the  stream  at  the  foot  of  the 


THE  MOUNT  TOBY  OONULOMERATB.  363 

liill,  a  huudrc'd  rods  north,  are  a  coarse,  pebbly  sandstone,  derived  almost 
wholly  from  this  peculiar  rock. 

All  around  the  south  border  of  the  gneiss  the  outci-ops  of  the  junction 
an-  very  fine,  and  one  can  see  the  ledge  undisturbed,  passing  gradually 
through  the  stages  described  above  at  Whitmores  Ferry  until,  at  a  distance 
of  a  few  rods,  a  coarse  conglomerate  is  formed,  in  which  I  measured  one 
egg-shaped  block  47  inches  long;  and  in  the  whole  hill  to  the  south  for 
miles  the  large  glacial  bowlder's  of  this  rock  are  so  abundant  that  I 
searched  specially  for  an  outcrop  of  the  older  rock,  and  found  it  here. 
The  conglomei'ates  are  thrown  off  in  all  directions  from  this  mass,  and  in 
the  brook  dip  30°  E.,  away  from  the  hill.  The  gneiss  bowlders  weather 
more  rapidly  than  the  fine  paste,  and  form  great  holes  in  the  conglomerate. 

At  the  most  northern  point  in  the  south  wood  road,  on  Mount  Toby, 
is  probably  another  similar  outcrop,  as  pebbles  40  to  45  inches  occur,  and 
3  rods  east  of  the  east  end  of  this  road  is  another  outcrop  of  a  fine  granite 
protruded  through,  the  conglomerate. 

Breccia  at  North  Amherst — Just  east  of  the  North  Amherst  railroad 
station,  in  a  pasture  a  few  rods  southeast  of  the  point  where  the  road  turns 
south,  and  at  the  Grolden  Gate  dam,  a  half  mile  east,  occurs  a  coarse,  rusty 
breccia  of  gneiss  pebbles  and  quartz  and  feldspar  grains. 

In  one  slide  a  large  pebble  of  an  even-bedded  biotite-gneiss  is  embedded 
in  finer  material.  In  another  many  rounded  grains  of  a  fine-grained  gneiss, 
often  cracked  and  distorted,  appear  in  a  clastic  paste.  This  has  in  many 
places  tlie  appearance  of  a  coarse  conglomerate  distorted  by  pressure,  and 
I  was  at  one  time  inclined  to  consider  it  a  portion  of  the  mica-schist,  gneiss, 
and  granite  crushed  in  place,  recemeuted,  and  much  weathered.  In  places 
it  is  shot  through  with  calcite  veins. 

As  soon  as  I  had  studied  the  contact  of  the  Triassic  conglomerate  on 
the  gneiss  at  the  exposure  west  of  Montague  Center,  I  was  struck  by  the 
similarity  of  the  two,  as  well  as  by  the  resemblance  of  this  occurrence  to 
that  at  the  Williams  farm,  at  Bernardston.  It  seems,  then,  to  be  the  contact 
layer  of  the  Triassic  conglomerate  on  the  granite. 

ACTION  OF  ICE  IN  THE  TRIAS. 

All  these  contacts  present  peculiarities  which  strongly  suggest  the 
presence  of  ice  during  the  formation  of  the  coarse  breccias,  especially  the 
Whitmores    Ferry  beds.     It  is  very  hard  to  understand  how  the   large 


364       GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS, 

angular  blocks  can  have  been  moved  from  their  place  and  carried  hori- 
zontally southward,  as  they  have  been,  without  the  intervention  of  shore 
ice.  In  a  valuable  rdsumd  of  the  evidence  bearing  upon  the  question  of  the 
existence  of  Triassic  glaciers  Professor  RusselP  has  expressed  his  conclu- 
sion as  follows: 

The  absence  of  glacial  records  seems  to  warrant  the  conclusion  that  glaciers  did 
not  enter  the  basins  in  which  the  Newark  rocks  were  deposited.  It  does  not  follow, 
however,  that  the  Appalachians  were  not  occupied  by  local  glaciers.  The  suggestion 
that  these  mountains  were  higher  in  the  Newark  period  than  now  and  were  covered 
with  perennial  snow  while  the  adjacent  lands  enjoyed  a  mild  climate,  seems  an 
attractive  and  very  possible  hypothesis,  but  definite  evidence  as  to  its  verity  has 
not  been  obtained. 

With  this  conclusion  I  agree,  as  I  have,  after  much  searching,  found  no 
decisive  proof  of  the  advance  of  glaciers  into  the  Triassic  basin,  but  much 
that  suggests  the  presence  of  shore  ice. 

THE  LONGMEADOW  SANDSTONE. 

This,  the  well-known  building  stone,  is  a  deep-red  sandstone  of  rather 
coarse  grain,  usually  quite  quartzose  and  with  abundant  cement  of  hem- 
atite. Both  the  Sugar  Loaf  arkose  and  the  Mount  Toby  conglomerate, 
but  more  comjnonly  the  latter,  grade  into  this  rock.  It  is  generally 
subsequent  to  the  first  outflows  of  trap,  but  both  in  Greenfield  and 
in  Agawam  underlies  in  part  the  Deerfield  and  Holyoke  traps,  respec- 
tively. Round  or  slightly  flattened  rods  of  sandstone  one-fourth  to  one- 
half  inch  across,  often  transverse  to  the  bedding,  often  interlaced,  are 
everywhere  abundant  and  characteristic,  and  at  times  the  whole  mass  of  the 
sandstone  is  made  up  of  these  problematical  forms,  commonly  called  fucoids. 
They  seem  to  me  to  be  ferruginous  concretions  formed  in  the  sand  by  iron- 
bearing  solutions  derived  from  the  diabase.  They  are  so  uniformly  present 
in  the  beds  of  this  subdivision  that  they  have  almost  the  value  of  a  charac- 
teristic fossil,,  and  I  have  fallen  into  the  habit  of  calling  the  rock  the 
fucoidal  sandstone.  Mud-cracks,  rain-dj-ops,  glazed  and  curdled  surfaces, 
tracks,  and  all  indications  of  short  and  frequent  emersion  from  the  water  are 
very  abundant. 

The  rock  appears  in  an  isolated  area  in  the  region  around  Grreenfield, 
and  occupies  the  center  of  the  basin  from  the  tufi^  beds  in  South  Hadley 
southward.     It  is  well  exposed  at  the  quarry  near  Mr.  E  H.  Lyman's  house, 

'Correlation  Papers,  The  Newark  System:  Bull.  U.  S.  Geol.  Survey  No.  85,  1892,  p.  53. 


THE  LONdMEADOW  SANDSTONE.  365 

the  first  house  south  of  Tittuis  I'ier,  in  South  Hadley,  and  contains  hei'e 
iiian\-  curious  inclusions  of  angular,  flat  pieces  of  a  buff  indurated  clay, 
which  have  been  formed  by  the  drying,  cracking,  and  warping  of  a  clay 
bod  exposed  at  low  tide,  and  then  the  sweeping  of  the  angular  fragments 
into  tlieir  present  position  in  the  sand.  It  contains  also  scales  of  graphite 
in  considerable  number,  and  this  continues  south  to  Holyoke  in  the  sand- 
stone and  the  tuff.     The  "fucoids"  are  especially  abundant  in  Springfield. 

Forty  rods  north  of  the  above  quarry,  at  the  west  end  of  the  sand- 
stone bluff  which  overhangs  the  brook,  and  about  18  feet  above  the  water 
of  the  brook,  which  here  runs  on  the  Holyoke  trap,  there  are  many  angular 
fragments  of  limestone  up  to  an  inch  in  length.  It  is  a  coarse,  crystalline 
limestone,  containing  much  tremolite,  and  more  rarely  plagioclase  and 
wernerite. 

This  rock  and  the  coarse  scales  of  gi'aphite  came  probably  from  the 
Archean  area  about  the  headwaters  of  the  Westfield  River,  and  after  enter- 
ing the  basin  were  drifted  northeast,  with  the  prevailing  current,  to  their 
present  situation,  though  there  is  a  nearer  and  much  more  abundant 
source  for  the  graphite  in  the  Brimfield  schists  to  the  east,  and  this  schist 
carries  also  thin  beds  of  limestone  with  coccolite  and  garnet. 

FRAGMENTS    OF   WHITE    TRAP   WITHOUT    AUGITE    IN   THE    SANDSTONE    ABOVE   THE 

HOLYOKE    SHEET. 

A  tuffaceous  agglomerate  occurs  in  the  second  sandstone  of  the 
Holyoke  range,  containing  a  colorless,  wholly  feldspathic  trap. 

The  great  sheet  of  trap  which  forms  Mount  Holyoke  flowed  out 
quietly  and  was  immediately  covered  by  fine  calcareous  mud  in  the  cen- 
tral parts  and  by  coarser  sands  nearer  the  borders  of  the  basin.  I  had  sup- 
posed that  it  remained  covered  during  all  the  subsequent  time  of  Triassic 
deposition,  and  contributed  nothing  except  by  ferruginous  solutions  to 
the  sandstones  that  cover  it.  Recently  my  students  in  geology  from  the 
senior  class  of  1896  at  Amherst  discovered  an  interesting  deposit  of  tuff 
between  the  Forest  Park,  or  Little  Mountain,  plug  and  Mount  Tom.  It 
lies  in  the  bed  of  the  brook  which,  flowing  north  between  the  main  and 
posterior  sheets,  crosses  the  railroad  at  the  burnt  mill  north  of  Smiths 
Ferry.  The  bed  occurs  near  the  headwaters  of  the  brook,  below  a  bridge, 
and  is  exposed  for  about  18  rods.     It  is  a  rather  coarse,  dark-greenish 


366  GEOLOGY  OP  OLD  HAMPSHIEE  COUNTY,  MASS. 


sandstone,  with  many  quai'tz,  muscovite,  and  graplaite  grains  and  scales 
visible  to  the  eye.  It  is  thick-bedded  or  massive,  changing  suddenly  from 
the  thin-bedded  sandstone.  Its  full  thickness  is  not  exposed.  It  is  very 
calcareous,  and  I  think  it  possible  that  it  may  be  the  bed  of  limestone  marked 
near  here  by  President  Hitchcock  on  his  maps,  which  I  have  not  before 
found  so  far  north. 

In  this  calcareous  sandstone  are  small  rootlike  concretionary  bodies, 
which  appear  in  the  rusted  rock  as  minute  tubes  rarely  branching-.  They 
reach  one-half  inch  in  length,  and  at  most  one-eighth  inch  in  diameter.  In 
the  fresh  rock  they  appear  as  white  calcareous  bodies,  with  a  trace  of  longi- 
tudinal fibrous  structure,  remotely  suggesting  a  minute  branching  chsetetes. 

In  this  sandstone  are  many  wholly  angular  fragments,  from  1  to  4 
inches  long,  of  a  volcanic  rock,  which  may  often  make  up  a  quarter  of  the 
mass  of  the  whole  bed.  In  fresh  fracture  it  is  a  white  or  light-gray,  fine- 
gi'ained  rock,  with  exactly  the  look  of  a  somewhat  siliceous  limestone 
spotted  with  small  grains  of  pyrite.  Weathering  or  careful  study  with  the 
lens  brings  out  the  fact  that  the  rock  is  amygdaloidal,  with  small  cavities, 
mostly  sphei'ical,  wliich  are  filled  with  calcite  or  pyrite,  or  both,  and  rarely 
the  reflection  of  a  minute  twinned  plagioclase  lath  can  be  seen  in  the  solid 
rock.  In  a  thin  slide  it  is  found  to  be  a  diabase  considerably  altered,  but 
preserving  a  close  resemblance  in  many  particulars  to  the  Mount  Holyoke 
trap,  but  more  to  the  abnormal  red  trap  from  Cheapside.  (See  p.  431.)  It 
has  the  same  distant  feathery  groups  of  larger  plagioclase  of  first  consolida- 
tion (0.8"™  long),  just  visible  to  the  eye  and  containing  rounded  inclusions 
of  glassy  magma,  and  these  lie  in  an  ophitic  network  of  plagioclase  laths 
of  two  sizes,  the  one  in  quite  stout  rods,  0.4™°'  long,  which  are  scattered 
abundantly  in  a  reticulate  or  stellate  ground  consisting  of  very  fine  needles 
of  plagioclase,  0.03-0.04™™  long.  Both  the  finer  feldspars  are  distinctly 
fibrous,  a  structure  which  is  caused  by  lines  and  rows  of  minute  grains  of 
a  dark  ore,  which  is  doubtless  limonite,  and  was  originally  hematite,  as  in 
the  Cheapside  trap.  This  makes  up  almost  the  whole  content  of  iron  in  the 
rock,  as  only  one  uncertain  augite  grain  could  be  detected.  There  is  no 
magnetite  or  chloritic  decomposition  product  except  a  trace  of  an  amorphous 
green  constituent  in  the  amygdules. 

To  complete  the  resemblance  to  the  Cheapside  rock,  the  small  round 
cavities  are  lined  by  a  secondary  growth  of  fresh  albite  in  well-shaped 


THE  LONGMEAUOW  SANDSTONE.  367 

twiiiued  crystals  .03  to  .04"""  long,  maximum  extinction  17°.  When  the 
calcite  is  dissolved  they  appear  perfectly  limpid  and  fresh,  and  often 
sliow  the  marked  undulatory  extinction  characteristic  of  aqueous  albite. 
One  of  the  larger  feldspars  of  first  consolidation,  cut  paralled  to  M  (010), 
showed  the  optical  figure  almost  central,  with  the  axial  plane  at  103°  to  the 
A'ertical  axis  of  the  crystal,  thus  having  all  the  characteristics  of  albite. 
The  smaller  feldspars  are  more  basic.  All  the  constituent  feldsjoars  are 
dusted  with  kaolin,  but  their  properties  can  be  made  out  clearly.  The  rock 
may  have  been  bleached  somewhat  by  acid  waters  and  the  iron  may  be 
now  present  in  the  pyrite,  but  when  the  calcite  is  dissolved  with  acid  the 
rock  seems  little  decomposed,  and  it  is  of  the  same  character  throughout 
the  compact  mass  from  surface  to  center. 

It  must,  therefore,  have  difiFered  materially  from  the  Cheapside  trap 
when  fresh,  although  more  like  it  than  any  other  variety  in  the  Trias. 
The  large  amoimt  of  calcite  in  the  bed  indicates  a  considerable  body  of 
lava  as  its  origin.  The  wholly  angular  character  of  the  fragments  was  due 
to  an  explosive  eruption  not  far  distant.  I  have  little  doubt  that  the  focus 
of  this  eruption  is  to  the  east,  along  the  old  main  fissure,  concealed  by  the 
masses  of  the  Forest  Park  plug  and  the  newer  sandstones. 

DISTURBANCES  IN  THE   SANDSTONES   AND   INCLUSIONS   OP   TRAP   FRAGMENTS   JUST 

BELOW    THE    POSTERIOR    SHEET. 

Where  the  western  lobe  of  sandstone  passes  down  between  the  areas 
of  trap  which  extend  north  from  the  region  of  the  Little  Mountain  core  the 
dark-gray  sandstone,  at  a  horizon  just  below  the  posterior  sheet,  is  much 
contorted,  bands  of  the  sandstone  being  twisted  into  sharp  zigzags  in  a  few 
inches.  It  makes  the  impression  of  some  local  disturbing  force  acting  before 
the  hardening  of  the  sand  to  rock,  like  the  "wallows"  in  the  sandstone  at 
Turners  Falls,  formed  by  the  crowded  tracks  of  the  great  reptiles.  At 
other  localities  along  the  western  part  of  the  eastern  lobe  of  sandstone 
which  projects  into  the  trap  area  this  disturbed  layer  is  covered  by  sev- 
eral feet  of  undisturbed,  flat-bedded  sandstone,  the  disturbed  sandstone 
graduating  rapidly  into  the  undisturbed  rock  and  showing  the  contortion  to 
have  been  produced  before  the  deposition  of  the  latter.  There  are  a  few 
small  anticlines  in  the  rocks  at  this  place  which  are  easily  distinguished 
from  the  structure  in  question.  The  band  is  the  more  interesting  because 
it  contains  angular  fragments,  6  inches  long,  of  the  common  black  trap, 


368       GEOLOGY  OP  OLD  HAMPSHIEE  COUNTY,  MASS. 

like  that  of  the  Holyoke  range,  together  with  small  fragments  of  a  white 
rock,  like  the  white  trap  described  above  (see  p.  365),  but  not  showing 
pyrite  or  porous  texture.  I  associate  these  disturbances,  and  similar  ones 
that  appear  beneath  the  posterior  sheet  as  far  north  as  the  latter  can  be 
traced,  with  the  bed  of  white  trap  described  above.  They  possibly  rep- 
resent the  border  of  an  explosive  eruption  of  limited  extent,  whose  tuffs 
may  have  locally  loaded  the  muddy  floor  of  the  estuary  so  as  to  have  pro- 
duced the  crumpling  of  the  beds,  but  the  outcrops  are  insufficient  to  give 
the  whole  history  of  the  deposit. 

It  may  be  noted  that  the  small  sills  which  appear  a  few  feet  below  the 
posterior  sheet  90  rods  north  and  150  rods  south  of  this  area  greatly  contort 
the  sandstones,  and  the  disturbances  here  noted  may  be  due  to  the  same 
cause. 

THE  BOUNDARY  OF  THE  LONGMBADOW  SANDSTONE. 

The  northern  boundary  of  the  sandstone,  in  Gill,  is  very  complicated, 
because  here  at  the  northern,  narrowed  end  of  the  central  sand  flats  the 
feldspathic  gravel  at  times  projected  far  out  over  the  sands  from  the  west 
and  the  slate  gravels  from  the  east.  The  area  of  the  sandstone  narrows  as 
one  goes  down  in  the  beds,  so  that  in  their  undisturbed  state  the  central 
sandstone  graduated  east,  west,  and  north  into  the  two  conglomerates,  with 
many  intercalated  lobes ;  and  now  that  they  are  tilted  and  faulted  one  finds 
many  sudden  changes  from  the  straight,  sudden  fault  boundaries  to  the 
complex,  lobed  line  of  passage  of  sandstone  into  conglomerate.  Especially 
marked  is  the  narrow  band  of  fine,  deej)-red,  shaly  sandstone  which  rests 
upon  the  trap  and  follows  it  north  nearly  to  the  fault  in  the  latter  on  the 
Turners  Falls  road.  This  suddenly-appearing  and  exceptionally  fine-grained 
bed  seems  due  to  the  shallowing  and  obstructing  of  the  bay  by  the  out- 
pouring of  the  trap. 

Because  of  the  prevalent  easterly  dip  of  the  rocks  the  boundaries  of 
the  sandstones  upon  the  arkose  present  along  their  western  border  the  nor- 
mal relations,  and  the  arkose  passes  regularly  below  the  sandstone.  Along- 
the  eastern  border  of  the  northern  basin  the  sandstone  dips  beneath  the 
conglomerate,  and  it  is  proved  to  pass  far  beneath  the  upper  beds  of  the 
conglomerate,  because  it  is  twice  brought  up  by  faults  and  repeated  upon 
the  western  slope  of  Mount  Toby,  once  at  the  500-  and  once  at  the  700-foot 
contour,  as  seen  in  the  sectional  view  of  the  mountain  on  the  section  sheet 


THE  GEANBY  TUFF. 


369 


(PI.  XXVIII).  This  indicates  that  after  the  deposition  of  the  major  portion 
of  the  coug-lomerates  and  the  extension  of  the  sand  flats  far  to  the  east  there 
was  a  tilting-  of  the  beds,  which  gave  them  a  slight  eastward  dip  and  deep- 
ened the  eastern  channel  so  tliat  the  eastern  current  was  strengthened  and 
the  slate-conglomerates  passed  by  a  broad  transgression  west  over  the  sands. 

ANALYSES. 

The  rock  of  the  Kibbe  quarry,  of  East  Longmeadow,  has  been  analyzed 
by  Prof  C.  F.  Chandler,  of  New  York;   that  of  the  Worcester  quarry  and 
of  the  Maynard  quarry  by  the  "Worcester  Polytechnic  Institute. 
Analysis  of  the  rocks  of  the  Kible  (I),  Worcester  {II),  and  Maynard  (III)  quarries. 


I. 

II. 

in. 

Silica                              . ...... -. 

Per  cent. 

81.38 

9.44 

3.54 
.76 
.11 
.28 

Per  cent. 

88.89 

5.95 

1.79 

.27 

Per  cent. 

79.38 

8.75 

2.43 

2.57 

Oxide  of  manganese                ......    ........   ... .   . 

Mao'nesl  a                                        ............ .. 

Alkalies                             _  ... ........ . 

.86 
1.83 

4.08 
2.79 

Carbonic  a;cid,  water,  and  loBS . ..--- ... 

4.49 

100. 00 

99.59 

100.00 

The  amount  of  alumina  shows  that  there  is  probably  considerable 
feldspar  in  the  rock,  and  that  some  part  of  the  loss  is  alkali. 

THE    GRANBY    TUFF,  OR    THE    DIABASE-TUFF. 

This  bed  is  the  most  distinct  geological  unit  of  the  series.  It  is  made 
up  of  diabase  ash,  lapilli,  and  bombs.  It  grows  finer  in  any  section  from 
bottom  to  top  and  from  west  to  east.  W  est  of  the  Connecticut  it  is  made 
up  of  coarse  material,  with  many  masses  as  large  as  one's  head.  South  of 
The  Notch  it  consists  of  fine  lapilli,  and  farther  east  it  is  a  consolidated  ash 
bed.  It  always  contains  some  granitic  material,  often  only  muscovite  scales. 
The  transition  from  sandstone  to  tuff  is  sudden,  and  the  tuff  rests  on  arkose 
from  the  east  end  to  the  river,  and  then  on  fucoidal  sandstone.  It  grad- 
uates upward  imperceptibly  into  the  fucoidal  sandstone,  and  while  the 
main  trap  sheets  made  no  impression  on  the  sediments,  the  tuff  furnished 
abundance  of  iron  and  lime  to  all  the  upper  beds.  It  is  described  in  detail 
in  Chapter  XIII,  in  connection  with  the  description  of  the  volcanic  rocks. 

MON  XXIX 24 


370  GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS, 

THE   CHICOPEE   SHALE,  OR   THE   CALCAREOUS   SHALE. 

All  the  bluffs  in  the  city  of  Holyoke,  especially  the  long  raih-oad  cut, 
are  made  up  of  a  gray  shale  which  varies  into  a  paper-thin  red  sandstone, 
in  which  rarely  a  bed  a  foot  thick  can  be  quarried.  It  always  effervesces 
abundantly  with  acid;  many  beds  are  full  of  nodular  concretions  of  clayey 
limestone,  and  at  times  these  coalesce,  cementing  thick  beds  of  the  clay 
into  water-lime. 

The  rod-shaped  concretions  which  have  been  called  fucoids  are  want- 
ing, but  all  the  marks  of  frequent  recession  of  the  water,  as  mud-cracks, 
raindrops,  and  ripjDle-marks,  are  present.  The  rock  abounds  in  casts  of 
gypsum  and  of  salt  crystals.  It  extends  from  Holyoke  southward,  occu- 
pying the  central  portion  of  the  basin,  and  is  bounded  on  either  side  by 
the  Longmeadow  sandstone. 

The  large  quantity  of  hematite  and  of  iron-  and  lime-carbonate  would 
seem  to  have  been  derived  from  the  subjacent  trap  and  trap-tuff. 

THE     CONTINUATION    OF    THE    STATE-LINE    FAULT    IN    A    CRUSHED    BAND    AT 
HOLYOKE  DAM,  AND  THE  SECONDARY  MINERALS  FOUND  IN  THE  FISSURES.' 

During  the  building  of  the  new  dam  at  Holyoke,  the  shales  of  the 
area  below  the  present  dam  were  accessible  for  a  long  time,  and  a  deep 
trench  was  blasted  from  the  foot  of  the  dam  halfway  to  the  bridge  below, 
which  exposed  an  exceptionally  crushed,  folded,  and  faulted  band  in  the 
shales  (fig.  23). 

The  section  begins  in  midstream  at  the  foot  of  the  dam  and  extends 
60  rods  east  toward  the  bridge.  For  11  rods  the  rock  is  a  red  sandstone  of 
medium  to  fine  grain,  which  runs  in  easy  undulations  and  has  a  slight  dip 
north,  or  from  the  observer.  A  compact  bed  of  different  color  from  that  of 
the  rest  indicates  a  fault  at  the  middle  and  end  of  this  part  of  the  section. 
This  is  followed  by  a  fine,  brittle,  calcareous  shale — a  slightly  indurated 
mud  rock,  at  times  massive,  at  times  banded,  generally  dark-gray,  but  often 
of  a  bright  red;  some  of  the  bands  are  a  buff  water-lime.  This  is  strongly 
folded,  jointed,  and  contorted,  and  in  several  places  one  or  two  rods  wide 
crushed  completely,  so  that  all  structure  is  gone,  and  after  being  thrown 
out  on  the  bank  the  rock  slakes  under  the  influence  of  the  weather  and 
crumbles  to  powder  in  a  few  days. 

'  For  further  discussion  of  State-line  fault,  see  the  section  "The  Holyoke  Sheet,"  p.  446. 


OKUSUED  BAND  AT  flOLYOKE  DAM. 


371 


3 


i 


At  the  east  end  of  the  section  the  red  sandstone  reappears  for  a  few 
rods,  with  the  normal  low  dip  to  the  east  and  no  twisting  of  the  beds 

On  examining  my  maps  I  found  that  the  State-line  fault, 
which  I  had  located  where  it  crossed  the  two  trap  ranges, 
and  had  not  been  able  to  follow  farther  north  beneath  the 
great  sand  plains  of  Holyoke,  would  cross  the  Connecticut 
just  at  the  place  of  the  section.  I  have  therefore  prolonged 
this  fault  so  as  to  make  it  include  the  central  shale  of  the 
section,  and  consider  this  an  area  of  crushing  at  the  passage 
of  the  fault.  The  throw  of  the  fault  does  not  seem  to  be 
great,  and  it  is  probable  that  the  shale  is  an  upper  member 
dropped  in  between  the  sandstone  beds  and  strongly  crushed. 

The  shales  contain  impressions  of  hopper-shaped  salt 
crystals,  cubical  cavities,  variously  distorted,  from  which  salt 
has  been  removed,  and  angular  cavities  3  inches  by  ^  inch 
in  cross-section  and  1  inch  deep,  from  which  some  mineral, 
probably  barite,  has  been  removed.  Many  shrinkage  cracks, 
often  forming  complex  networks  and  broad  stellate  forms, 
are  filled  with  white  calcite. 

At  a  much  later  time  the  abundant  fissures,  formed  by 
the  crushing  of  the  rock,  were  filled  by  a  more  complex 
series  of  minerals.  The  oldest  is  siderite,  which  coats  broad 
surfaces  with  fine  crystals  often  a  third  of  an  inch  across, 
ranging  in  color  from  a  yellowish  gray  to  a  rich  reddish 
yellow,  and  as  they  have  the  faces  R  and  co  R  2  equally 
developed  they  simulate  dodecahedi-a  and  suggest  cinnamon 
garnets.  Before  the  completion  of  their  growth  flat  blades 
of  gypsum  formed  upon  them,  which  have  since  been 
removed.  They  were  followed  by  a  curious  acicular  growth 
of  barite — parallel  groups  of  straight,  doubly  serrate  needles 
formed  of  minute  rhombic  prisms  (OP,  coP)  just  touching 
by  the  acute  angles  and  having  the  axis  b  common.  These 
are  superficially  inclosed  in  the  siderite  and  project  from  it 
in  a  common  direction. 

The  specimens  are  beautifully  frosted  by  a  growth  of  small  white 
calcites,  R  3,  oo  R,  -fR,  — 2  R,  with  rounded  apex  or  coated  by  a  layer  of 


p. 


i 


r^ 


372  GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

brittle  anthracite  whose  rounded  surfaces  indicate  that  it  came  into  the 
fissure  as  a  bitumen,  but  which  gives  a  yellov*  flame  for  an  instant  only 
and  then  bums  with  extreme  slowness. 

This  is  often  coated  by  a  layer  of  pyrites  of  very  modem  growth. 
"Where  the  same  beds  are  crossed  by  the  Chicopee  River  the  red  shales 
contain  broad  seams  of  a  pink,  transversely  fibrous  calcite,  and  in  the  bed  of 
the  Westfield  River,  in  West  Springfield,  all  the  occurrences  detailed  above 
are  repeated  and  the  curious  salt  pseudomorphs  described  on  page  389 
are  also  found. 

THE  DIABASE. 

The  great  Deerfield  and  Solyoke  diabase  beds  and  the  posterior  or 
Talcott  bed  fall  into  this  series,  but  lie  partly  intercalated  in  each  of  the 
above  members  and  partly  on  their  borders.  They  are  described  in 
Chapter  XIII. 

The  series  of  newer  volcanic  cores,  of  which  the  Black  Rock  may  be 
taken  as  the  type,  close  the  list  of  Triassic  deposits.  They  are  specially 
described  near  the  end  of  Chapter  XIII. 

THE    FORMATIOK    OF    THE    BASIK   AND    THE    DISTRIBUTION"    OF    THE 
SEDIMENTS  BY  STRONG    TIDAL   CURRENTS. 

The  rocks  which  have  been  described  are  not  chronologically  succes- 
sive in  the  order  given,  or  in  any  order,  but  are  synchronous  facies,  depend- 
ent for  their  variety  on  the  varying  character  of  the  shore  rocks  from  which 
they  were  derived,  on  the  strength  and  direction  of  the  tidal  currents  by 
which  they  were  carried,  and  on  the  varying  distance  from  shore  and  the 
varying  depth  of  water  in  which  they  were  deposited.  The  last  is  a  most 
important  element.  Because  of  the  great  depth  of  the  western  portion  of 
the  basin  and  the  abundance  of  granite  along  the  western  shore,  the 
advancing  waters  may  have  begun  to  deposit  the  arkose  here  a  little  ear- 
lier than  the  other  varieties,  but  very  soon  must  have  come  in  contact 
with  the  argillites  and  schists  of  the  eastern  border,  and  the  development 
of  the  arkose  and  that  of  the  conglomerate  were  then  strictly  synchronous. 
As  the  waters  rose  and  attained  greater  width  the  central  portion  of 
the  basin  was  occupied  by  a  deposit  of  offshore  sands — the  Longmeadow 
or  fucoidal  sandstones — and  when  the  maximum  width  was  reached 
the  middle  portion  of  the  sandstones  sank  to  the  fine-grained  sand  and  mud 
beds  which  have  become  the  central  Chicopee  shales. 


FOEMATION  OF  THE  TKIASSIC  BASIN,  373 

The  coarser  beds  are  not  so  well  fitted  to  retain  marks  of  exposure,  but 
the  false  bedding  and  the  ripple-marking,  together  with  the  lack  of  indica- 
tions of  exposure,  convince  me  that  during  the  earlier  portions  of  the  Trias 
the  waters  were  deeper,  and  of  such  depth  as  to  render  the  strong  currents 
most  effective,  and  that  later  the  broad  basin  became  so  shallow  that  the 
currents  were  effective  only  where  concentrated  in  their  shoreward  portions, 
while  over  the  broad  central  and  shallower  flats,  regularly  abandoned  by 
the  tide,  conflicting  currents  carried  only  fine  material. 

An  inspection  of  the  detailed  geological  map  of  the  Appalachian  chain 
makes  it  very  plain  that  the  southward  trend  of  the  main  structure  lines 
across  New  England  must  have  made  a  great  sigmoid  curve  to  the  west  in 
sympathy  with  the  same  curves  in  the  more  western  chains  across  the  Mid- 
dle States,  and  that  a  great  post-Carboniferous  sinking  must  have  depressed 
an  extended  block  south  of  an  east- west  line  running  north  of  Long 
Island,  thus  producing  the  "  Rias  Coast"  ^  of  southern  New  England  and 
admitting  the  sea  into  the  deep  fjordlike  bay  of  the  Connecticut  River 
Trias.  The  development  of  the  fault  system  which  borders  this  bay  and  has 
produced  it  may  have  been  an  attendant  upon  the  larger  movement,  but  it 
is  quite  clear  that  the  depression  of  the  bottom  of  the  basin  was,  in  part  at 
least,  synchronous  with  the  accumulation  of  the  Triassic  sands,  and  in  part 
of  later  date. 

It  is  difficult  to  assign  the  coiTect  value  to  this  cause,  the  sinking 
of  the  bottom  of  the  basin,  as  another  valid  cause  is  recognizable  which 
worked  to  the  same  end,  namely,  the  great  Triassic  transgression.  While 
the  above  statements  present  the  true  explanation  of  the  formation  of  the 
Triassic  basin — that  it  is  a  narrow  fault-bounded  and  sunken  block — the 
presence  of  a  large  number  of  isolated  sandstone  and  conglomerate  masses 
along  the  Atlantic  Coast  indicates  a  genei'al  positive  motion  of  the  waters 
over  the  land  along  the  whole  coast — one  of  those  general  "transgressions" 
the  importance  of  which  has  been  so  ably  enforced  by  Suess — as  the  true 
explanation  of  the  gradual  advance  of  the  waters  into  the  basin. 

I  have  now  collected  abundant  evidence  that  the  waters  in  their  slow 
transgression  across  the  bottom  and  up  the  sides  of  the  basin  found  a 
great  store  of  material  for  their  work  in  the  results  of  the  secular  disinte- 

'  A  coast  line  which  truncates  mountain  chains  about  at  right  angles  to  their  trend:  Suess,  Das 
Antlitz  der  Erde. 


374  GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS 

gration  of  tlie  rocks  (as  insisted  upon  recently  by  Professor  Pumpelly  and 
applied  by  him  to  a  more  ancient  transgression)/  especially  the  vast  amount 
of  granitic  debris,  which  has  been  swept  into  its  place  so  rapidly  that, 
although  carried  many  miles  across  the  valley,  it  is  so  angular  that  it  seems 
to  be  still  at  the  base  of  the  granite  ledge  from  which  it  was  derived. 

I  have  been  further  led  to  look  with  some  hope  upon  the  theories  con- 
cerning former  high  tides  and  strong  tidal  currents  which  have  been  so 
eloquently  expounded  by  the  astronomer,  Sir  Robert  Ball,^  for  it  is  beyond 
question  that  the  sediments  were  spread  by  tidal  currents  which  passed 
north  up  the  west  side  of  the  valley  and  down  the  east  side,  and  with  a 
force  greater  than  I  can  find  anywhere  described  for  modem  cuirents. 
The  proof  of  this  is  presented  here  in  abstract,  but  many  details  are  given 
in  the  description  of  the  different  rocks  in  the  last  chapter. 

Along  the  middle  portion  of  the  western  border-lands  of  the  Triassic 
basin  is  a  very  great  development  of  granites,  abundantly  muscovitic,  and 
the  schists  down  to  the  southern  line  abound  in  these  dikes,  which  plainly 
extend  eastward  far  beneath  the  border  of  the  Trias.  Now,  all  along  this 
line  the  Trias  is  made  up  at  the  shore-line  of  a  granitic  conglomerate  which, 
as  it  extends  far  out  into  the  valley  and  up  in  the  series,  graduates  through 
coarse  to  fine  arkose. 

In  the  northern  half  of  the  State  the  western  border-country  is  of 
black  schists  and  argillites,  but  the  arkose  sweeps  up  along  this  shore  for 
more  than  20  miles,  scarcely  darkened  by  any  admixture  of  the  black 
schists,  but  where  it  is  coarse  containing  many  large,  well-rounded  pebbles 
of  the  vein  quartz  from  the  schists.  Here  it  is  plain  that  the  immediate 
shore  wash  has  rounded  the  quartz  pebbles,  and  that  they  have  then  been 
carried  outward  by  the  undertow  and  forward  diagonally  by  the  sweep  of 
the  tidal  current,  while  the  mass  of  the  material  came  from  much  farther 
south. 

The  same  thing  is  clear  along  the  eastern  side  of  the  valley.  The 
materials  derived  from  each  of  the  rocks  that  formed  the  ancient  shore  are 
carried  far  south  of  the  area  occupied  by  the  respective  rock.  At  the 
north  end  the  peculiar  crystalline  rocks  of  the  Northfield  hills  form 
the   slate-conglomerates    at   their   foot  and  are   carried   far   south.      And 

'Secular  rock  disintegration:  Am.  Jour.  Sci.,  3d  series,  Vol.  XVII,  1879,  p.  133.  The  relation 
of  secular  rock  disintegration  to  certain  transitional  crystalline  schists :  Bull.  Geol.  Soc.  America, 
Vol.  II,  1891,  p.  209. 

■^  A  glimpse  through  the  corridors  of  time:  Nature,  Vol.  XXV,  p.  79. 


FORMATION  OF  THE  TRIASSIO  BASIN. 


37 


y 


thoy,  with  the  equally  peculiar  rocks  which  are  disclosed  by  erosion  in 
the  midst  of  the  conglomerates  of  Mount  Toby,  are  carried  south  over  the 
granites  of  the  eastern  shore,  and  the  arkose  derived  from  these  granites  at 
last  takes  their  place  and  is  itself  continued  south  at  the  foot  of  the  slate 
bluffs  of  Wilbraham,  where  it  slowly  gives  place  to  a  slate-conglomerate. 
Where  the  basin  is  narrow  these  two  rocks — the  arkose  on  the  west  and  the 
conglomerate  on  the  east — meet  and  blend  in  an  interdigitating  boundary. 
When  the  basin  widens  they  separate  to  include  broad  areas  of  sandstones 
and  shales,  representing  the  sand  and  mud  flats  which  intervened  between 
the  strong  current  which  moved  up  the  west  side  and  that  which  passed 
down  the  east  side  of  the  basin. 

I  have  elsewhere  (p.  353)  described  the  Mount  Toby  conglomerate  as 
resting  upon  a  pedestal  of  crystalline  rocks  whose  surface  is  nearly  400 
feet  above  the  sea.  This  pedestal  is  continued  south  as  the  great  ridge  upon 
which  Amherst  is  built.  The  presence  of  this  ridge  and  the  consequent 
shallowness  of  the  waters  explain  the  fact  that  the  arkose  extending  south 
from  the  ridge  expands  entirely  across  the  valley  and  contains  from  its 
eastern  border  clear  to  the  Mount  Tom  station  in  the  center  of  the  basin 
angular  pebbles  of  granite,  often  as  large  as  one's  fist. 

Wherever  I  have  examined  the  cross-bedding  it  tells  the  same  story 
as  to  the  direction  of  the  currents;  as  in  the  bluffs  of  Mount  Tom,  and 
especially  in  a  fine  island  of  arkose  in  the  northwest  bend  of  the  Deerfield 
River  (which  is  interesting  as  having  more  than  sixty  potholes  cut  in  its 
surface  by  the  strong  high-water  current  of  the  present  river,  which  passes 
over  it),  where  the  beautiful  cross-bedding  is  plainly  directed  northerly. 

President  Hitchcock  presents  the  matured  results  of  his  long  studies 
of  the  Trias  in  the  introduction  to  the  Ichnology  of  Massachusetts  (1857), 
wherein  he  gives  the  details  of  four  sections  across  the  sandstones,  in  which 
he  obtained  the  following  thickness: 


Thickness  of  the  Triassic  sandstones  at  different  localities. 

Locality. 

Below  the 
trap. 

Above  the 
trap. 

Turners  Falls .         .                            

7,788 
5,283 
5,115 
8,128 

4,190 

1,584 

8,102 

11,  500 

Mount  Toby 

Mount  Tom 

376       GEOLOGY  OF  OLD  HAMPSHIEE  OOUNTT,  MASS. 

He  was  not  satisfied  with  these  numbers,  as  they  seemed  excessive; 
and  he  gives  consideration  to  original  deposition  on  an  incline  and  to  fault- 
ing as  explanations,  and  rejects  both,  effectively  disproving  the  first  and 
remarking  concerning  the  second  that  he  had  been  unable  to  find  any  con- 
siderable faults,  such  as  the  theory  would  demand.  Accordingly  he  consid- 
ered the  general  easterly  dip  to  indicate  that  there  was  a  uniform  progression 
from  older  to  newer  beds  in  passing  from  west  to  east  and  made  a  threefold 
division — (1)  the  sandstones  below  the  trap,  (2)  the  sandstones  above  the 
trap,  and  (3)  the  conglomerates  of  Mount  Toby,  the  latter  being  the  newer. 

More  favorable  exposures  and  more  detailed  mapping  have  revealed 
many  faults,  and  I  feel  sure  that  many  more  remain  concealed. 

Along  the  eastern  side  of  Mount  Toby  the  coarse  conglomerate  rests 
in  normal  unconformity  upon  the  old  quartzite,  and  instead  of  being  newer 
than  the  fine-grained  sandstones  (the  distinctions  I  have  made  of  arkose  and 
red  fucoidal  sandstone  agree  in  the  main,  though  not  exactly,  with  the  above 
distinctions,  sandstone  below  the  trap  and  sandstone  above  the  trap),  it  is 
certainly  older  than  these,  and,  as  an  eastern-shore  deposit,  is  to  be  placed 
parallel  with  the  arkose  which  forms  the  shore  deposit  along  the  western 
side  of  the  estuary.  As  I  have  indicated  elsewhere  that  the  waters  spread 
over  this  portion  of  the  basin  somewhat  after  the  time  of  their  advent  in  the 
western  portion  of  the  basin,  I  should  not  place  them  parallel  to  the  base  of 
the  arkose  on  the  west,  but  rather  to  its  middle  and  upper  portions,  and 
should  place  the  main  continuous  mass  of  the  red  sandstones  and  shales 
which,  beginning  in  South  Hadley,  extend  broadly  southward  in  the  central 
portion  of  the  basin  as  in  pai't  later  than  both.  They  are  largely  the  tidal 
mud  flats  of  a  shoaled-up  and  contracted  estuary  which  must  have  had  high 
tides  like  the  Bay  of  Fundy. 

The  dips  are  certainly  for  the  most  part  easterly,  but  this  is  commonly 
overstated.  Across  Hatfield  they  are  largely  westerly.  In  Mount  Toby 
they  are  nearly  horizontal.  East  of  Turners  Falls  and  in  the  Holyoke 
range  they  swing  round  to  south.  In  Hampden  County  they  are  very  low 
and  rarely  observable  in  the  eastern  portion.  With  these  dips  and  with  the 
repeated  monoclinal  faulting  the  boundaries,  if  we  could  draw  them  accu- 
rately, would  often  be  sharply  serrate,  but  hindered  by  the  uniform  char- 
acter of  the  rocks  of  the  series,  and  more  by  the  thick  cover  of  till,  one 
can  di'aw  only  approximate  boundaries. 


FORMATION  OF  THE  TKIASSIC  BASIN.  377 

I  liave  l)een  greatly  interested  in  the  hypothesis  which  has  been 
advanced  and  expounded  with  so  much  acuteness  by  Prof.  W.  M.  Davis^ 
in  explanation  of  the  nionocliual  faulting,  and  applied  so  full}^  to  the  south- 
ward extension  of  this  area  across  Connecticut,  and  I  have  permitted  myself 
to  be  guided  by  it  as  far  as  possible.  This  has  been,  however,  rather  per- 
missive than  compulsorjr  in  this  region,  for,  as  just  seen,  the  easterly  dips  are 
only  slightly  in  the  ascendency.  All  the  strongest  dips  are  to  the  south,  as 
in  the  Holyoke  range,  in  Gill  and  northern  Montague,  or  northwest  in 
central  Montague.  In  several  cases  submerged  peaks  and  bosses  of  crys- 
talline rocks  have  thrown  off  the  sandstones  in  various  directions  and  have 
plainly  acted  rather  as  resistant  masses  against  which  the  sandstones  have 
been  crowded  irregularly  than  as  masses  whose  own  deeja-seated  compres- 
sion has  produced  a  monoclinal  faulting  in  which  the  sandstones  have  pas- 
sively shared.  Thus  at  the  mouth  of  Millers  River  the  rocks  have  been 
ci'ushed  and  faulted  against  a  great  mass  of  most  rigid  quartzite,  and  dip 
strongly  west,  and  a  little  farther  west  change  suddenly  to  high  south  dips, 
and  to  the  west  of  Montague  village  the  great  mass  of  uncovered  gneissoid 
conglomerate  throws  off  the  sandstones  to  the  northeast.  It  would  thus 
seem  that  in  all  its  northern  portion  the  valley  is  too  narrow  and  tortuous 
and  its  bottom  too  irregular  and  too  much  broken  through  by  later  intrusive 
plugs  of  trap  to  allow  of  the  regular  development  of  this  structure.  The 
southern,  broader  portion  of  the  valley  in  Massachusetts  is  too  much  covered 
to  exhibit  fully  the  system  of  the  faults. 

At  the  north  end  of  the  basin  the  boundary  extending  southwestward 
from  the  Connecticut  is  plainly  a  boundary  of  erosion,  and  the  conglomer- 
ates extended  formerly  muclx  farther  than  at  present.  Indeed,  it  leaves  the 
impression  that  the  basin  was  a  strait,  extending  northward  into  another  sea. 

An  inspection  of  the  map  will  show  that  the  whole  width  of  the  Trias 
across  the  north  of  Grill  is  of  conglomerate,  equally  divided  between  the 
arkose  on  the  west  and  the  slate-conglomerate  on  the  east.  The  boundary 
is  a  narrow,  transitional  band,  rather  than  a  line,  but  is  very  distinct.  From 
Bernardston  across  to  the  boundary  the  rock  is  pure  granitic  ddbris;  near 
this  line  slate  pebbles  begin  to  appear,  rounded  and  far-traveled,  and  soon 
the   finer   material    comes   to    be    also  wholly  of  comminuted    slate    and 

lAm.  Jour.  Sci.,  3(1  series,  Vol.  XXIV,  p.  347;  Vol.  XXXII,  p.  342.  Bull.  Mus.  Comp.  Zool. 
Harvard  Coll.,  geol.  series,  Vol.  II,  p.  99. 


878  GEOLOGY  OP  OLD  HAMPSHIEE  COUNTY,  MASS. 

quartz,  and  continues  thus  across  to  the  river.  The  granitic  material  on 
the  west  has  been  brought  from  20  miles  south,  the  slaty  material  from 
Vernon  and  Northfield  to  the  northeast,  and  the  two  currents  pass  each 
other  well  established,  with  plenty  of  room  to  move  in,  and  do  not  show 
any  indication  that  they  are  located  near  the  head  of  a  narrow  bay. 

The  behavior  of  the  great  overflow  trap  sheets  is  instructive  as  indicating 
the  character  of  the  bottom  over  an  extended  area  at  a  given  time.  The 
Deerfield  bed  is  an  overflow,  as  is  proved  by  the  beautiful  ropy  surface  at 
Turners  Falls.  That  it  flowed  over  the  muddy  bottom  of  the  bay  is  indi- 
cated by  the  kneading  together  of  trap  and  shale  in  Greenfield  (see  p.  419). 
It  rests  on  the  Mount  Toby  conglomerate  from  Gill  Center  nearly  to  Fall 
River,  then  on  fucoidal  sandstone  and  shale  to  Deei-field,  then  on  arkose 
to  the  Connecticut,  and  on  the  Mount  Toby  conglomerate  to  the  south 
end  of  Mount  Toby.  It  had  little  influence  upon  the  later  rocks,  and  is 
covered  by  the  same  rocks  as  those  which  lie  beneath  it,  except  that  the 
boundary  of  the  fucoidal  sandstone  and  the  Mount  Toby  conglomerate  is 
shifted  to  the  north  by  an  amount  equivalent  to  the  thickness  of  the  trap. 

The  same  is  true  of  the  Holyoke  bed.  The  same  buff  arkose  that  pre- 
cedes its  advent  also  rests  upon  it,  and  does  not  receive  the  smallest  influence 
from  the  abundant  iron  in  the  trap,  as  it  was  immediately  covered  by  the 
strong  currents.  It  continues  to  rest  on  the  arkose  to  Holyoke,  and  from 
there  to  the  south  line  of  the  State  rests  upon  the  fucoidal  sandstone  and 
the  shale.  All  these  rock  types  thus  formed  portions  of  the  bottom  of  the 
basin  at  the  same  time. 

The  shallowing  of  the  basin  effected  by  the  outflow  of  the  great  mass 
of  trap  made  itself  manifest  in  the  transfer  of  the  boundary  of  the  arkose 
and  sandstone  far  to  the  north.  That  is,  it  shallowed  the  waters  so  that 
along  the  central  axis  of  the  valley  the  finer-grained  sandstones  character- 
istic of  the  shallower  central  area  extended  much  farther  north.  This 
strengthens  the  impression  that  one  gets  from  the  signs  of  repeated 
emergence  from  the  water,  so  abundant  in  the  sandstones,  and  their  absence 
from  the  arkose,  viz,  that  the  sandstone  was  deposited  in  shallower  water 
and  laid  bare  at  low  tide.  That  the  arkose  and  calcareous  shales  were 
deposited  at  the  same  time  is  further  shown  by  the  fact  that  from  Titans 
Pier,  where  the  Holyoke  trap  sheet  crosses  the  Connecticut,  nearly  to  the 
Westfield  River,  about  ten  miles,  the  trap,  which  here  everywhere  rests 


FOOTTKACKS  AND  TEAP  SHEETS.  379 

cHrecth'  on  the  coarse  arkose,  is  filled  with  fragments  of  the  fine-grained 
shales  and  dove-colored  limestones  Avhich  were  in  place  as  part  of  the  bot- 
tom far  to  the  east  or  southeast.  This  shows  that  the  fissure  was  situated 
east  or  southeast  of  the  present  outcrop,  and  that  the  trap  broke  through 
and  flowed  out,  first  over  the  mud  flats  and  then  over  the  coarse  granitic 
debris  lying  westward.  The  greater  thickness  of  the  trap  sheet  in  just  this 
portion  of  its  length,  viz,  in  Mount  Tom,  may  be  because  the  trap  sheet 
extended  into  the  deeper  shoreward  portion  of  the  basin — that  occupied 
by  the  western,  northward-moving  current. 

TETE  POSSIBLE  CONISTECTION  OF  THE  FOOT-TKACKS  WITH  THE  TRAP 

SHEETS. 

It  is  furthermore  interesting  to  observe  that  all  the  famous  localities  of 
tracks  are  far  out  in  the  center  of  the  ancient  bay,  in  sandstones  that  rest 
directly  upon  the  back  of  the  broad  trap  sheets,  and  not  very  high  up  above 
the  upper  surface  of  the  trap. 

Above  both  the  Deerfield  and  the  Holyoke  trap  sheet  the  area  within 
which  these  tracks  occur  is  approximately  identical  with  the  area  overspread 
by  the  trap  sheet,  and  it  seems  to  me  quite  probable  that  the  shallowing  of 
those  broad  central  areas  of  the  bay  300  to  400  feet  by  the  great  trap  sheets 
may  have  produced  the  peculiar  surfaces  just  between  tides,  on  whose  sand 
and  mud  flats  the  reptiles  walked  and  the  raindrops  made  their  marks.  The 
iron  which  was  soon  set  free  from  the  decomposing  lavas  below  permeated 
the  muds  and,  besides  giving  them  their  red  color,  cemented  them  with 
unusual  rapidity,  and  so  favored  the  very  remarkable  preservation  of  the 
tracks,  as  the  preparation  of  the  broad  central  intertidal  mud  flats  favored 
their  production. 

There  are  more  than  20,000  tracks  in  the  Amherst  collection,  perhaps 
as  many  more  in  that  of  Yale,  and  again  as  many  more  in  other  collections, 
and  it  is  hard  to  say  how  many  have  been  destroyed  for  every  one  in  the 
collections.  There  is,  therefore,  something  quite  exceptional  to  be  explained 
in  the  vast  number  of  these  tracks  which  are  found  in  this  very  limited 
space.  There  is  a  slight  possibility  that  the  heat  of  these  great  trap  sheets 
may  have  promoted  rapid  consolidation  of  the  sand  layers  by  which  they 
were  quickly  covered. 


V 


380^ 


GEOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 


ARTESIAN   WELLS. 


WELL   AT   TURNERS   PALLS. 


Artesian  well  of  Montague  Paper  Company,  Turners  Falls,  just  west 
of  the  south  end  of  the  dam.  Samples  at  Amherst  College.  For  analysis 
of  vwater  see  Chapter  XXI.  The  rock  lies  very  near  the  surface  and  25 
feet  below  the  top  of  the  dam.  The  figures  indicate  distance  in  feet  from 
the  surface  of  the  rock. 

Record  of  artesian-well  boring  at  Turners  Falls. 


Kind  of  rock. 


Gray  sandstone,  grains  1™"";  quartz  abundant;  feldspar,  musoovite, 
biotite,  rare 

Gray,  shaly  muscovite-aandstone  much  finer  than  at  15,  but  mixed  with 
the  latter ;  nohcalcareous , 

Same;  little  darker  and  finer 

White  sandstone,  grains  1  to  4™"' ;  quartz,  muscovlte,  biotite 

Same;  grains^""".     "  Small  vein  of  water  here" 

Brownish-gray  sandstone;  musoovite  and  biotite  abundant;  "1  foot 
thick" , 

Gray,  micaceous,  shaly  sandstone ;  "  1  foot  thick  " 

Same;  "slate,  quite  soft" 

Dark-gray,  micaceous,  shaly  sandstone 

Brownish-gray,  micaceous,  shaly  sandstone 

Light-gray,  micaceous,  shaly  sandstone ;  "  struck  water  here  " 

Gray,  micaceous  quartz-sandstone,  grains  1  to  4""" 

Gray,  shaly  sandstone 

Same 

Red,  micaceous  sandstone,  fine-grained , 

Dark-red,  micaceous  sandstone,  fine-grained , 

Gray  quartz-sandstone,  grains  1  to  3"" ;  angular 

Brownish-black,  pyritous  shale 

Dark-gray  shale 

Light-gray  shale , 

White  quartz-sandstone,  grains  1  to  2"ioi  |  little  musoovite 

Same 

Buff  quartz- sandstone,  grains  1  to  6""";  well  rounded;  "  water  here ". . 

Clear-gray  quartz-musoovite-sandstone,  grains  1  to  6""" , 

Light-chocolate  quartz-musoovite-sandstone,  grains  1  to  6"" 

Dark-brown  quartz-muscovite-sandstone,  grains  1  to  6"™ ;  shaly 

Same 

Same 

Same 


15 

18 
23 
24 
26 

32 
33 

34 

50 

54 

56 

60 

66 

68 

72 

80 

85 

94 

106 

110 

120 

125 

133 

140 

150 

200 

225 

260 

275 


ARTESIAN  WELLS. 
Record  of  artesian-well  boring  at  Turners  Falls — Continued. 


381 


Kind  of  rock. 


Same 

Saiiio 

Bright  brick-red  quartz-muscovite-sandstone,  grains  1  to  6""";  shaly... 

Dark-brown,  shaly  sandstone,  very  micaceous 

Bright- red,  shaly  quartz-muscovite-sandstone,  grains  1  to  6"'™ 

Same 

Coarse  quartz-sandstone,  grains  3  to  5™"" 

Bright-red  quartz-muscovite-sandstone,  grains  1  to  2'""" 

Same 

Pale-green  chloritized  diabase,  larger  lath-shaped  twinned  plagioclase 
grains  1  by  1  to  3"'™ ;  augite  wholly  changed  to  chlorite ;  magnetite 
octahedra.  The  microscope  shows  much  feldspar  in  two  generations ; 
little  pyroxene - 

Same.  The  pyroxene  shows  under  the  microscope  nearly  colorless 
center  and  good  cleavage;  yellow-green  border  and  poor  cleavage. . 

Same 

Coarse-grained,  light  greenish-gray  diabase,  copper-tinged;  many 
grouped  magnetite  octahedra.  Under  the  microscope  the  pyroxene 
is  fresh,  green,  and  much  twinned 

Dark-red  quartz-muscovite-sandstone,  grains  1  to  6""";  shaly 

Light-gray  quartz-mnscovite-sandstoue,  grains  1  to  6'"™ ;  shaly 

Red  quartz-muscovite-sandstone, grains  1  to 6'"";  shaly 

Light-gray  quartz-sandstone,  grains  J""' ;  well  rounded 

Brown-gray  quartz-muscovite-sandstone,  grains  1  to  2™™ 

Dark-red  quartz-muscovite-sandstone,  grains  1  to  4™"" 

Same 

Gray  quartz-muscovite-sand  stone,  grains  1  to  5"°™ 

Eeddish-gray  quartz-muscovite-sandstone,  grains  1  to  5™™ 

Coarse,  buff  quartz-muscovite-sandstone,  grains  1  to  5°"" 

Dark-red  quartz-muscovite-sandstone,  grains  1  to  5""' 

Eed,  shaly  quartz-muscovite-sandstone,  grains  1  to  6™"' 


Feet. 


290 
320 
340 
360 
390 
400 
420 
440 
460 


560 

610 
617 


640 
670 
690 
700 
705 
708 
710 
738 
795 
800 
810 
865 
875 


"WELL  AT   SOUTH   HADLET. 


Artesian  well  at  Mount  Holyoke  College,  South  Hadley.  Samples  at 
Mount  Holyoke  and  Amherst  colleges.  Samples  all  calcareous,  very  finely 
pulverized,  so  that  structure  could  be  only  partly  made  out. 


382  GEOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 

Record  of  artesian-well  boring  at  South  Hadley. 


Kind  of  rock. 


Fine  buff  sand "| 

Same >  Terrace  sands 

Very  fine  bufl'  sand. . .  J 

Rather  fine-grained,  light-red,  micaceous  sandstone,  muscovitic 

Same,  but  much  mixed  with  sand 

Light-red,  fine-grained,  muscovitic  sandstone 

Same 

Same 

Red,  fine-grained,  muscovitic  sandstone 

Dark-gray,  shaly,  muscovitic  sandstone 

Red,  very  fine-grained,  muscovitic  sandstone 

Brick-red,  very  fine-grained,  muscovitic  sandstone 

Same 

Same 

Gray,  very  fine-grained,  muscovitic  sandstone 

Dark-gray  shale 

Same 

Brick-red  shale 

Brick-red,  shaly,  muscovitic  sandstone 

Same 

Brownish-gray,  shaly  sandstone 

Dark-gray,  shaly  sandstone 

Same 

Same 

Pale-buff,  shaly  sandstone , 

Chocolate-colored,  fine-grained,  micaceous  sandstone , 

Like  260 , 

Light-gray,  fine-grained,  micaceous  sandstone 

Dark-gray  shale 

Same 

Same 

Reddish-gray,  fine-grained,  micaceous  sandstone 

Dark-gray,  fine-grained,  micaceous  sandstone 

Dark-gray  shale , 

Dark-gray,  fine-grained,  micaceous  sandstone 

Reddish-gray,  fine-grained,  micaceous  sandstone 

Brick-red,  fine-grained,  micaceous  sandstone 

Same 

Same 

Gray,  fine-grained,  micaceous  sandstone 

Light-gray,  fine-grained,  biotitic  sandstone 

Brick-red,  muscovitic  sandstone 

Same 


Feet. 


r  25 
30 
[  40 
50 
60 
70 
80 
90 
100 
110 
120 
130 
140 
150 
160 
170 
180 
190 
200 
210 
220 
230 
240 
250 
260 
270 
280 
290 
300 
310 
320 
330 
340 
350 
360 
370 
380 
400 
410 
420 
430 
440 
450 


ARTESIAN  WELLS. 


383 


WELL  AT  HOLYOKE. 

Artesian  well  of  Parsons  Paper  Company,  at  Holyoke;  near  west  end 
of  clam;  October,  1884.  E.  W.  Cliapin,  superintendent.  The  samples  in 
this  series  were  especially  clean,  and  the  method  of  boring  favored  the 
production  of  large  fragments.  All  the  samples  are  very  fine,  and  the 
distinction  di'awn  between  shale  and  sandstone  is  a  very  close  one.  The 
specimens  were  carefuU}'  bottled  and  labeled  with  depth  and  date,  and 
given  to  the  Amherst  College  cabinet  by  Mr.  Chapin. 

Record  of  artesian-well  boring  at  Holyol-e. 


Kiud  of  rock. 


Sand,  etc.  (not  reported) , 

Surface  of  rock :  a  dark-gray  shale,  black  when  wet;  much  efferves- 
cence with  HCl ;  melts  to  light-yellow  glass 

Same  black  shale ;  small  drusy  surfaces  of  calclte  crystals,  apparently 
E^  with  edges  out  by — 2Raud  apex  by  — JE 

Fine  sandstone,  dark  chocolate-brown,  slightly  calcareous,  micaceous. 

Same  sandstone,  slightly  redder  and  more  flaky ;  same  calcite  crusts  as 
102 


Same  very  fine,  micaceous  sandstone,  dark-gray ;  some  grains  colorless ; 
sandstone  with  biotite  and  muscovite  scales 

Fine,  light-gray,  micaceous  sandstone;  abundant  calcareous  cement... 

Mixture  of  132  and  150 ;  calcite  crusts 

Dark-gray  shale ;  calcareous,  pyritous  grains 

Fine-grained,  chocolate,  micaceous  sandstone,  a  little  coarser  than  any- 
thing preceding ;  calcareous 

Dark-gray,  highly  calcareous  shale;  silky,  white,  acicular  efflorescence 
on  some  grains 

Same  as  164 

Same  as  160 , 

Same  as  190,  but  more  calcareous;  like  the  finest-grained,  thin-bedded 
sandstones,  which  often  show  insect  tracks 

Same  as  200 

Mixture  of  215  and  230 

Bluish-black,  slightly  micaceous  shale ;  very  calcareous 

Dark-gray,  micaceous  and  pyritous  shale 

Fine,  black,  calcareous  shale 

Same  as  240 

Dark-gray,  calcareous  shale 

Dark-chocolate,  shaly  sandstone 

Mixture  of  260  and  gray,  shaly  sandstone 

Same  as  270 

Mixture  of  dark-  and  light-gray  shale;  many  grains  show  efflorescence 
of  iron 


Feet. 


85 

102 
113 

115 

130 
132 
140 
150 

160 

164 
176 
190 

200 
215 
223 
230 
235 
240 
244 
255 
260 
270 
280 

285 


384 


GEOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 
Record  of  artesian-well  boring  at  Holyohe — Continued. 


Kind  of  rock. 


Dark-gray  shale  mixed  with  red. 
Same 


Fine,  coal-black  shale :  calcareous  . 
Same 


Chocolate,  shaly  sandstone. 
Same 


Feet. 


Dark-gray  shale. 
Same 


Bright-chocolate  shale. 
Same 


Dark-gray  shale 

Black  shale 

Light-gray,  calcareous  shale 

Dark-gray,  calcareous  shale 

Dark-chocolate,  iiue-grained  sandstone. 
Same 


Same ;  more  micaceous 

Black  shale 

Gray  shale 

Dark-gray  shale  with  layer  of  light-buff,  highly  calcareous  sandstone.. 

Dark-chocolate,  shaly  sandstone 

Same ;  micaceous 

Dark-gray  shale  with  admixture  of  475 

Dark-gray  shale ;  layers  of  fine-grained,  light-gray,  micaceous  sandstone. 

Dark-gray  shale ;  micaceous  and  only  slightly  calcareous 

Reddish- gray,  fine-grained,  shaly  sandstone 

Chocolate-colored,  fine-grained,  muscovitic  sandstone 


290 
300 
308 
318 
330 
338 
347 
355 
360 
365 
375 
380 
385 
390 
400 
408 
420 
435 
440 
460 
472 
475 
485 
490 
500 
505 
510 


Parsons  Paper  Company,  Holyoke,  Mass.     A  separate  partial  series 

from  the  same  well  as  the  last.     Samples  deposited  in  collection  at  Amherst 

College. 

Record  of  artesian-well  boring  at  Holyohe. 


Kind  of  rock. 


Red-brown,  fine-grained,  marly  sandstone,  very  ferruginous 

Black  shale 

Very  coarse,  rusty  sandstone 

Coarse,  dark  sandstone 

Same,  granitic 

Black  shale 

Same 

Dark-brown  sandstone 


Feet. 


250 
365 
400 
420 
425 
435 
445 
455 


ARTESIAN  WELLS. 
Record  of  artesian-well  boring  at  Holyoke — Continued. 


385 


Kiud  of  rook. 


Diirk-l>rown  sandstone  

Same,  granitic 

Ferruginons  marl 

DarU-brown  sandstone 

Same,  coarse  gneiss  grains 

Black,  shaly  sandstone 

Darli-gray,  shaly  sandstone 

Brown  sandstone , 

Dark  brown-gray,  marly  sandstone 

Brown  sandstone 

Coarse,  rusty,  granitic  sandstone.. 


Feot. 

460 
480 
490 
500 
530 
565 
570 
590 
615 
645 
685 


WELL  AT  NORTHAMPTON. 

Nortliampton,  at  Belding's  silk  mill,  south  of  the  railroad  station.  Com- 
menced in  1885.  Depth,  3,700  feet;  mouth  of  well,  125  feet  above  sea 
level.  In  New  Red  sandstone.  Samples  furnished  by  the  borers  of  the 
well  and  deposited  in  the  Amherst  College  collection. 

Record  of  artesian-well  boring  at  Northampton. 
[Abbreviations:  q,  quartz;  f,  feldspar;  m,  muscovite;  b,  biotite;  g,  garnet.] 


Kind  of  rock. 


Sand 

Clay 

Red  sand  (probably  till) 

Red  sandstone,  borings 

Coarse,  buff  sand,  white  to  amethystine  quartz,  flesh- 
colored  feldspar  grain 

Similar,  but  finer  and  more  rounded  grains 

Same 


Same ;  few  scales  muscovite  and  hornblende 
Same 


Same ;  many  grains  deep  red-brown  from  rust  covering, 
which  has  been  usually  worn  off  by  the  attrition  of  the 
driU 

Very  fine,  buff  sand,  quartz,  orthoclase,  and  abundant 
muscovite  scales 

Like  730 

Same 


Buff  sands,  quartz,  feldspar,  little  muscovite. 


Average 

grain,  in 

millimeters. 


itoli 

itoli 
itoli 


4  toll 
i  to  li 


i 


Feet. 


0 
140 
150 
535 

682 
692 
710 
730 
750 


780 

910 
930 
950 
970 


MON   XXIX- 


-25 


386  GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

Record  of  artesian-well  boring  at  Northam'pton — Continued. 
[Abbreviations:  q,  quartz;  f,  feldspar;  m,  muscovite;  b,  biotite;  g,  garnet.] 


Kind  of  rock. 


Buff  sands,  quartz,  feldspar,  little  muscovite 

Same 

Finer,  darker-brown,  much  mica 

Coarser,  light-buff,  granitic,  q.  f.  m 

Same,  q. f. m.b 

Same 

Same 

Same 

Same 

Light-buff,  granitic,  q.  f.  m.  b 

Same 

Same 

Fine,  light-buff,  granitic,  q.  f.  m.  b 

Fine,  light-buff,  granitic,  q.  f.  m.  b. ;  coal 

Light-buff,  granitic,  q.  f.  m.  b 

Same 

Same 

Fine,  light-buff,  granitic,  q.  f.  m.b 

Same 

Same 

Same 

Same 

Same 

Same 

Same 

Same 

Medium,  buff  sand,  q.  f.  m 

Medium,  buff  sand,  q.  f.  m. ;  few  worn  grains  black  slate 

Same 

Medium,  buff  sand,  q.  f.  m. ;  white  slate 

Same 

Medium,  buff  sand,  q.  f.  m. ;  black  slate 

Same 

Same 

Coarse,  buff  sand,  q.  f.  m. ;  black  slate 

Medium,  buff  sand,  q.  f.  m. ;  garnet,  slate 

Medium,  buff  sand,  q.  f.  m. ;  slate 

Medium,  buff  sand,  q .  f.  m.  b. ;  slate 

Same 

Medium,  buff  sand,  q.  f.  m.  b. ;  slate  trace 

Same 


Average 

grain, in 

millimeters. 

Feet. 

1 

990 

1 

1,010 

i 

1,030 

Uto2 

1,050 

Uto2 

1,070 

lito2 

1,090 

itoli 

1,110 

■itol* 

1,130 

|tol| 

1,130 

1 

1,170 

1 

1,190 

1 

1,210 

* 

1,230 

i 

1,250 

1 

1,270 

i 

1,310 

itol 

1,330 

i 

1,350 

ito2 

1,370 

*to2 

1,390 

itol 

1,420 

*tol 

1,440 

+  to2 

1,460 

ito2 

1,490 

ito2 

1,510 

ito2 

1,530 

itol 

1,550 

itol 

1,570 

itol 

1,590 

itol 

1,610 

Itol 

1,630 

itol 

1,650 

Itol 

1,670 

itol 

1,690 

lto3 

1,695 

itol 

1,710 

•itol 

1,730 

itol 

1,750 

itol 

1,770 

itol 

1,790 

itol 

1,810 

AKTESIAN  WELLS, 

Record  of  artesian-well  boring  at  Northampton — Continued. 
[Abbreviatious :  q,  quartz;  f,  feldspar;  in,  musoovite;  b,  biotite;  g,  garnet.] 


387 


Kind  of  rock. 


Meiiium,  bnflf  sand,  q.f.  m.  b. ;  garnet 

Medium,  buff  sand,  q.  f.  m.  b. ;  garnet,  slate  trace 

Same 

Same 

Medium,  buft' sand,  q.f.  m.  b. ;  slate  trace 

Same 

Same 

Same 

Same 

Same 

Same 

Medium,  buff  sand,  q.  f.  m.  b. ;  magnetite 

Medium,  buff  sand,  q.  f.  m.  b. ;  slate  trace 

Same 

Same 

Same 

Same 

Same 

Same 

Same 

Same 

Same 

Same 

Same 

Same 

Same 

Same 

Same 

Same 

Same 

Same 

Same 

Same 

Same 

Same 

Same 

Medium,  buff  sand,  q.  f.  m 

Same 

Same 

Coarse,  brown  sand,  q.  f.  m 

Same 


Average 

jE^rain,  in 

millimeteTs. 


itol 
Itol 
itol 
Itol 
itol 
I  to  2 
ito2 
I  to  2 
ito2 
I  to  2 
itol 
itol 
itol 
itol 
itol 
itol 
itol 
itol 
itol 
itol 
itol 
itol 
itol 
itol 
itol 
itol 
itol 
itol 
itol 
itol 
ito  1 
itol 
itol 
itol 
itol 
itol 
itol 
itol 
itol 
1  to5 
1    to3 


Feet. 


830 
850 
870 
900 
920 
940 
960 
980 
020 
030 
040 
060 
100 
120 
130 
140 
150 
160 
170 
180 
190 
200 
210 
220 
230 
240 
250 
260 
270 
280 
290 
300 
310 
320 
230 
340 
350 
360 
370 
380 
400 


388  GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

Record  of  artesian-well  boring  at  Northampton — Continued. 
[Abbreviations:  q,  quartz;  f,  feldspar;  m,  muscovite;  b,  biotite;  g,  garnet.] 


Kind  of  rock. 


Coarse,  brown  sand,  q.  f.  m . 

Same 

Same 


Coarse,  brown  sand,  q.  f.  m.,  1  grain  10™™ ;  second  piece, 

deep-red,  fine,  micaceous  sandstone 

Coarse,  brown  sand,  q.  f.  m 

Medium,  brown  sand,  q.  f.  m 

Same 


Fine,  bufif8and,q.  f.  m 

Medium,  red  sand,  q.  f.  m 

Medium,  reddish  sand,  q.f.  m 

Same 

Same 

Same 

Same 

Same 

Medium,  buff  sand,  q.  f .  m 

Same 

Same 

Medium,  buff  sand,  q.  f.  m. ;  more  rusty 

Medium,  brown  sand,  q.  f.  m. ;  more  rasty. 

Fine,  brown  sand,  q.  f .  m. ;  more  rusty 

Same 

Medium,  buff  sand,  q.  f.  m 

Medium,  buff  sand,  q.  f.  m 

Same 

Same 

Fine,  brown  sand,  q.  f.  m 

Same 

Same 


Same 

Same 

Same 

Medium,  brown  sand,  q.  f.  m. 

Same 

Same 

Same 

Same 

Same 

Same 


Average 

grain,  in 

millimeters 


1  to  2 
1  to3 
1    to3 

1  to3 
1  to3 
1  to2 
1  to2 
itol 
1  to2 
to  2 
to  2 
to  2 
to  2 
to  2 
to  2 
to  2 
to  2 
to  2 


1    to2 
itol 
itol 
1    to2 
1    to2 
1    to2 
1    to2 
itol 
itol 
-..    i 
ito   i 
i-to    i 
ito    i 
ito   4 


to  2^ 
to  2 
to  2 
to  2 
to  2 
4tol 
itol 


Feet. 


2,410 
2,420 
2,430 

2,440 
2,450 
2,460 
2,470 
2,480 
2,490 
2,500 
2,510 
2,520 
2, 530 
2,540 
2,550 
2,560 
2,570 
2,580 


2,754 
2,770 
2,774 
2,826 
2,851 
2,872 
2,901 
2,933 
3,024 
3,100 
3,200 
3,250 
3, 300 
3,350 
3,500 
3,525 
3,536 
3,550 
3,650 
3,675 
3,700 


PSEUDOMORPHS  OF  CALCITE  AND  DOLOMITE.  389 

WELL   ON   WKSTFIELD   LITTLE   RIVER   SOUTH   OF   WESTPIELD. 

Artesian  well  at  Crane  Brothers'  paper  mill,  on  Westfield  Little  River, 
south  of  Westfield;  bored  by  Daniel  Dull,  New  York.  Sunk  1,110  feet  in 
conglomerate;  unsuccessful  and  now  closed  up.  A  soft,  black,  pulverulent 
layer  reported. 

PSEUDOMORPHS   OF   CALCITE   AND   DOLOMITE   AFTER   HOPPER- 
SHAPED   CUBES   OF  SALT. 

It  has  been  reported  for  many  years  that  chiastolites  occurred  in  the 
sandstone  in  West  Springfield,  but  I  can  not  find  that  anything  has  been 
published  upon  the  subject. 

Specimens  containing  small  white  crosses  of  about  the  size  of  ordinary 
chiastolites  and  having  some  resemblance  to  them  were  brought  to  me 
some  years  ago  by  a  student,  who  informed  me  that  they  were  discovered 
by  Mr.  B.  Hosford,  of  Springfield.  These  specimens  were  lost  in  the  fire 
which  destroyed  the  Shepard  collection.  Later,  through  the  kindness  of 
Mr.  J.  S.  Diller,  I  received  another  specimen  with  permission  to  sacrifice  it, 
and  I  had  several  slides  cut  from  it.  It  shows  white  squares  and  triangles 
on  a  black  ground  of  fine-grained,  shaly,  bituminous  sandstone,  but  this 
ground  is  not  marked  off  from  the  rest  of  the  surface  of  the  sandstone  by 
any  square  or  round  boundary  representing  the  cross-section  of  a  prismatic 
crystal  in  which  the  white  lines  should  be  diagonal,  so  that  the  resemblance 
to  chiastolite  is  only  superficial.  These  slides  are  figured  in  the  Miner- 
alogical  Lexicon^  of  the  three  counties. 

On  touching  the  white  areas  with  acid  an  abundant  effervescence 
occurred,  and  under  the  microscope  they  proved  to  be  made  up  of  calcite, 
quite  white  and  coarsely  granular  down  the  central  portion  of  the  bands 
and  very  finely  granular  and  gathered  in  minute  rounded  concretions  just 
visible  with  the  lens  on  either  side  of  these  central  bands,  the  concretions 
grouped  with  more  or  less  of  the  dark  ixiaterial  of  the  sandstone  inter- 
vening, so  as  to  give  the  whole  a  brownish  shade.  The  calcite  was  not 
confined  to  these  bands,  but  impregnated  large  portions  of  the  sandstone, 
so  that,  when  polished,  parts  where  there  was  no  calcite  remained  dull  and 
other  patches  took  a  fine  polish.     It  is  plain  that  cubical  crystals  of  salt 

1  Bull,  U.  S.  Geol  Survey  No.  126,  1895,  under  "Salt." 


390  GEOLOGY  OP  OLD  HAMPSHIEE  COUNTY,  MASS. 

with  excavated  hopper-shaped  faces  had  been  embedded  in  the  mud,  dis- 
solved out,  and  their  j)lace  taken  by  the  calcite,  which  has  largely  impreg- 
nated the  sandstone,  but  which  shows  the  white  color  only  where  it  occupied 
the  cavities  of  the  salt  hoppers. 

The  locality  as  given  me  by  Mr.  Diller  is  along  the  south  bank  of  the 
Westfield  River,  in  West  Springfield,  near  the  water's  edge,  and  just  below 
the  large  dam  some  distance  above  (west  of)  West  Springfield  village. 

Later  a  specimen  was  found  at  Holyoke,  near  the  west  end  of  the  rail- 
road bridge,  and  is  now  in  the  Smith  College  collection.  It  is  larger  and 
much  more  delicate  than  the  Westfield  specimens.  It  is  figured  and  described 
in  detail  in  the  Mineral  Lexicon.^  The  piece  must  have  come  from  a  very 
short  distance  northwest,  and  I  have  observed  single  hopper-shaped  casts  in 
the  shale  at  the  cutting  within  the  city  of  Holyoke,  and  similar  forms  on  the 
shale  at  Ashley's  pond,  farther  west,  and  at  many  other  localities  in  the 
shale.  In  1895  a  large  share  of  the  finest  specimens  collected  by  Mr.  Hos- 
ford  came  into  my  possession — the  best  piece  of  all  through  the  kindness  of 
his  daughter.  This  is  a  finely  ice-polished  slab  of  black  shale,  covered  with 
small  white  figures,  three  or  four  to  the  square  inch,  in  great  variety,  formed 
by  the  various  cross-sections  of  single  and  aggregated  cubes,  whose  faces 
were  excavated  into  hopper  shapes  to  various  depths.  Three-rayed,  four- 
rayed,  and  six-rayed  forms  were  most  common.  The  center  of  each  ray, 
marking  the  trace  of  the  six  planes  which  connect  the  cube  edges,  is  gener- 
ally very  dark,  so  that  it  stands  out  against  the  white  calcite,  and  where  the 
faces  are  only  slightly  excavated,  so  that  the  calcite  is  now  nearly  a  square, 
the  resemblance  to  a  chiastolite  is  striking.  This  darker  band  is  calcite 
colored  by  petroleum  or  coaly  matter,  and  in  some  cases  it  is  a  quite  wide 
band  of  pure  asphaltum. 

It  would  seem  that  the  solution  of  the  salt  and  its  replacement  by  white 
calcite  progressed  slowly  from  the  outside  at  a  low  temperature.  At  the 
last  the  central  band  of  salt  was  removed  and  calcite  took  its  place  when 
somewhat  more  elevated  temperature  prevailed,  so  that  bituminous  matters 
were  distilled  into  the  empty  spaces  along  with  the  last  calcite.  In  other 
specimens  cubes  are  found  with  only  slightly  excavated  faces,  which  are 
made  of  quite  coarsely  crystalline  calcite,  irregularly  colored  by  bitumen. 
Other  pieces  have  slickensided  faces,  with  surfaces  of  fine-fibrous  graphite 

'  Bull.  V.  S.  Geol.  Survey,  No.  126,  1895,  under  "Salt." 


THK  TKIASSIC  SANDSTONE  AS  A  BUILDING  STONE.  391 

(which  is  rcMUiirkable,  as  there  is  here  no  other  trace  of  marked  heat 
action),  together  with  veins  of  coarse-fibrous  calcite,  grains  of  galena,  and 
films  of  gypsum.  Other  cubes  are  flat-faced,  but  a  little  elongate,  and  made 
of  fine-grained  calcite.  At  times  the  rays  are  broadly  bordered  by  delicate 
feathery  growths  of  white  limestone,  which  shows  a  fine,  concretionary, 
almost  oolitic  structure  imder  the  microscope. 

The  thin-bedded  rusty  sandstone  from  the  island  at  Turners  Falls,  which 
contains  the  ferruginous  concretions,  contains  also  remarkable  salt  pseudo- 
morphs — skeleton  cubes  with  each  bar  nearly  an  inch  long.  The  interspaces 
are  now  filled  with  limonite,  which  was  doubtless  at  first  an  iron  carbonate. 

THE   USE   OF  THE  TRIASSIC   SANDSTONE  AS   A  BUILDING   STONE. 

The  Sugar  Loaf  arkose  is  somewhat  used  for  rude  masonry,  such  as 
embankments,  walls,  bridge  piers,  etc.  The  large  qxiarry  on  the  northwest 
shoulder  of  Mount  Tom  furnished  the  stone  for  the  piers  of  the  railroad 
bridge  over  the  Connecticut  River  at  Northampton,  and  had  been  long 
worked  for  similar  purposes.  The  rock  is  too  coarse  for  architectural  use; 
if  it  were  not  its  light  color  would  make  it  very  valuable. 

The  Longmeadow  sandstone,  under  the  name  "  brownstone,"  has  been 
for  a  long  time  in  high  repute  as  a  building  stone  of  the  greatest  value,  and 
it  has  been  exported  to  great  distances  and  employed  upon  the  most  expen- 
sive buildings.  The  report  Mineral  Resources  of  the  United  States  for 
1890^  states  that  the  sandstone  produced  in  Massachusetts  during  that  year 
was  valued  at  S649,097,  and  of  this  amount  $563,179  was  furnished  by 
Hampden  County,  and  came  from  the  quarries  extending  south  from  Six- 
teen Acres,  in  Springfield,  to  East  Longmeadow. 

The  following,  copied  from  an  article  in  the  Springfield  Republican 
of  May  9,  1884,  and  verified  by  me  in  all  important  particulars,  gives  a 
good  account  of  the  industry  at  that  date : 

The  Norcross  Brothers  are  the  largest  shippers  of  stone  from  East  Long- 
meadow, having  last  year  loaded  115,000  cubic  feet  of  brownstone  for  building 
purposes  on  about  900  freight  cars.  In  addition  to  this  amount,  35,000  cubic  feet 
■was  quarried  during  the  year,  but  kept  in  the  yard  to  furnish  winter  work  for  the 
stonecutters.  Two  quarries,  located  within  a  mile  of  the  East  Longmeadow  depot, 
the  Saulsbury  and  Kibbe,  furnish  all  but  a  small  part  of  tlie  product  and  give 


'Issued  by  the  United  States  Geological  Survey,  p.  402. 


392       GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

employment  to  about  200  men  for  a  greater  portion  of  the  year.  There  is  also  a 
third,  yielding  a  finer-grained,  harder  stone,  which  occurs,  however,  in  a  thinner 
stratum  and  at  greater  depths  below  the  soil,  so  that  it  is  now  used  only  on  special 
orders.  All  the  stone  is  brownish-red  iu  color,  does  not  flake  on  exposure  to  the 
weather,  is  free  from  stratification,  and  evenly  hard  throughout— that  from  the 
Kibbe  having  a  somewhat  richer  red  hue  than  the  others.  Tbe  quarries  are  located 
on  nearly  flat  ground,  and  the  sandstone  croppings  are  over  10  feet  thick,  with  a 
dip  toward  the  southeast  of  about  10  degrees.  As  the  line  of  the  dip  is  followed 
the  stone  becomes  finer  in  texture  and  harder,  and  the  stratum  also  thickens,  until, 
when  covered  by  20  feet  of  soil,  it  forms  a  layer  from  20  to  30  feet  through  Above 
the  stone  is  found  a  mass  of  slaty  brownstone,  and  below  it  is  the  same  material, 
although  explorations  indicate  the  existence  of  another  stratum  of  good  rock  at  a 
small  distance  below  the  first.  But  little  powder  is  used  in  quarrying,  most  of  the 
work  being  done  with  picks  and  wedges.  Blocks  weighing  in  the  rough  from  5  to 
6  tons  are  frequently  taken  out  and  sometimes  shipped  uncut,  and  one  block  of  12 
tons  weight  has  been  successfully  quarried  and  raised.  Water  causes  much  trouble 
and  expense,  and  in  the  Saulsbury  workings  a  steam  pump,  throwing  60  gallons  a 
minute,  is  employed  for  an  average  of  twelve  hours  a  day  to  keep  down  the  flow 
from  springs  and  surface  drainage.  The  quarry  work  lasts  from  April  to  Decem- 
ber, and  during  the  winter  months  a  force  of  laborers  is  employed  in  stripping  the 
rock  and  removing  the  soil  and  waste  to  old  workings.  About  half  of  the  stone 
quarried  is  dressed  before  shipment. 

The  firm  is  now  using  Longmeadow  stone  either  iu  solid  walls  or  as  trimmings 
on  the  following  contracts :  The  Union  Theological  Seminary,  a  four-story  200  by  125 
foot  building,  on  Park  avenue,  ISTew  York,  which  will  cost  $300,000  when  finished 
in  May:  the  St.  James  Episcopal  Church,  to  cost  $125,000,  and  cover  a  space  of 
120  by  72  feet  on  Madison  avenue,  New  York;  the  Jefferson  Physical  Laboratory 
for  Harvard  College,  a  four-story  building,  70  by  212  feet,  with  the  peculiarity  that 
in  portions  of  it  no  iron,  even  in  the  form  of  nails,  will  be  used  on  account  of  pos 
sible  magnetic  action;  for  the  University  of  \^ermont,  at  Burlington,  a  library 
building  of  Kibbe  sandstone,  to  cost  $100,000;  on  Eighth  street,  St.  Louis,  Missouri, 
an  eight-story  64  by  130  foot  building,  to  cost  $225,000,  for  the  use  of  the  Turner 
Eeal  Estate  and  Building  Association ;  at  Lawrenceville,  New  Jersey,  eight  buildings, 
to  cost  $325,000,  for  the  Lawrenceville  Academy.  The  Norcross  Brothers  quarry 
three  shades  of  stone,  the  trade  names  by  which  they  are  known  being  "  Maynard,"  a 
bright-red  stone;  "  Kibbe,"  a  dark-red;  and  "  Worcester,"  a  brown. 

There  are  a  number  of  Springfield  men  interested  m  getting  out  stone  for 
buildings,  and  the  East  Longmeadow  quarry  of  James  &  Marra,  of  this  city,  lies 
near  the  Norcross  Brotliers  works,  and  the  stone  obtained  from  it  much  resembles 
the  Kibbe  rock  in  quality,  although  of  a  slightly  lighter  color.  The  quarry  was 
first  worked  about  sixty  years  ago  by  a  man  named  Saulsbury,  but  only  small 
amounts  of  stone  were  taken  out  until  it  passed  into  the  hands  of  Nathaniel  Billings 
la  1882  the  present  owners  bought  the  property  of  him,  and  have  since  added  to 


THE  TRIASSIO  SANDSTONE  AS  A  BUILDING  STONE.  393 

it,  iiutil  tliey  now  own  174  acres  of  good  stone  laud  and  two  more  (luanies,  both 
of  which  have  been  opened,  but  are  now  unworked.  In  the  Billings  workings  the 
rock  was  L'O  feet  thick  where  first  qnarried,  but  by  following  its  dip  of  about  10 
degrees  to  the  southeast  the  owners  tind  it  increased  to  40  feet  of  unstratitied  and 
little  seamed  stone.  About  20  feet  of  earth  cover  the  layer  of  stone  at  present 
worked,  and  below  it  is  found  a  deposit  of  soft,  shaly  rock.  Water  is  a  trouble- 
some feature  of  this  quarry,  and  a  steam  pump  is  kept  at  work  much  of  the  time. 
During  nine  mouths  85  men  are  employed  around  the  works,  10  of  whom  are 
stonecutters;  the  same  firm  keeps  25  cutters  at  work  in  the  Franklin  street  yard 
in  Springfield.  About  100,000  cubic  feet  of  rock  was  shipped  from  the  quarry  last 
year,  and  nearly  half  of  this  amount  was  dressed  before  it  was  sent  away.  The 
largest  contracts  for  stone  either  completed  within  a  year  or  now  being  finished 
are:  An  order  for  20,000  feet  for  Judge  Tree's  house  in  Chicago,  Illinois;  for  the 
Union  League  Clubhouse,  Chicago,  35,000  feet,  and  for  the  Second  Congregational 
Church,  Holyoke,  35,000  feet. 

The  Springfield  quarry,  located  within  the  city  limits,  4  miles  out  on  the 
Hampden  road,  owned  by  W.  &  E.  W.  Pease,  was  first  worked  in  1882,  and  lies 
on  a  tract  of  30  acres,  bought  from  John  Eockford.  The  ledge  first  quarried  was 
20  feet  thick  at  the  croppings  and  of  fine  quality  browustone,  but  at  a  few  feet 
below  the  surface  a  large  spring  was  struck,  which  made  operations  too  expensive. 
In  the  second  opening  two  ledges,  each  12  and  14  feet  thick  and  separated  by  a 
layer  of  shaly  stone,  are  worked,  and  20  feet  of  sand  is  at  present  removed  to  get 
at  the  deposit,  which  dips  toward  the  southeast  at  an  angle  of  about  30  degrees. 
Water  has  not  yet  proved  troublesome.  About  50  men  are  employed,  and  last 
year  nearly  100,000  feet  of  stone  was  shipped  over  the  New  England  Eoad,  mainly 
to  the  eastern  part  of  this  State.  The  Palmer  depot  and  the  new  Taftsville  mill 
are  conspicuous  examples  of  buildings  trimined  with  stone  from  this  quarry. 

The  Carlisle  Stone  Company  owns  a  browustone  quarry  not  far  from  Sixteen 
Acres,  and  last  year  employed  26  men  and  shipped  to  Boston  by  way  of  the  Indian 
Orchard  depot  25,000  cubic  feet  of  rock,  of  which  only  a  small  proportion  was 
dressed.  A  tract  of  60  acres,  including  the  present  quarry,  which  was  first  worked 
four  years  ago,  was  bought  by  the  company  in  1881,  and  the  stone  obtained  since 
that  time  bas  been  of  fine  quality,  although  of  a  lighter  red  color  than  Longmeadow 
stone.  The  stratum  is  18  feet  thick,  dips  about  15  degees  to  the  east,  and  is  cov- 
ered by  12  feet  of  sand  and  2  feet  of  hardpan.  No  shaly  rock  is  found,  but  flinty 
bowlders  occur,  and  water  causes  considerable  trouble  in  the  spring  months. 

M.  A.  Glynn  works  a  quarry  at  East  Longmeadow,  about  a  mile  north  of  the 
depot,  and  obtains  a  fine  quality  of  browustone,  which  he  sells  undressed  to  several 
New  England  dealers.  The  Glynn  quarry  was  opened  ten  or  twelve  years  ago, 
but  was  worked  only  a  little.  It  was  bought,  with  7  acres  of  land,  by  the  present 
owner  a  year  ago  from  the  Enfield  Shakers.  The  rock  is  covered  by  5  feet  of 
earth,  without  hardpan  or  shaly  material,  and  is  of  uncertain  thickness,  having 
been  worked  only  to  a  depth  of  16  feet  as  yet.  Water  is  not  troublesome.  Last 
year  8  quarrymen  were  employed  and  12,000  cubic  feet  of  stone  were  sold. 


394  GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

Mr.  Greorge  P.  Merrill^  gives  the  following  data:  Price  per  cubic  foot, 
$1  to  S2;  cost  of  pointing,  10  to  15  cents;  ax-hammering,  30  cents.  An 
extra  price  is  charged  for  blocks  of  more  than  25  cubic  feet.  Strength  of 
the  sandstone  per  square  inch,  8,945,  8,812. 

The  stone  sells  now  (1893)  for  60  to  70  cents  per  cubic  foot  deliv- 
ered at  the  station,  while  the  Berea  stone  sells  for  $1  per  foot  delivered  in 
Springfield. 

PAIiEONTOLOGY. 

In  the  following  section  I  have  given,  by  means  of  the  synonymy,  the 
history  of  opinion  concerning  each  species  known  to  me,  and  each  locality 
where  the  species  has  been  found. 

I  have  not,  however,  given  special  attention  to  the  foot-tracks,  and 
present  only  the  latest  list  of  species  prepared  by  Professor  Hitchcock. 

PLANTS. 

Halymenites  shepardi  E.  Hitchcock. 

1833.  Fueoides  sp.     E.  Hitchcock.     Geol.  Mass.,  p.  233,  pL  13,  flgs.  38, 39. 

1835.  Same. 

1811.  Fueoides  shepardi  E.  Hitchcock.     Geol.  Mass.,  Pinal  Eept.,p.  455,  flg.  95. 

These  forms  occur  so  abundantly  throughout  the  central  areas  of 
fine-grained  sandstones  and  shales  that  I  have  often  called  these  the  fucoidal 
sandstones.  The  best  locality,  in  addition  to  those  mentioned  below,  is  at 
the  water  shops  in  Springfield.  I  append  Hitchcock's  description,  premising 
that  branching  is  not  so  rare  as  it  would  indicate.  Bauds  of  the  sandstone 
several  feet  thick  are  at  times  filled  evenly  full  of  these  rods,  and  inter- 
vening bauds  are  empty,  as  at  the  mouth  of  Fall  River: 

This  relic  varies  in  size  from  one-tenth  of  an  inch  to  an  inch  in  diameter.  More 
commonly  it  runs  through  the  rock  in  a  direction  corresponding  to  that  of  the  laminae, 
in  which  case  it  is  considerably  flattened.  Sometimes  it  passes  obliquely  through 
the  layers,  and  very  commonly  crosses  them  at  right  angles,  in  which  last  case  it 
has  a  cylindrical  form.  It  is  rare  to  see  a  specimen  of  any  considerable  length  that 
is  not  more  or  less  curved,  and  I  have  never  met  with  one  that  was  branched 
at  all.  I  have  noticed  specimens  a  foot  or  more  in  length,  and  they  may  be  much 
longer  than  this,  since  I  have  not  met  with  any  large  mass  of  rock  containing  them. 
The  sandstone  in  which  they  are  found  is  rather  fine  and  quite  soft  and  easily 
disintegrates.    They  occur  near  Hoyt's  quarries,  1  mile  west  of  the  village  of  Deer- 


'Cat.  Nat.  Mus.,  Washington,  pp.  54,  499. 


PALEONTOLOGY.  395 

(iekl,  and  also  a  few  rods  south  of  the  county  jail  in  Greenfiejd,  close  by  the  stage 
road,  and  on  the  road  to  TJernardstou,  a  mile  north  of  the  village  of  Greenfield. 

The  vegetable  matter  in  these  remains  is  wholly  replaced  by  sandstone.  By 
breaking  the  specimens  transversely  a  curious  structure  is  revealed.  It  may  be 
described  by  saying  that  the  cylinder  is  made  up  of  convex  layers  of  sandstone  piled 
upon  one  another;  and  I  observe  that  la  the  same  rock  all  the  specimens  have  the 
convex  sides  of  these  layers  in  the  same  direction,  so  that  on  one  side  of  the  rock 
you  will  see  numerous  button-like  protuberances  and  on  the  other  side  correspond- 
ing concavities.  (No.  258.)  Bat  I  do  not  know  which  side  is  uppermost  in  the  rock, 
iu  situ.' 

I  allow  the  above  to  stand,  altliotigli  the  forms  now  seem  to  me  to  be 
tiibulai-  ferruginous  concretions,  the  result  of  the  circulation  of  iron-bearing 
solutions  in  the  sands.  After  forming  the  concretions  the  solutions  have 
gone  on  to  cement  the  intervening  sand  into  a  red  sandstone. 

Of  the  other  figures  presented  in  the  Geology  of  Massachusetts  in  1841 
as  plants,  fig.  89,  p.  451;  fig.  91,  p.  453;  figs.  92  and  93,  p.  454;  and  figs. 
3  and  5  on  pi.  28  (cited  as  29  in  the  text)  are  dubious  impressions,  which 
are  very  common  in  the  sandstones.  Some  may  have  been  caused  by 
fucoids ;  others,  as  fig.  3,  by  the  dragging  of  the  roots  or  branches  of  float- 
ing trees  rising  and  sinking  with  the  waves.  Fig.  94,  p.  454,  represents 
ferruginous  concretions ;  fig.  1,  pi.  28,  is  a  track.  For  fig.  92,  the  name 
Fucoides  connecticutensis  is  suggested  on  p.  453. 

Clathropteris  platyphylla  Bronsfn. 

1841.  "  Peculiar  vegetable  relic,"  like  a  fern.  E.  Hitchcock,  Geol.  Mass.,  p.  452, 
fig.  90.    Teste,  E.  Hitchcock,  jr. 

1854.  C.  rectiusctdus.  E.  Hitchcock,  jr.  Description  of  a  new  species  of  Clathrop- 
teris, discovered  in  the  Connecticut  Valley  sandstone.  Am.  Jour.  Sci.,  2d 
series,  XX,  p.  22 ;  figured  in  the  text. 

1858.  G.  rectiusculus.  E.  Hitchcock.  Ichnology  of  Massachusetts.  PI.  V,  fig.  1; 
PI.  VII,  fig.  1. 

1890.  G.  lylatyphylla  Brongn.  J.  C.  Newberry,  Fossil  Fishes  and  Fossil  Plants  of 
the  Triassic  Eocks  of  New  Jersey  and  the  Connecticut  Valley:  Mon. 
U.  S.  Geol.  Survey,  Vol.  XIV,  p.  94,  PI.  XXII. 

Locality:  Bassett's  quarry,  on  the  west  face  of  Mount  Tom,  in  East- 
hampton,  just  below  the  Holyoke  trap  sheet,  iu  coarse,  buff  arkose.  The 
type  specimen  is  in  the  museum  of  Williston  Seminary,  at  Easthampton. 
A  large  series  in  the  Amherst  College  cabinet,  where  are  also  specimens 
from  the  quarry  of  Roswell  Field,  in  Gill;   also  from  the  banks  of  the 

'  E.  Hitchcock,  Geol.  Mass.,  1841,  p.  456. 


396  GEOLOGY  OF  OJjD  HAMPSHIRE  COUNTY,  MASS. 

Connecticut  in  Moptague,  2  miles  southwest  of  the  latter  place,  as  noticed 
by  E.  Hitchcock  in  1841.  The  latter  localities  are  a  coarse,  gray  arkose. 
I  am  convinced,  from  an  inspection  of  European  specimens  in  the  museum 
at  Munich,  of  the  identity  of  this  species  with  C.  platyphylla. 

Dr.  Newberry  cites,  also,  Westfield,  Massachusetts,  Durham,  Comaecti- 
cut,  and  Newark  and  Milford,  in  New  Jersey. 

Maceot^niopteris  magnifolia  Schimper. 

Small  leaves  for  this  species,  about  3  inches  long,  and  a  little  more 
cordate  than  the  figures.     In  black  shale;   Turners  Falls. 

Maceot^niopteris  sp. 

1843.  Tceniopteris  vitata.    E.  Hitchcock.     Trans.  Assn.  Am.  Geol..  Vol.  I,  p.  294. 

From  a  bowlder  of  dark-gray  sandstone  on  Mount  Holyoke.     The 

impression  is  nearly  2  feet  long.^     I   can  not  find  the  specimen  in  the 

Amherst    collection.      Similar    large    leaves    occur   in   the   north    part   of 

Montague,  on  the  road  going  down  to  the  bridge  to  Grreenfield. 

AsTROCAEPUs  viEGiNiENSis  Fontaine. 

A  very  poorly  ^^reserved  specimen  of  a  large  frond  with  strong  rachis 
and  long,  straight  piimse.  On  buff  arkose,  like  that  under  Mount  Tom, 
containing  Clathropteris.  From  the  collection  of  President  Hitchcock,  who 
said  it  came  from  the  valley,  but  could  not  give  the  exact  locality. 

Pachyphyllum  simile  NewbeiTy. 

1857.   Walehia  variabilis  E.  Emmons.    American  Geology,  p.  108,  fig.  76. 
1890.  Pachyphyllum  simile  Newberry.    Fossil  Fishes  and  Fossil  Plants  of  the, 
Triassic,  p.  88,  PI.  XXII,  fig.  2. 

Includes  the  larger  and  longer  and  sharper-leaved  twigs  of  coniferous 
plants. 

Locality:  Turners  Falls,  in  black  shale. 

Pachyphyllum  brevipolium  Emmons  sp. 

1823.  Unknown  relic.     E.  Hitchcock.    Geology  of  Connecticut  Elver.    Am.  Jour. 

Sci.,  1st  series,  Vol.  VI,  p.  80,  pi.  9,  fig.  5. 
1832.  Lycopodites  sUHmanni  De  la  Beche.    Manual  of  Geology,  2d  ed.,  p.  419. 
1841.  Possibly  a  Voltzia.     E.  Hitchcock.    PI.  28  (cited  29),  fig.  2. 
1843.  Possibly  a  voltzia.    E.  Hitchcock.    Trans.  Ass.  Am.  Geol.,  Vol.  I,  p.  294. 
1857.  Walehia  brevifoUa  E.  Emmons.    American  Geology,  p.  108,  figs.  74,  75. 

1  E.  Hitchcock,  Trans.  Assn.  Am.  Geol.,  Vol.  I,  1843,  p.  294. 


PALEONTOLOGY.  397 

1858.  Cone  and  twig.     E.  Hitchcock.     Ichuology  of  Massachusetts,  IM.  VII,  fig.  2. 
1890.  racliypliijllitm  hrevifolinm  Newberry.     Fossil  Fishes  and  Fossil  Plants  of 
the  Triassic,  PI.  XXII,  figs.  3-3c. 

The  L.  silUmantii  is  quoted  above,  from  Hadley,  Connnecticut,  doubt- 
less a  mistake  lor  Massachusetts,  and  the  phxut  was  carried  from  here  to 
Europe.'  It  Avas  described  (1823)  from  the  fish  locaHty  at  Sunderlaud. 
It  occurs  at  Turners  Falls;  and  I  have  found  it  quite  abundantly  at  the  cut 
just  south  of  the  south  line  of  Holyoke,  below  Holyoke  dam,  and  at  the 
adjacent  cut  on  the  raih-oad  to  Westfield;  also  in  the  northwest  of  Mon- 
tague, where  the  road  goes  down  the  hill  to  Greenfield.  Its  small  cypress- 
like twigs  often  spread  over  slabs  2  or  3  feet  square.  Its  small  cones, 
about  an  inch  long,  are  figured  in  the  last  two  works  cited  above. 

ScHizoNEURA  PLANicosTATA  Rogers  sp. 

1883.  8.  planicostata  Fontaine.     Older  Mesozoic  Flora  of  Virginia:  Mon.  U.  S. 

GeoL  Survey,  Vol.  VI,  p.  14,  PI.  I,  fig.  1. 
1890.  S.  planicostata,  J.  S.  Newberry.    Fossil  Fishes  and  Fossil  Plants  of  the 

Triassic,  p.  87. 

Palissya?  sp. 

Many  flattened  fragments  of  branches  or  stalks  of  plants  occur, 
especially  in  the  arkose.  These  are  transversely  jointed,  from  shrinkage 
in  the  process  of  change  to  bituminous  coal,  and  are  faintly  striated  longi- 
tudinally. Larger  trunks  occur  at  times  as  cylinders  of  sandstone  crossing 
the  laminations  of  the  sandstone,  12  to  20  inches  in  diameter. 

President  Hitchcock  mentions  stems  of  plants  "converted  into  vesic- 
ular amygdaloid,"  and  he  figures  a  specimen  from  a  bowlder  in  Amherst, 
which  he  evidently  supposes  came  from  the  upper  portion  of  the  Greenfield 
trap  sheet.^  Trunks  of  this  kind  are  doubtfully  referred  to  the  above 
coniferous  genus  by  Dr.  Newberry.  The  specimen  is  a  tapering,  rough- 
surfaced  rod,  of  rounded,  cordate  cross-section,  2  feet  long,  2^  by  IJ  inches 
at  one  end,  and  1|  by  1  inch  at  the  other. 

The  inclosing  rock  is  a  dark  greenish-gray  diabase,  of  the  type  of 
the  freshest,  medium-grained  rock  of  the  Deerfield  bed. 

The  tube  is  made  up  of  a  slightly  finer  diabase,  with  steam  cavities 
filled  with  delessite.  There  is  no  trace  of  tuff  sti-ucture  in  the  rock  or  in 
the  slides  of  either  portion.     It  is  a  case  where  a  branch  was  enclosed  in 

'E.  H.  Lee,  Geol.  Eept.  1833,  p.  233. 

2  6eol.  Mass.,  Final  Kept.,  1841,  p.  457,  fig.  96. 


398  GEOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 

the  liquid  lava,  burned,  and  the  cavity  immediately  after  filled  with  lava 

from  above.     I   have  collected   such   specimens   at   Kilauea.     This  rock 

came  probably  from  near  the  south  end  of  the  Deerfield  sheet,  where  the 

river   crosses  it,  and   where   several   amygdaloidal   beds   show  that   the 

sheet  is  made  up  of  a  number  of  successive  flows,  one  quickly  following 

another. 

LopEEiA  SIMPLEX  Nowberry.-^ 

Professor  Newberry  has  given  this  name  to  the  plants  whose  stems 
appear  commonly  as  simple  cylinders  about  an  inch  across.  They  occur 
abundantly  in  Springfield,  and  were  filled  at  one  locality  by  a  sand  that 
differs  from  that  which  inclosed  them  by  its  freedom  from  mica  scales  and 
its  pale-green  color. 

INSECTS. 

MORMOLUCOIDES    ARTICULATUS    E.  HitchcOck. 

1858.  M.  articulatus  E.  Hitchcock.    Ichnology  of  New  England,  pp.  7,  8,  pi.  7, 

figs.  3,  4,  with  letter  of  Professor  Dana. 
1862.  Palephemera  medieva  E.  Hitchcock.    Am.  Jour.  Sci.,  2d  series,  Vol.  XXXIII, 

p.  452. 
1867.  M.  articulatus  S.  H.  Scudder.    Proc.  Boston  Soc.  Nat.  Hist.,  Vol.  XI,  p.  140; 

Geol.  Mag.,  Vol.  V,  p.  218. 
1871.  M.  articulatus  A.  Packard.    Bull.  Essex  Inst.,  Vol.  Ill,  p.  1. 
1886.  M.  articulatus  S.  H.  Scudder.    The  Oldest  Known  Insect-Larva,  from  the 

Connecticut  Eiver  Eocks.    Mem.  Bost.  Soc.  Nat.  Hist.,  Vol.  Ill,  p.  431. 

These  remarkable  forms  were  found  in  considerable  numbers  in  the 
fine  black  shale  at  Turners  Falls.  A  series  of  slabs  containing  each  a  great 
number  of  indviduals  is  preserved  in  the  museum  of  Amherst  College.  A 
full  history  and  description  of  the  species  and  abundant  illustrations  are 
given  in  the  last  article  cited  above. 

Professor  Dana  first  decided  that  the  form  was  a  neuropterous  larva. 
Mr.  Scudder  and  Professor  Packard  concluded  that  it  was  a  coleopterous 
larva.  In  the  last  work  Mr.  Scudder  returns  to  the  first  conclusion,  that  it 
is  probably  the  larva  of  a  sialidan  neuropteron. 

FISHES. 

The  monograph  upon  the  fossil  fishes  of  the  Trias,^  by  Dr.  Newberry, 
should  be  consulted  by  anyone  wishing  to  become  acquainted  with  what 

'Fossil  Fishes  and  Fossil  Plants  of  the  Triassic:  Men.  U.  S,  Geol.  Survey,  Vol.  XIV,  1888,  p.  93, 
PI.  XXV,  figs.  1-3. 
'^  Idem. 


PALEONTOLOGY.  399 

is  known  conceruiu'''  tlie  fossil  Hshes  of  this  region,  and  the  numerous 
and  accurate  phites  will  enable  him  to  determine  the  name  and  character 
of  an\-  specimen  found.     Dr.  Newberry  says : 

Fishes  seem  to  be  equally  abundant  in  the  Connecticut  lliver  basin.  At  Dur- 
ham, Couuecticut,  and  Turners  Falls,  Massachusetts,  they  are  particularly  numerous 
and  well  preserved,  while  they  have  also  been  obtained  at  Middletown,  Sudbury, 
Chicopee,  Amherst,  and  Hadleys  Falls.' 

In  this  list  Sudbury  must  be  changed  to  Sunderland,  and  Hadleys 
Falls  to  South  Hadley  Falls ;  and  Amherst  must  be  canceled,  as  only 
coarse  arkose  occm-s  in  Amherst,  and  no  fishes  have  been  found  there. 

At  Turners  Falls,  on  the  east  bank  of  Fall  River,  a  few  rods  above  the 
bridge,  at  the  southeast  corner  of  the  island,  a  few  feet  above  the  point 
where  the  dam  abuts,  and  on  the  mainland  directly  north  of  this  spot,  in  the 
line  of  strike  at  the  foot  of  the  bluffs  and  near  the  water's  edge,  many 
specimens  can  be  obtained  by  digging  in  the  black  shales. 

At  Whitmores  Ferry,  Sunderland,  in  the  north  part  of  the  town,  in 
rocks  exposed  only  at  low  water,  numerous  impressions  may  be  found. 
Good  specimens,  carefully  and  skillfully  developed,  can  be  purchased 
of  the  owners  of  the  mill  adjacent.  The  slabs  are  left  out  during  the 
winter  and  split  by  the  frost,  so  as  to  expose  the  impressions  of  fishes  to 
the  best  advantage. 

Hadleys  Falls,  mentioned  by  Newberry,  must,  I  think,  be  South 
Hadley  Falls  Canal,  as  fishes  were  found  during  the  digging  of  this  canal, 
and  are  now  deposited  in  the  museum  of  Amherst  College.  The  specimens 
from  this  locality  do  not  seem  to  have  been  examined  by  Professor  New- 
berry, as  he  does  not  cite  any  species  from  there.  Those  in  the  Amherst 
Musuem  were  by  oversight  not  submitted  to  him. 

Chicopee  Falls  has  not  afforded  anything,  so  far  as  I  know,  for  many 
years.  The  excavations  made  during  the  building  of  the  dam  and  mills 
may  have  supplied  the  specimens  which  fell  into  the  hands  of  Mr.  Red- 
field,  and  furnished  the  material  for  the  new  species  which  Dr.  Newberry 
has  named  for  this  town.  There  are  no  specimens  from  this  place  in  the 
Amherst  collection. 

I  have  given  below  a  list  of  the  forms  which  have  been  identified  in 
Massachusetts,  and  a  word  concerning  the  history  of  the  more  interesting 

'  Loo.  cit.,  p.  21. 


400       GEOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 

species.  Excepting  the  rare  form  found  at  Chicopee,  it  will  be  seen  that 
they  are  all  referred  to  two  ganoid  genera,  Ischypteras  of  Sir  Phillip 
Egerton,  which  is  characterized  by  the  great  strength  of  the  fin  rays,  and 
Catopterus,  distinguished  by  the  posterior  position  of  the  dorsal  fin. 

Most  of  the  specimens  found  belong  to  the  two  species  Iscliyptems 
tenuiceps  and  Catopterus  gracilis. 

Ischypterus  ovatus.  W.  C.  Eedfield.  Sunderland  (Eedfield),  Turners  Falls  (New- 
berry). 

Ischypterus  marshii  W.  0.  R.    Sunderland  (Eedfield). 

Ischypterus  micropterus  N.     Sunderland. 

Ischypterus  tenuiceps  Ag.,  sp.  Turners  Falls.  Sunderland.  Figured  by  E.  Hitch- 
cock.   Geol.  Mass.,  1841,  Vol.  II,  p.  459,  PI.  XXIX,  figs.  1,  2. 

Ischypterus  macropterus  W.  0.  E.    Sunderland. 

Ischypterus  parvus  W.  0.  R.  Sunderland.  Figured  by  Hitchcock,  Geol.  Mass., 
1835,  Atlas  XIV,  fig.  44,  and  1841,  PI.  XXIX,  fig.  3. 

Ischypterus  latus  J.  H.  E.    Sunderland, 

Ischypterus  elegans.    Sunderland. 

Catopterus  gracilis  J,  H.  E.     Sunderland, 

Catopterus  parvulus  W,  C,  E.     Sunderland, 

Acentrophorus  chieopensis  N,    Chicopee  Falls, 

ICHNOLOGY. 

Since  the  publication  of  the  Ichnology  of  Massachusetts  and  its  Sup- 
plement, which  President  Hitchcock  looked  upon  as  closing  the  most 
original  scientific  investigation  of  his  life,  but  little  has  been  done  to 
advance  the  knowledge  of  this  the  most  peculiar  contribution  of  the  Con- 
necticut Valley  to  geology,  except  what  has  been  published  by  Prof 
C.  H.  Hitchcock,  who  has  kindly  permitted  me  to  print  in  this  place  a 
portion  of  an  article  upon  the  subject,  containing  his  latest  views  upon  the 
classification  of  these  foi'ms,  from  the  proceedings  of  the  Boston  Society 
of  Natural  History,  Vol.  XXIV,  1889,  p.  117.  The  article  has  been  cor- 
rected by  Professor  Hitchcock  (1892). 

Ebcent  Pbogkess  in  Ichnology. 

By  C.  H.  Hitchcock. 

The  study  of  the  Ichnozoa,  or  the  animals  that  made  the  tracks,  naturally, 
divides  itself  into  three  parts:  First,  an  examination  of  the  ichnites  themselves;  sec- 
ond, the  restorations  of  the  animals  from  their  bones,  and  third,  comparisons  of  the 


PALEONTOLOGY. 


401 


impressions  made  by  livinj;  animals  with  the  Triassic  imprints.    I  will  at  present 

speak  only  of  the  first. 

Allow  me  to  present,  at  the  outset,  a  complete  list  of  the  Triassic  Ichnozoa, 
arranged  in  convenient  classes.  It  will  not  be  needful  to  state  the  reasons  why  cer- 
tain species  of  the  Ichnology  are  dropped.  The  number,  after  several  erasures,  haa 
increased  from  150  of  the  Ichnology  to  170.> 

ICHNOZOA   or   THK   TRIAS. 

Marsripial. 

Cunichnoides  marsupialoideus  E.  H. 

Birds,  Pachydaotylous. 


Brontozoum  glganteum  C.  H.  H. 

approximatum  C.  H.  H. 

minusculum  E.  H. 

divaricatum  E.  H. 

tuberatum  E.  H. 

exsertum  E.  H. 

validum  E.  H. 

sillimanium  E.  H. 
Amblonyx  giganteus  (?)  E.  H. 

(?)  Birds,  Lepiodaciylous 

Argozoum  redfieldianum  (?)  E.  H. 
dispari-digitatum  E.  H. 


Amblonyx  lyellianus  ( ?)  E.  H. 
Grallator  cursorius  E.  H. 

parallelus  E.  H. 

tenuis  E.  H. 

gracilis  C.  H.  H. 

cuneatus  Barratt. 

formosus  E.  H. 
Leptonyx  lateralis  E.  H. 


Argozoum  pari-digitatum  E.  H. 


Dinosaurs. 


Anomoepus  major  E.  H. 

isodactylus  C.  H.  H. 
intermedins  E.  H. 
curvatus  E.  H. 
minor  E.  H. 
cuneatus  C.  H.  H. 
minimus  E.  H. 
gracillimus  C.  H.  H. 
Gigantitherium  caudatum  E.  H. 

minus  E.  H. 
Hyphepus  iieldi  E.  H. 
Corvipes  lacertoideus  E.  H. 
Tarsodactylus  expansus  C.  H.  H. 

caudatus  E.  H. 
Apatichnus  crassus  C.  H.  H. 

holyokensis  C.  H.  H. 
circumagens  E.  H. 
bellus  E.  H. 
Plesiornis  quadrupes  E.  H. 
pilulatus  E.  H. 
sequalipes  E.  H. 
mirabilis  E.  H. 


Plesiornis  giganteus  C.  H.  H. 

n.  sp.  C.  H.  H. 
CliimsBriclinus  ingens  C.  H.  H. 

barrattii  E.  H. 
Anticheiropus  hamatus  E.  H. 
pilulatus  E.  H. 
Platypterna  deaniana  E.  H. 

tenuis  E.  H. 

delioatula  E.  H. 

recta  E.  H. 

varica  E.  H. 

digitigrada  E.  H. 
Ornithopus  gallinaceus  E.  H. 

gracilior  E.  H. 
Tridentipes  ingens  E.  H. 

elegans  E.  H. 

elegantior  E.  H. 

insignis  E.  H. 

uncus  (?)  E.  H. 
Trihamus  elegans  E.  H. 

magnus  C.  H.  H. 


>A  catalogue  of  the  Ichnozoa,  as  they  were  known  in  1871,  was  prepared  by  me  for  Walling  and 
Gray's  Official  Atlas  of  Massachusetts. 
MON  XXIX 26 


402 


GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 


Polemarchus  gigas  E.  H. 
Plectropterna  minitans  E.  H. 
gracilis  E.  H. 
angusta  E.  H. 
lineans  E.  H. 
Triaenopus  leptodactylus  E.  H. 
Harpedactylus  gracilis  E .  H. 
gracilior  E.  H. 
crasBus  E.  H. 
n.  sp.  C.  H.  H. 
Xiphopeza  triples  E.  H. 
Toxiclinus  insequalis  E.  H. 
Orthodaotylua  floriferus  E.  H. 

iutrorergens  E.  H, 

Otozoum  moodii  E.  H. 

caudatum  C.  H.  H. 
parvum  C.  H.  H. 
Batrachoides  nidificans  E.  H. 
Palamopus  clarki  E.  H. 
Macropterna  vulgaris  E.  H. 

divaricans  E.  H. 
gracilipes  E.  H. 

Ancyropus  teteroclitus  E.  H. 
Chelonoides  incedeus  E.  H. 
Helcnra  caudata  E.  H. 


Beptiles  and  Amphibia. 

Orthodactylus  linearis  E.  H. 
Antipus  bifiduB  E.  H. 

iiexiloquus  E.  H. 
Stenodactylus  curvatus  E.  H. 
Axaclmichnus  dehiscens  E.  H. 
Isocampe  strata  E.  H. 
Typopus  abnormis  E.  H. 

gracilis  E.  H. 
Anislchnus  [C.  H.  H.]  deweyanus  E.  H. 
gracilis  E.  H. 
gracilior  E.  H. 
Comptichnus  obesus  E.  H. 

n.  sp.  C.  H.  H. 


Batrachians. 


CheJoniana. 


Cheirotheroides  pilulatus  E.  H. 
Shepardia  palmipes  E.  H. 
Lagunculipes  latus  E.  H. 
Selenichnus  falcatus  E.  H. 

breviuBculus  E.  H. 
Exocampe  arcta  E.  H. 

ornata  E.  H. 

minima  E.  H. 

Helcura  surgens  E.  H. 

anguinea  E.  H. 
Amblypus  dextratus  E.  H. 


Sexapod  Arthropoda. 


Giammepus  erismatus  E.  H. 
Acantbichnus  cursorius  E.  H. 

alternans  E.  H. 

alatus  E.  H. 

anguineus  E.  H. 

trilinearis  E.  H. 

punctatua  E.  H. 

rectilinearis  E.  H. 

divaricatus  E.  H. 

saltatorlus  E.  H. 
Bifurculipes  laqueatus  E.  H. 

soolopendroideus  E.  H. 


Bifurculipes  curvatus  E.  H. 

elachistotatus  E.  H. 
Copeza  triremis  E.  H. 

propinquata  E.  H. 
punctata  E.  H. 
cruscularis  E.  H. 
Hexapodichnus  magnus  E.  H. 
horrens  E.  H. 
Conopsoides  larvalis  E.  H. 

ourtus  E.  H. 
Harpipes  oapillaris  E.  H. 
Sagittarius  alternans  E.  H. 


Harpagopus  dubius  E.  H. 
Stratipes  latus  E.  H. 
Hamipes  didactylus  E.  H. 
Saltator  blpedatus  E.  H. 
caudatus  E.  H. 
Halysichnus  laqueatus  E.  H. 

tardigradus  E.  H, 
Cunicularius  retrahens  E.  H. 


Inferior  Arthropods,  including  larval  forms  and  worms, 

Spbferipes  larvalis  E.  H. 

magnus  E.  H. 
Lunula  obscura  E.  H. 
Ptericbnus  centipes  E.  H. 
Unisulcus  marshi  E.  H. 

intermedius  E.  H. 

minutus  E.  H. 

magnus  C.  H.  H. 


PALEONTOLOGY. 


403 


Bisulcns  iindulatus  E.  H. 
Trisnlons  laqueatiis  E.  H. 
Cocliloa  archimedea  E.  H. 


Hopliobnus  equus  E.  H. 

polodruB  E.  H. 
^nigmichnus  multiformis  E.  H. 


MoUuaca. 


Incertce  sedis. 


CoohliohnuB  anguineus  E.  H. 
two  n.  sp. 


Grammiolmus  alpha  E.  H. 
Ampelichuus  sulcatus  E.  H. 
Climacodichnus  corrugatus  E.  H. 


Of  lower  arthropods  and  worms  there  may  be  half  a  dozen  new  species  and  two 
new  genera. 


Summary : 


Marsupial 1 

Pachydactylous  birds 17 

Leptodactylous  birds 18 

Dinosaurs 28 

Reptiles  and  amphibia 27 

Batrachians 16 

Chelonians 6 


Hexapod  arthropods 24 

Lower  arthropods  and  worms 16 

MoUusca 6 

IncertsB  sedis 6 

Total 165 


The  class  of  Birds  is  still  retained  for  convenience,  although  the  bones  found  in 
the  west  seem  to  point  to  reptiles  as  most  probably  the  animals  thus  designated.  It 
is  still  a  fact  that  such  special  reptilian  characteristics  as  would  be  exhibited  in  walk- 
ing are  absent  in  the  genera  Brontozoum  and  Grallator,  while  those  creatures  called 
Dinosaurs  are  thus  referred,  either  because  of  the  marks  of  front  feet,  heels  to  the 
hind  feet,  or  of  tails.  The  bird  group  is  also  characterized  by  long  legs,  while  most 
of  the  Dinosaurs  had  short  legs,  as  indicated  by  their  numerous  steps.  I  do  not 
change  the  reference  of  a  group  to  Chelonians,  though  it  is  not  satisfactory. 

The  Arthropoda  are  most  likely  to  be  referred  to  the  lower  classes;  yet  the 
presence  of  only  6  feet  in  the  impressions  leads  us  to  speak  of  them  as  Hexapods. 
They  may  not  be  true  insects,  but  larval  forms,  requiring  further  investigation 
before  satisfactory  references  can  be  made  out.  Further  statement  of  the  reasons 
for  referring  various  imprints  to  their  lowly  owners  would  involve  a  discussion  of 
the  third  part  of  the  subject,  which  can  not  be  undertaken  now.^ 

It  will  be  proper  to  state  a  few  facts  about  museums  and  localities  before  describ- 
ing the  new  species. 

THE   AMHEBST  MUSEUM. 

A  few  slabs  have  been  added  since  1865,  and  the  arrangement  of  the  rooms  has 
not  been  changed  since  the  printing  of  the  catalogue.  One  slab  shows  a  Brontozoum 
with  two  toes  on  one  foot  and  three  upon  the  other,  as  if  the  owner  had  lost  a  toe  by 


'  Of  modern  authors,  A.  Gt.  Nathorst  has  treated  of  the  invertebrate  tracks  most  fully  in  his 
M^moire  sur  quelques  traces  d'animaux  sans  vert^br^,  etc.,  et  de  leur  port^e  pal^ontologique,  1880. 
His  bibliography  notices  several  American  authors,  but  he  has  evidently  not  seen  the  Ichnology  of 

Massachusetts. 


404  GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

fighting  or  by  accident.  After  the  discovery  of  Apaticlmus  holyohensis,  I  was  able  to 
point  out  several  illustrations  of  the  new  species  at  Amherst,  which  had  been  over- 
looked in  the  preparation  of  the  Ichnology  and  Supplement. 

museum:  at  south  hadlbt. 

The  Mount  Holyoke  Seminary  and  College  has  taken  great  interest  in  Ichnology 
and  possesses  an  admirable  collection.  Among  the  more  important  ones  are  the  type 
specimens  of  Apatichnus  holyohensis  and  of  six  or  eight  new  species  from  Wethers- 
field  Cove,  besides  Anotncepus  cuneatus  and  A.  isodaotylus  from  the  Dickinson  quarry 
at  South  Hadley.  The  data  for  improved  descriptions  of  Brontozoum  divaricatum 
and  Plectropterna  elegans  are  present,  as  well  as  long  rows  of  Otozoum  moodii,  Bronto- 
zoum  giganteum,  and  B.  approximatum.  The  slabs  occupy  a  large  room  in  the  base- 
ment of  the  Lyman  WiUiston  Hall,  while  smaller  specimens  have  been  placed  in  the 
adjoining  apartment. 

The  institution  possesses  several  slabs  from  the  Dickinson  quarry,  about  a  mile 
north  from  the  buildings.  These  are  composed  of  a  hard  sandstone  which  preserves 
the  impressions  and  casts  with  unusual  distinctness.  The  marks  of  the  heels  of  the 
hind  feet,  the  front  feet,  and  the  tails  of  Anomcepus  are  very  plentiful.  About  sixty 
species  of  Ichuozoa  are  placed  upon  these  tables,  and  a  careful  description  of  every 
slab  exists  in  the  manuscript  form. 

This  catalogue  is  like  the  one  prepared  by  myself  in  1865  for  the  Amherst 
collection  and  printed  in  the  Supplement. 

Of  the  above  species,  tlie  JEnigmichnus  multiformis  is  certainly  the 
marking  of  a  diifting  tree  whose  roots  or  branches  trailed  in  lines  strictly 
parallel  along  the  bottom,  these  lines  often  changing  to  a  row  of  dots  or  a 
moniliform  line  from  the  rising  and  sinking  of  the  plant  with  the  waves. 
These  parallel  lines  cover  a  space  several  feet  wide  and  could  hardly  be 
formed  by  any  animal.  Further,  Professor  Hitchcock  has  omitted  a  sec- 
tion of  fish-tracks  given  in  the  Ichnology  with  a  genus  Ptilichnus,  or  "  fin- 
track,"  thought  by  President  Hitchcock  to  be  the  marks  of  the  fins  of  fishes. 
The  markings  are  very  uncertain  and  may  well  be  withdrawn  from  the  list. 
I  have,  however,  found  in  the  collection  many  fine,  thin  slabs  with  a  curious 
marking  upon  them,  which  bear  the  name  "  Aroid  Plants,  Sunderland"  in 
President  Hitchcock's  writing,  but  about  which  he  seems  to  have  published 
nothing.  The  resemblance  of  these  markings  to  the  markings  which  would 
be  made  by  the  ventral  fin  spines  of  a  fish  drifting  slowly  backward,  and 
by  a  few  slight  rapid  strokes  stemming  the  current  at  regular  intervals,  is 
certainly  sti'iking. 


PALEONTOLOGY.  405 

REPTILES. 

Megadactylus  Owen. 
Megadact\lus  polyzelus  E.  Hitchcock,  jr. 

1858.  "Bones  of  a  reptile."    Jeffries  Wyman.    Ichnology  of  New  England,  p.  186. 
1863.  Megadactylus  polyzelus.     E.  Hitchcock,  jr.     Supplement  to  Ichnology  of 

New  England,  p.  39. 
1871.  Megadactylus  polyzelus.    E.  D.  Cope.     Synopsis  of  the  extinct  Eeptilia  and 

Aves  of  the  United  States:   Trans.  Am.  Phil.  Soc,  Vol.  IV,  p.  122a, 

PI.  XIII. 
1884.  Amphisaurus  [Megadactylus).    O.  C.  Marsh.    Am.  Jour.  Sci.  Sup.  XXVII, 

p.  338. 
1889.  Anchisaurns.     O.  0.  Marsh.    Am.  Jour.  Sci.  Sap.  XXXVII,  p.  331. 

This  rare  and  remarkable  fossil  has  had  a  peculiar  history.  The  bones 
■were  thrown  out  by  a  bjast  in  excavating-  a  well  for  the  casting  of  a  big  gun 
at  the  water  shops  of  the  United  States  Armory,  in  the  south  part  of  Spring- 
field, and  only  a  part  of  the  skeleton  was  preserved  and  presented  to  Presi- 
dent Hitchcock.  These  bones  were  first  studied  by  Jeffries  Wyman,  and 
determined  by  him  to  be  those  of  a  reptile.  His  letter  contains  many  acute 
observations.  He  notes  the  hollowness  of  the  bones,  a  peculiarity  suggest- 
ing birds  and  pterodactyls,  but  decides  against  the  reference  of  the  bones 
to  either  of  these.  The  unequal  length  of  the  toes  suggests  a  jumping 
animal. 

The  bones  were  then  carried  to  London  by  Dr.  Edward  Hitchcock  and 
submitted  to  Prof.  Richard  Owen,  who  determined  them  to  be  those  of  a 
Saurian  reptile,  but  added  otherwise  nothing  to  the  diagnosis  of  Wyman.' 
His  one  sentence  concerning  the  bones  is  interesting.  They  belong  to  "a 
Saurian  reptile  with  an  unusually  thin  wall  of  bone  in  the  limb  bones, 
which,  however,  might  have  been  occupied  by  unossified  cartilage,  as  in 
the  young  crocodile  and  turtle;  but  if  they  were  filled  with  oil  or  light 
maiTow,  it  would  point  to  a  course  of  development  toward  pterodactyls  or 
birds.  The  phi-ase  is  purely  hypothetical,  and  I  mean  to  express  no  more 
than  a  degree  of  resemblance,  supposing  marrow  and  not  gristle  to  have 
filled  the  large  cavities."  Later,  Dr.  Hitchcock  worked  out  the  bones  with 
a  graver  and  named  the  animal  in  the  article  quoted. 

The  specimen  was  then  carefully  studied,  figured,  and  described  by 


406  GEOLOGY  OP  OLD  HAMPSHIEE  COUifTY,  MASS. 

Cope,  who  refeiTed  it  to  the  Triassic  Dinosauria  and  called  special  attention 
to  the  very  peculiar  ischium. 

In  1876  I  earned  the  bones  to  New  Haven,  where  they  were  studied 
by  Professors  Huxley  and  Marsh,  and  casts  of  them  were  taken  by  the 
latter.  Professor  Huxley  was  inclined  to  think  them, identical  T^ith  one  or 
other  of  two  genera  of  reptiles  found  by  Stutchbury  in  the  Trias  near 
Bristol,  England,  and  preserved  in  the  museum  of  that  city — Paleosaurus 
and  Thecodontosaurus — but  because  of  some  loss  or  change  of  labels  it 
was  not  possible  to  tell  which  of  the  bones  preserved  in  the  museum  should 
be  called  by  the  first  of  these  names  and  which  by  the  second.  At  a  later 
time  Professor  Marsh  gave  a  new  name  to  the  genus,  as  indicated  in  the 
synonymy  above,  and  still  later,  finding  that  this  name  had  been  preoccu- 
pied, he  gave  the  fossil  another  name. 

The  bones  include  a  nearly  perfect  foot,  the  ischium,  femur,  caudal  ver- 
tebrae, and  many  imperfect  fragments.  A  few  very  imperfect  fragments  of 
the  bones  of  a  similar  species  were  found  earlier,  and  are  preserved  in  the 
museum,  but  without  locality;  and  I  have  found  many  imperfect  fragments 
of  bone  in  the  indurated  sandstone  of  the  contact  zone  of  the  easternmost 
volcanic  core  in  Belchertown.  This  induration  has  prevented  the  percola- 
tion of  water,  which  has  doubtless  carried  away  many  bones  formerly 
embedded  in  these  coarse  sandstones. 


CHAPTER    XIII. 

TRIASSIC  ERUPTIVE  ROCKS. 


HISTORICAL. 


As  early  as  1815  President  Hitchcock  described  the  "Basaltick  Col- 
umns" of  Titan's  Piazza  in  the  first  volume  of  the  North  American  Review.' 
He  gave  the  "greenstone"  only  a  word  in  the  Greology  of  Deerfield,^  not 
distinguishing  it  from  the  hornblende-schist  of  West  Northfield.  It  is 
described  at  some  length  in  the. Geology  of  the  Connecticut^  as  "secondary 
greenstone,"  without  reference  to  its  mineralogical  constitution.  He  notes 
that  it  is  more  amygdaloidal  in  its  upper  portion,  describes  the  contact  of 
the  upper  sandstone  on  the  trap  in  Sunderland  and  Deerfield,  and  interprets 
the  fault  at  the  mouth  of  Fall  River,  described  below  (p.  437),  as  a  repe- 
tition of  the  trap. 

In  his  earlier  report  upon  the  Geology  of  Massachusetts*  he  gives  a 
very  full  account  of  the  "greenstone,"  touching  upon  its  lithological  pecul- 
iarities, its  distribution,  mineral  contents,  and  origin,  an  account  which  has 
lost  httle  of  its  value,  and  which,  because  of  its  great  length,  I  shall  only 
briefly  summarize  here,  as  the  main  points  are  cited  beyond.  He  now 
considers  the  "greenstone"  to  be  made  up  of  feldspar  and  hornblende,  and 
remarks  that  he  has  not  met  with  a  genuine  and  distinct  dike  of  trap  in 
the  sandstone. 

In  the  later  edition  of  the  above  work  (1835),  and  in  the  Final  Report,^ 
the  same  account  is  reprinted  almost  verbatim,  the  only  additional  informa- 
tion given  relating  to  the  small  dikes  in  the  gneiss  on  the  east  of  the  sand- 
stones. An  inspection  of  the  maps  accompanying  the  above  reports  shows 
clearly  that  the  trap  was  laid  down  most  accurately  on  the  map  of  1823, 


'  Page  337. 

!2  Am.  Jour.  Soi.,  Ist  series,  Vol.  I,  1819,  p.  105. 

3  Am.  Jour.  Sci.,  1st  series,  Vol.  VI,  1823,  p.  44. 

"Geol.  of  Mass.,  Amherst,  1833,  p.  404. 

^Geol.  of  Mass.,  Final  Kept.,  Amherst,  1841,  p.  640. 


407 


408  GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

especially  as  regards  the  Deerfield  bed,  and  that  with  the  poor  maps  and 
the  small  scale  used  the  delineation  became  more  and  more  inaccurate. 
Upon  the  map  of  1844  the  Mount  Tom  range  is  represented  much  more 
accurately,  a  posterior  range  is  given  in  West  Springfield,  and  three  long 
patches  of  "trap  tufa  and  tufaceous  conglomerate"  are  laid  down.  Upon 
the  map  in  the  Ichnology,  1857,  a  further  advance  is  made  by  showing  that 
the  Holyoke  range  consists  of  two  bands  of  trap  with  a  narrow  intervening 
band  of  sandstone.  The  section  through  Norwottock  on  the  border  of  the 
above  map  is  incorrectly  colored  to  indicate  three  bands  of  trap ;  the  south- 
em  band  should  receive  the  color  of  the  "trap  tufa."  Furthermore,  in  all 
the  copies  of  the  work  I  have  seen  the  trap  tufa  has  the  same  color  as  the 
crystalline  rocks  upon  the  borders  of  the  map,  while  in  the  legend  a  deeper 
shade  of  the  color  is  assigned  to  it.  This  error  has  perpetuated  itself  in  a 
curious  way.  Upon  the  small  geological  map  attached  to  the  map  of 
Hampshire  County  of  H.  F.  Walling  (1858)  a  pink  band  of  crystalline 
rocks  is  made  to  run  across  from  Belchertown  to  the  river  south  of  the 
Holyoke  range.  The  map  is  said  to  be  "by  Edward  Hitchcock."  One 
may  infer,  I  think,  that  he  had  very  little  to  do  with  it. 

In  the  small  map  appended  to  Reminiscences  of  Amherst  College 
(1863),  President  Hitchcock  gave  his  final  results  regarding  the  rocks  in 
question.  He  now  makes  the  Holyoke  range  a  single  broad  area  of  trap 
extending  east  to  overhang,  with  undiminished  width,  the  northern  of  the 
Belchertown  ponds,  and  lays  down  two  great  areas  in  Pelham,  the  one 
made  out  by  coloring  as  trap  the  whole  area  between  the  two  occurrences 
detailed  below,  and  the  other  based  upon  the  area  of  great  bowlders  east  of 
Amethyst  Brook. 

The  geological  map  of  Prof.  C.  H.  Hitchcock  in  Walling's  Atlas  of 
Massachusetts  (1871)  gives  a  posterior  bed  in  the  eastern  half  of  the 
Holyoke  range  and  the  northern  part  of  the  Mount  Tom  range,  presenting 
thus  the  best  results  of  his  father's  work. 

In  1875  Prof.  E.  S.  Dana  presented  to  the  American  Association  the 
preliminary  results  of  studies  upon  the  Triassic  diabases,  undertaken  by 
himself  and  Mr.  Gr.  W.  Hawes,  and  in  the  same  year  Mr.  Hawes  printed 
a  series  of  analyses  of  these  rocks,  including  one  from  Mount  Holyoke. 
Although  in  the  main  devoted  to  the  Connecticut  rocks,  these  studies 
reached  results  applicable  to  this  area,  viz:    the  greater  freshness  of  the 


TEIASSIO  ERUPTIVE  ROCKS.  409 

diubuso  from  the  o-iieiss,  its  composition  of  pyroxene  find  the  triclinic  feld- 
spars labradorite  and  anorthite,  and  the  rare  presence  of  oHviue.  By 
companson  oi'  the  altered  with  the  unaltered  varieties,  it  was  seen  that  this 
alteration  has  not  been  attended  by  further  oxidation  of  the  iron,  and 
therefore  could  not  have  been  accomplished  by  any  surface  action,  since 
the  oxidation  of  protoxide  of  iron  is  one  of  the  chief  causes  of  surface 
alteration,  while  in  this  case  one  mineral  containing-  protoxide  has  been 
changed  into  another  protoxide  mineral.  It  would  therefore  seem,  certain 
that  the  alteration  took  place  at  the  time  of  ejection,  as  had  been  urged  by 
Professor  Daua.^ 

Later,  Mr.  Hawes^  made  a  separation  (by  Thoulet's  solution)  and 
analysis  of  the  feldspars  in  diabase  from  New  Jersey,  determining  them 
to  be  labradorite  and  andesite.  He  further  calculates,  on  the  basis  of 
analyses  in  his  preceding  paper,  the  mineral  composition  of  the  "West 
Rock  dike"  near  New  Haven,  finding  it  to  contain  the  feldspars  anorthite, 
albite,  and  orthoclase,  with  augite,  titanic  iron,  magnetite,  and  apatite. 

Professor  Dana,^  in  a  very  pungent  critique  of  this  paper,  objects  that 
the  anorthite  came  from  a  later  transverse  (east-west)  dike  in  the  West 
Rock  dike,  and  so  can  not  be  combined  with  the  gross  analysis  of  the  latter, 
as  was  done  by  Mr.  Hawes. 

In  1882  the  author  published  a  paper,  mainly  mineralogical,  on  the 
Deei-field  dike,*  in  which  the  contact  metamorphism  on  the  sandstone  below 
and  the  amygdaloidal  character  of  the  trap  sheet  in  its  upper  portion  and 
the  unaltered  condition  of  the  sandstone  above,  which  is  molded  into  all 
the  interstices  of  the  trap,  are  adduced  in  support  of  the  view  that  this 
trap  body  is  a  contemporaneous  sheet  and  not  a  true  dike. 

The  presence  of  a  beautiful  fault  at  the  mouth  of  Fall  River  was  noted. 
The  proofs  of  its  existence  would  seem  to  have  been  given  with  too  much 
brevity,  as  they  failed  to  convince  the  author  of  the  paper  to  be  mentioned 
next,  and  they  will  be  given  more  fully  in  the  sequel. 

In  the  following  year  appeared  a  very  valuable  article,  by  Prof.  W.  M. 
Davis,^  on  the   "  Triassic  trap  rocks  of  the  eastern  United   States,"  spe- 

'  Am.  Jour.  Sci.,  3d  series,  Vol.  VI,  p.  104. 

=  Proc.  U.  S.Nat.Mu8.,  1881,  p.  129. 

3  Am.  Jour.  Sci.,  3d  series.  Vol.  XXII,  p.  230. 

•■Am.  Jour.  Sci.,  3  series,  Vol.  XXIV,  1882,  p.  195. 

6 Bull.  Comp.  Zool.  Harvard  Coll.,  Vol.  VII,  p.  251. 


410       GEOLOGY  OP  OLD  HAMPSHIEE  COUNTY,  MASS.  ' 

cially  valuable  because  of  the  reproduction  of  all  the  sections  and  dia- 
grams explaining  earlier  views  of  the  structure  of  the  trap  ridges  and  of 
the  full  discussion  of  previous  theories.  Of  the  abundant  original  observa- 
tions only  two  groups  relate  to  the  Massachusetts  area — one  to  the  Turners 
Falls,  the  other  to  the  Mount  Tom  region.  He  considers  part  of  the  trap 
masses  to  be  contemporaneous  beds  and  part  to  be  true  dikes,  but  adduces 
only  cases  under  the  first  category  from  Massachusetts.  The  Deerfield 
bed  he  makes  to  be  three  beds,  echeloned  one  posterior  to  the  other.  I 
have  found  it  to  be  a  single  bed,  faulted  several  times  at  the  north  end,  as 
will  be  detailed  below. 

In  1892  the  author  published  a  preliminary  paper  on  the  quarry  lor 
road  material  at  Greenfield  and  described  the  under-rolling  of  the  trap  and 
the  formation  of  breccia-like  beds.^ 

In  the  summer  of  1896  the  author  presented  a  paper  before  the  Greolog- 
ical  Society  of  America  entitled,  "  Diabase  pitchstone  and  mud  inclosures 
of  the  Triassic  trap  of  New  England."^  The  paper  explains  the  manner  in 
which  water  and  mud,  frothing  up  into  the  trap  from  the  sea  bottom  over 
which  it  was  flowing,  produced  pitchstone  and  shattered  the  mixture  and 
recemented  it  with  an  aqueous  deposit  of  albite  and  bisilicates.  There 
was  also  described  the  sweeping  of  fine  mud  out  over  the  surfacQ  of  the 
Holyoke  sheet  by  convection  cuiTents  and  its  under-rolling  to  form  the 
base  of  the  bed. 

THE    THREE    EPOCHS   OF    ERUPTIVE  ACTIVITY;    GETSTERAXi  ACCOUDST. 

1.  The  rapid  transgression  of  the  Triassic  waters  over  the  area  had 
spread  a  great  thickness  of  coarse  granitic  debris  when  two  fissures  allowed 
the  passage  of  great  volumes  of  basic  lava  to  form  the  Deerfield  and  Holyoke 
diabase  sheets.  Sedimentation  went  on  undistm-bed.  Generally  the  first 
layers  spread  on  the  surface  of  the  sheets  were  the  same  or  nearly  the  same 
as  those  on  which  the  trap  rests.  In  the  Holyoke  bed  one  can  see  in  small 
degree  the  influence  of  the  shallowing  of  the  waters,  and  the  beds  above 
are  of  finer  grain.  The  fissure  for  the  Deerfield  bed  must  have  been 
beneath  the  present  outcrop  or  the  lava  must  have  come  from  the  dikes 
in  the  gneiss  along  the  eastern  border  of  the  basin.     The  fissure  of  the 

'Am.  Jour.  Sci.,  3d  series,  Vol.  XLVI,  p.  146. 

3  Bull.  Geol.  Soc.  America,  Vol.  VIII,  1897,  pp.  59-96. 


THREE  EPOCUS  OF  TltlASSIG  ERUPTION.  41 1 

Holyoke  bed  was  probably  a  mile  soiitli  and  east  of  the  present  outcrop, 
along-  the  line  of  later  trap  intrusions.  The  beds  slightly  baked  the  sand- 
stones below  and  are  amygdaloidal  and  ropy-surfaced  above.  They  often 
took  up  great  quantities  of  the  rock  over  which  they  flowed,  and  the  fact 
and  direction  of  flow  are  shown  by  the  marked  difference  between  these 
fragments  and  the  subjacent  rock.  Much  sedimentary  material  is  in  places 
kneaded  into  the  surface  layers  of  the  trap — either  before  it  became  solid 
or  in  a  breccia  layer — and  is  then  carried  underneath  by  the  under-rolling 
of  the  solid  and  yet  plastic  front  of  the  advancing  sheet. 

2.  A  great  core,  representing  a  second  epoch  of  volcanic  activity,  now 
forms  Little  Mountain,  which  lies  between  Mount  Tom  and  the  river  below 
Smiths  Ferry,  and  from  it  flowed  a  thin  but  double  sheet  south  beyond  the 
limit  of  the  State  and  north  at  least  to  the  river,  a  half  mile  south  of  the 
Holyoke  gap. 

3.  Immediately  following  this  came  an  explosive  outburst  which  spread 
tuff  south  to  Holyoke  and  east  across  the  whole  basin  to  Belchertown. 
East  of  the  river  this  rests  on  arkose;  west,  on  the  upper  trap  sheet.  Its 
masses  are  largest  (3  feet  in  length)  at  Smiths  Ferry  and  decrease  slowly 
east  and  south. 

The  results  of  the  last  period  of  volcanic  activity  appear  in  a  line  of 
crater  tln-oats  and  short  intrusive  dikes  extending  from  the  river  to  the  east 
edge  of  the  basin,  parallel  to  and  a  mile  south  of  the  Holyoke  range.  Two 
are  of  very  large  size  and  one  is  a  diabase  full  of  quartz  and  feldspar 
grains.  They  make  a  small  angle  with  the  tuff  sheet,  so  that  some  lie 
south  and  some  north  of  it  and  some  penetrate  it  in  whole  or  part. 

DIABASE  DIKES  AISTD  STOCKS  IN  THE  GNEISS  EAST  OP  THE  TRIAS. 

A  series  of  small  dikes  appear  in  the  gneiss  east  of  and  a  short  distance 
from  the  sandstones.  I  do  not  find  reason  to  consider  them  continuous  over 
so  long  a  distance  north  and  south  as  they  would  appear  to  be  from  Perci- 
val's  excellent  map  of  their  distribution  in  Connecticut,  nor  does  any  trace 
of  the  similar  western  line  of  dikes  marked  by  him  extend  northward  into 
Massachusetts. 

They  are  typical  diabases,  much  fresher  and  of  finer  grain  than  the  large 
masses  in  the  sandstones,  but  scarcely  offering  any  appreciable  distinction 
from  the  finer  grades  of  the  latter.     On  their  borders,  however,  and  in  small 


412  GEOLOGY  OP  OLD  HAMPSHIRE  COUNTY,  MASS. 

dikes  from  a  half  inch  to  an  inch  across,  which  are  at  times  abundant  in  the 
gneiss,  they  reach  a  degree  of  fineness  never  seen  in  the  central  dikes,  and  are 
in  part  or  wholly  made  up  of  glass,  and  contain  olivine,  which  allies  them  to 
the  newer  outflows  in  the  main  valley. 

1.  The  most  northerly  of  these  dikes  cuts  gneissoid  rocks  on  the  east 
bank  of  the  Coimecticut,  a  few  rods  below  the  mouth  of  Millers  River.  The 
dike  is  about  3  feet  wide  and  runs  south  from  the  water's  edge  and  disap- 
pears in  a  short  distance  beneath  the  terrace  sands.  It  is  a  compact,  very 
fresh,  dark-gray  rock,  with  few  porphyritic  feldspars  1  ™™  long  and  extinc- 
tion 21°  on  either  side  of  the  twimiing  suture,  the  smaller  feldspar  0.12™™, 
the  light-yellow  augite  peculiarly  granular  and  without  crystalhne  outline. 
Magnetite  is  veiy  abundant.  This  occurrence  is  cited  by  President  Hitch- 
cock in  his  first  report,^  and  incorrectly  assigned  to  Erving  in  the  Final 
Report.^ 

2.  The  next  dike  is  intruded  along  the  bedding  of  the  gneiss,  in  the 
vertical  wall  which  forms  the  north  bank  of  Millers  River,  east  of  the  bi'idge 
in  the  village  of  Millers  Falls.  As  the  gneiss  has  a  low  dip  to  the  west, 
the  dike,  which  is  about  7  feet  wide,  reaches  the  water's  edge  just  west 
of  the  bridge,  where  its  crossing  the  stream  gave  rise  to  the  falls  from 
which  the  village  gets  its  name.  The  rock  was  not  distinguishable  in  thin 
sections  from  that  of  the  preceding  occurrence. 

3.  The  next  outcrop  was  a  knob  of  remarkably  fresh  ice-worn  rock 
exposed  in  the  cutting  made  in  1881  in  the  relocation  of  the  raih-oad  tracks 
a  few  rods  south  of  the  Millers  Falls  station.  The  diabase  was  exposed 
in  a  rounded  ice-worn  boss,  10  or  12  feet  across,  without  contacts.  A  few 
yards  to  the  east,  and  2  yards  lower,  gneiss  was  exposed,  in  which  rock 
the  diabase  was  doubtless  intruded. 

4.  President  Hitchcock  notes  greenstone  in  Montague,  on  the  west 
border  of  gneiss,  2  miles  northeast  of  the  meetinghouse.  It  separates  in 
plates  directed  east  and  west  and  standing  vertical.^  This  locality  is  beside 
the  railroad,  a  mile  south  of  Millers  Falls,  south  of  J.  Hannegan's  house. 
A  ridge  325  feet  long,  82  feet  wide,  and  20-30  feet  high  nms  N.  35°  E., 
surroimded  by  the  terrace  sands.  The  last  three  outcrops  may  form  parts 
of  one  long  dike. 

1  Geol.  of  Maes.,  1835,  p.  417. 

^Ibid.,  1841,  p.  648. 

8 Geol.  Mass.,  Final  Report,  1841,  p.  648. 


DIABASE  DIKES  AND  STOCKS  IN  THE  GNEISS.  413 

The  above  dikes  near  Millers  Falls  are  of  ideal  freshness;  very  rarely 
one  sees  in  a  single  large  feldspar  a  slight  central  clouding,  like  a  delicate 
ileck  of  cotton.  They  are  rather  light-gray,  extremely  tough,  and  yet  brittle 
as  glass.  The  constituents  are  of  exactly  the  average  dimensions  given  in 
the  general  description  of  the  diabase,  page  438.  The  augite  is  yellow  to 
amethystine,  dichroic,  and,  although  perfectly  fresh,  it  appears,  from  the 
strong  cleavage  and  abundant  inclusions,  only  translucent,  and  looks  in  the 
slide  as  if  a  quantity  of  pulverized  material  had  been  spread  over  the  network 
of  feldspars.     This  enables  one  to  distinguish  it  from  other  occurrences. 

5.  Across  Montague  and  Leverett  no  other  outcrops  occur.  In  Pelham, 
on  the  south  side  of  the  Shutesbmy  road,  west  of  where  it  crosses  Amethyst 
Brook,  a  great  outcrop  of  the  same  fine-grained  diabase  occurs  in  the  actin- 
olitic  quartzite.  It  is  a  squarish  mass  about  82  by  130  feet,  its  longest 
diameter  north  and  south.  Following  the  stream  up  from  this  point  to  where 
a  brook  comes  in  from  the  north,  one  finds  a  great  number  of  large  bowlders 
of  diabase  in  its  bed,  some  of  large  size.  There  is  probably  a  considerable 
bed  in  the  pasture  a  few  rods  east  of  the  junction  of  the  brooks.  Further, 
the  fine  amethysts  which  occur  as  rolled  specimens  in  the  bed  of  the  brook 
probably  indicate  the  presence  of  diabase  here.  A  mile  northeast  also,  in 
the  deep  brook  gorge  north  of  Ward's  quarry,  occur  a  great  number  of 
very  large  diabase  bowlders,  as  well  as  much  farther  east  in  the  eastern 
portion  of  the  town,  along  the  roads  that  run  down  from  Pelham  Center 
to  the  Swift  River  Valley. 

6.  If  the  line  connecting  the  above  outcrops  in  Pelham  be  prolonged 
N.  40°  E.  into  Shutesbury,  it  strikes  a  great  outcrop  of  diabase  at  the  point 
where  it  crosses  the  road  going  north  from  Pelham  Center,  ojaposite  the 
house  of  W.  Thrasher.  It  is  exposed  with  a  length  of  25  rods  and  a  width 
of  75  feet,  and  runs  N.  40°  E.  It  is  a  fine  to  very  fine,  very  fresh  diabase 
of  the  common  structure,  the  finest-grained  portion  showing  a  globulitic 
groundmass  as  inclusion  in  the  feldspars,  and  small  olivines. 

7.  If  the  line  be  prolonged  N.  40°  E.  across  to  the  river  road,  another 
outcrop  of  diabase  occurs  on  the  hillside  northwest  of  the  house  of  S.  H. 
Stowell.  An  inspection  of  the  map  will  show  that  all  the  above  series  of 
outcrops  occur  along  a  northeast  fault  which  has  opened  the  entrance  to 
the  upland  basin  of  Pelham  and  caused  the  sharp  southern  slope  of  Mount 
Hygeia. 


414  GEOLOGY  OF  OLD  HAMPSHIEB  COTJNTT,  MASS. 

8.  Again,  where  the  road  east  from  Pelham  post-office,  halfway  down 
the  hill,  turns  from  south  to  southeast,  a  large  outcrop  of  trap  occurs  on 
the  north  side  of  the  road. 

9.  Groing  about  115  rods  on  the  first  western  road  running  south  from 
the  West  Village  of  Pelham,  and  turning  east  into  the  woods,  one  finds  an 
east-west  vertical  dike,  at  one  place  nearly  6  feet  thick,  but  running  west 
with  a  thickness  of  only  1  foot,  which  sends  off  many  small  branches  into 
the  gneiss,  one  of  which  furnished  the  material  for  the  study  on  page  416. 

10.  On  Coys  Hill,  in  the  southeast  part  of  Ware,  north  of  the  point 
wnere  the  road  crosses  the  town  line,  a  vertical  dike  of  diabase  occurs  in 
the  high  bluff  northeast  of  the  road  across  the  ravine.  It  is  horizontally 
bedded,  50  feet  wide,  and  can  be  followed  a  half  mile  south,  first  with  strike 
N.  40°  E.,  then  swinging  round  to  N.  30°  E.,  when  it  crosses  the  town  line 
into  Worcester  County.  It  is  fine-grained  and  is  beautifully  exposed,  with 
its  attendant  swarm  of  small  dikes  in  the  adjacent  gneiss.  It  is  now  quar- 
ried for  road  material  just  east  of  the  station,  where  it  is  5  rods  wide. 

11.  A  great  accumulation  of  bowlders  of  the  aphanitic  diabase  in 
Belchertown,  north  of  the  schoolhouse,  near  E.  Willis's,  another  near  the 
center  of  Wales,  and  another  in  the  northeast  of  Belchertown  indicate  in 
each  case  the  proximity  of  an  area  of  the  rock  covered  by  drift  deposits. 

12.  About  650  feet  east  of  the  house  of  J.  Bardwell,  near  the  west  line 
of  Belchertown,  occurs  an  isolated  outcrop  of  trap,  forming  a  hill  of  great, 
broken  masses  of  the  rock.  It  is  about  33  by  100  feet,  and  gneiss  occurs 
in  the  near  vicinity  on  every  side,  though  the  immediate  contact  could  not 
be  observed.  The  rock  is  the  dark  bluish-gray  aphanitic  variety  common 
in  the  gneiss. 

13.  Just  south  of  Flint's  quarry,  in  Monson,  a  heavy  dike  of  trap  is 
cut  through  by  the  quarry  railroad.  It  can  be  followed  but  a  short  distance 
to  the  north,  when  it  is  cut  off  by  a  fault  and  offset  to  the  east,  and  its  con- 
tinuation, with  the  evidence  of  the  faulting,  can  be  found  in  the  south  bluff 
of  the  ridge  next  east.  From  this  point  it  can  be  followed  northeast  more 
than  half  a  mile,  till  it  disappears  beneath  the  sands  in  the  Monson  Valley. 
It  is  about  410  feet  wide.  The  small  dike  next  described  is  apparently  an 
offshoot  from  it,  and  the  great  number  of  trap  bowlders  found  over  the  high 
ground  in  the  east  part  of  Monson  are  clearly  derived  from  it,  and  their 
distribution  makes  it  plain  that  the  dike  extends  much  farther  northeast 
and  southwest  than  can  be  seen.     It  is  now  quamed  for  road  material. 


DIABASE  DIKES  AND  STOCKS  IN  THE  GNEISS.  415 

14.  A  vertical  dike  of  black,  fine-grained,  horizontally  jointed  diabase 
runs  east  and  west  tlirougli  the  great  quarry  at  Monson.  It  is  nowhere 
more  than  16  inches  wide,  and  as  it  goes  upward  it  has  a  curious  warp  to 
the  south.  It  sends  oflf  many  small  dikes,  which  are  specially  discussed  in 
the  next  section  below  (p.  416). 

16.  Farther  south  in  Monson,  in  the  crest  of  the  bluff  west  of  S.  Mac- 
intosh's house,  is  a  dike  of  similar  rock,  50  feet  wide,  running  N.  65°  E., 
which  can  be  traced  for  some  distance  in  the  face  of  the  cliff,  cutting  the 
amphibolite. 

■  16.  Still  farther  south,  on  the  east  slope  of  Peaked  Mountain,  west  of 
the  house  of  J.  Bliss,  jr.,  occurs  a  dike  of  about  equal  size  and  of  similar 
character.     These  dikes  in  Monson  were  already  traced  by  Percival. 

Trap  bowlders  are  very  abundant  along  the  western  slope  of  the  high 
ground  east  of  the  central  valley  of  Monson,  from  one  end  of  the  town  to 
the  other. 

17.  Another  plug  occurs  just  over  the  State  line  in  Stafford.  It  runs 
N.  10°  E.,  is  60  rods  long  and  200  feet  wide.  It  is  high  up  on  the  east 
slope  of  the  hill  which  lies  across  the  brook  west  of  where  the  Hampden- 
Stafford  road  crosses  the  State  line.  The  shdes  show  a  trace  of  decompo- 
sition. The  feldspars  of  first  generation  have  broad  bands  with  wavy 
extinction  from  strain;  the  second  are  very  complex  twins. 

18.  A  mile  S.  10°  W.  of  this,  where  the  road  from  the  State-line  Pond 
to  Somers  rises  to  the  top  of  a  high  hill,  another  dike  is  exposed  just  south 
of  the  road.  The  contact,  in  granite,  is  exposed  on  the  west.  The  strike 
is  N.  40°  E.  It  is  56  feet  wide,  200  feet  long,  has  steep  slope  on  the  north 
and  a  swamp  on  the  south.  The  sections  show  unusually  fresh  and  sharply 
and  regularly  outlined  plagioclase  of  only  one  generation. 

19.  A  third  stock  of  trap  occurs  a  half  mile  S.  10°  W.  of  this,  which 
crosses  the  next  east-west  road.  It  is  45  rods  long  from  north  to  south,  25 
rods  from  east  to  west.  The  gneiss  is  continuously  exposed  around  its  east, 
north,  and  west  sides.  It  is  a  compact,  light-gray  trap.  In  these  sections 
the  large  plagioclase  crystals  of  first  consolidation  have  the  central  portion 
out  nearly  to  the  border  changed  into  a  cottony  mass  of  plumose,  micalike, 
elongate,  ragged  scales,  while  the  clear  border  shows  at  one  end  a  marked 
wavy  extinction  and  the  other  end  extinguishes  sharply  at  25°  on  either 
side  of  the  twinning  suture.  This  is  an  unusual  change  to  some  micaceous 
or  zeolitic  mineral,  instead  of  to  kaolin. 


416  GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

20.  In  the  northeastern  corner  of  the  Palmer  quadrangle  a  dike  of  the 
same  fine-grained,  dark-gray  diabase  was  discovered  by  my  assistant,  Mr. 
C.  S.  Merrick.  It  is  nearly  a  mile  west  of  the  point  where  the  Boston  and 
Albany  Railroad  leaves  the  quadi-angle,  and  appears  in  the  crest  of  the  hill 
at  the  900-foot  contour.-*  It  is  about  100  feet  wide  and  strikes  N.  20°  E., 
and  is  plainly  a  part  of  the  dike  No.  10,  which  can  be  traced  north  across 
Ware  and  New  Braintree. 

A  MICROSCOPIC  DIABASE  DIKE  FROM  PELHAM,  AND  OLIVINE  AND   GLASS- 
BEARING  DIKES  FROM  MONSON. 

The  two  great  diabase  masses  of  the  Triassic  in  Massachusetts,  the 
Deerfield  and  the  Holyoke  dikes,  are  amygdaloidal  at  surface  and  aphanitic 
at  base,  but  everywhere  normally  crystalline,  and  everywhere,  even  when 
seeming  quite  fresh,  much  decomposed.  The  series  of  smaller  dikes  of  the 
same  rock,  when  run  in  the  gneiss,  parallel  to  and  a  few  miles  distant  from 
the  eastern  border  of  the  sandstone,  which  were  traced  across  Connecticut  and 
Massachusetts  by  Percival  and  Hitchcock,  are  in  texture  exactly  similar  to 
the  former,  showing  a  typical  diabase  texture,  but  always  very  much 
fresher.  They  often  send  off  a  great  number  of  apophyses,  which  sink  to 
very  small  dimensions  and  run  out  in  all  directions  and  to  considerable 
distances  through  the  gneiss,  which,  ordinarily  very  friable,  is  here  so 
indurated  that  thin  flakes  can  be  broken  off  and  slides  prepared  containing 
one  or  more  of  these  minute  dikes.  An  interesting  slide  of  this  character 
from  Pelham  contains  a  dike  0.9™™  wide  and  20™™  long.  It  is  a  tachylyte, 
shading  from  dark  gray  at  one  side  to  jet  black  at  the  other,  and  under  the 
microscope  is  a  colorless  glass  loaded  with  a  fine  dust,  apparently  magnetite. 
The  shading  into  black  is  due  to  the  occurrence  of  this  material  in  much 
greater  quantity  at  one  side  of  the  dike,  as  if  it  had  been  formed  horizontally 
and  the  magnetite  had  sunk  to  the  bottom.  The  rest  of  the  surface  has  a 
mottled  look,  like  a  miniature  representation  of  a  tiger's  skin.  This  comes 
from  the  fact  that  minute  angular  fragments  of  quartz  and  feldspar,  which 
are  scattered  through  the  mass,  are  surrounded  by  a  halo  of  the  same  black 
dust,  outside  which  a  broad  ring  of  the  glass  is  comparatively  clear.  This 
gives  the  whole  an  apparent  spherulitic  structure,  and  this  structure  is  really 
present  and  the  glass  is  in  a  state  of  tension  around  the  foreign  grains,  as 

'Percival,  Geol.  Conn.,  map. 


DIABASE  DIKES  AND  STOCKS  IN  THE  GNEISS.  417 

is  seen  bv  the  tact  that  the  clear  rings  j)ohirize  t'eebl)-  and  show  traces  of  a 
black  cross. 

On  the  upper  side,  i.  e.,  opposite  the  black  border,  tlie  lic^uid  rock 
forced  its  way  in  several  places  between  the  grains  of  the  bounding  rock. 
In  one  place  it  flowed  in  with  a  width  of  0.5™™,  showing  a  delicate  fluidal 
structure,  the  lines  of  black  dust  being  drawn  into  a  series  of  regular  par- 
abolas, exactly  as  in  a  diagi'am  of  the  surface  flow  of  a  river  around  a 
curve.  Another,  narrower,  runs  far  into  the  gneiss  and  passes  lengthwise 
of  a  large  biotite  crystal  in  a  gliding  plane,  with  a  width  of  0.02™™. 

The  contact  effects  of  the  small  dike  on  the  gneiss  are  also  interesting. 
Not  only  is  the  former  filled  with  minute  fragments  of  the  inclosing  rock, 
as  already  noted,  but  in  places  along  the  side  is  finely  crushed  and  dis- 
turbed, and  cemented  again  by  eruptive  material.  Crystals  of  triclinic 
feldspar  have  their  laminae  interrupted  and  echeloned  by  a  series  of  fine 
faults,  and  in  the  immediate  neighborhood  of  the  dikes  they  were  so  influ- 
enced by  heat  that  the  laminae,  instead  of  being  as  usual  (and  as  they  are 
here  farther  away)  perfectly  straight  and  sharply  defined  in  polarized  light, 
become  wavy  and  bend  over  into  the  direction  of  flow  of  the  lava,  and  the 
bands  of  color  pass  gradually  into  each  other. 

In  other  cases,  in  a  feldspar  apparently  fresh,  on  approaching  extinc- 
tion a  band  of  black  passes  in  from  the  border  to  the  center  and  disappears. 

The  large  biotite,  through  which  the  narrow  vein  passed,  seemed 
entirely  fresh,  but  in  polarized  light  it  was  seen  to  be  markedly  affected, 
apparently  by  compression,  so  that  it  broke  up  into  patches  of  color, 
arranged  along  the  sides  of  the  intruding  vein.  Smaller  crystals  of  biotite 
were  twisted,  so  as  to  show  a  brilliant  aggregate  polarization  in  long  inter- 
woven lines. 

The  large  quartz  grains,  usually  entirely  uniform,  were  broken  up 
into  irregular  patches  of  brilHant  color,  and  showed  marked  undulatory 
extinction. 

Specially  fine  cabinet  specimens  of  the  small  dikes  mentioned  above 
can  be  at  times  obtained  from  the  Monson  quarry — hand  specimens  of  the 
light-gray  gneiss,  with  three  or  four  dikes  narrower  than  one's  finger  cross- 
ing them,  and  at  times  bending  round  so  sharply  as  to  inclose  a  thin  wedge 
of  the  gneiss,  thinner  even  than  the  small  dikes  themselves. 

From  the  aphanitic  border  of  the  largest  dike  there,  which  is  only 
MON  XXIX 27 


418       GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

about  a  foot  wide,  I  cat  sections  which  showed,  under  the  microscope, 
many  porphyritic  ohvine  crystals  sharply  outlined,  some  nearly  fresh,  but 
most  well  advanced  in  the  change  to  serpentine.  Some  were  penetrated  by 
thick  branching  lobes  of  a  brown  glass,  which  in  one  case  took  up  more 
than  half  the  surface  of  the  section  of  the  crystal  and  was  accompanied  by 
two  separate  globules  of  the  same  glass  with  motionless  bubbles.  This  is 
the  first  certain  occurrence  of  olivine  in  the  traps  of  the  Connecticut  Valley 
in  Massachusetts,  and  this,  with  that  mentioned  on  page  411,  the  first  occur- 
rences of  a  glassy  modification  of  the  rock.  The  position  of  the  olivines 
and  their  large  size  suggest  that  they  may  have  been  formed  at  great 
depths  and  floated  up  to  their  present  position. 

Another  of  the  minute  dikes,  2"°"  wide,  in  the  gneiss  from  Monson  was 
cut.  It  had  for  part  of  its  boundary  a  border  of  crushed  gneiss,  the  triclinic 
feldspar  showing  undulatory  extinction,  and  the  dike  sent  off  into  this  a 
veinlet  0.1"™  wide.  It  was  of  finely  granular,  devitrified  tachylyte,  with 
a  lighter  border  one-third  millimeter  wide.  The  feldspars  in  it  were  from 
one-third  to  one  thirty- eighth  millimeter  in  length.  The  well-shaped  oli- 
vines allowed  measurement  of  (021)  A  (021)  =  98°  (calculated  99°  06'). 

THE   BEDDED   OR  CONTEMPORANEOUS  ERUPTIVES. 

THE    DEERFIELD    SHEET. 

This,  the  most  northern  occurrence  of  eruptive  rock  in  the  Trias, 
begins  near  the  northeastern  border  of  the  latter,  back  of  C.  M.  Conant's 
house,  in  the  west  edge  of  the  village  of  Grill,  and  extends  west  by  south 
past  the  house  of  J.  Blake,  where  it  is  slightly  faulted  and  where  it  has 
a  thickness  of  about  40  feet,  which  it  maintains  for  a  long  distance.  It  is 
compact  at  base  and  slightly  porous  at  surface,  and  has  low  southeast  dip 
with  the  conglomerate  in  which  it  is  intercalated.  At  its  crossing  of  the 
Gill-Tumers  Falls  road  it  is  again  slightly  faulted,  and  the  bed  was  traced 
only  to  this  fault  in  my  previous  study  of  it.^  It  turns  here  and  runs  down 
to  the  mouth  of  Fall  River,  where  it  is  again  faulted.  It  is  moved  about 
165  feet  to  the  west  and  an  opening  made,  through  which  the  Fall  River 
reaches  the  Connecticut.     From  this  point  it  runs  down  the  west  side  of 


1  The  Deerfield  dike  and  its  minerals:  Am.  Jour.  Sci.,  3d  series,  Vol.  XXIV,  1882,  p.  195. 


THE  DEEIIFIELD  SHEET.  419 

the  Coniiocticut,  tlirouy-h  Greeiilield  and  Deei-field,  and,  turning-  eastward, 
crosses  tlic  river  and  ends  in  Mount  Tob}^  It  is  at  first  included  in  the 
Long-niea(h)w  sandstones,  and  continues  south  in  them  until,  at  its  south 
eud,  it  runs  otl'  into  the  conglomerate  of  Mount  Toby. 

It  has  thus  the  characteristic  elongated  U  shape  which  appears  on  a 
scale  so  much  larger  in  the  Holyoke  range.  It  is  worthy  of  note  that  the 
high  western  border  of  the  valley,  which  I  shall  elsewhere  try  to  prove  to 
have  been  caused  by  faulting,  corresponds  in  direction  with  both  these 
sheets,  being  set  back  in  Greenfield  and  Northampton  so  as  in  each  case  to 
present  a  reentrant  angle  to  the  northwest  corner  of  the  trap  ranges,  with 
sides  parallel  to  the  corresponding  portions  of  the  ranges. 

The 'bed  is  about  21  miles  long,  and  where  the  Deei-field  River  breaks 
through  it  it  is  about  100  feet  thick;  at  Fall  River,  165  feet.  Where  it  is 
cut  by  the  artesian  well  of  the  Montague  Paper  Company  (see  p.  380)  it 
was  penetrated  110  feet,  which,  with  the  dip  of  40°,  would  give  a  thick- 
ness of  84  feet. 


THE  ALTERATION  OF  THE    DIABASE    BY    HEATED    WATERS  TO    A  PITCHSTONE- 
BRECCIA   AND    A   DIOPSIDE^PLAGIOCLASE    ROCK. 

Going  southward  from  the  bridge  over  Fall  River,  one  finds  in  the 
I'oadside,  just  before  coming  to  the  mouth  of  the  stream,  a  contact  of  the 
diabase  upon  the  sandstone  below — a  granitic  sandstone,  coarse  to  medium 
in  grain,  which  is  baked  for  an  inch  into  a  black  horustone  and  changed 
for  a  foot  into  a  strong  quartzite.     The  trap  above  is  little  aifected. 

Opposite  Mrs.  G,  P.  Heyward's,  in  Greenfield,  and  underneath  the 
lookout  tower  which  stands  on  the  crest  of  the  trap  ridge,  a  crushing  machine 
has  been  set  up  to  supply  the  city  with  road  material.  For  a  long  distance 
the  vertical  wall  has  been  cleared  and  a  most  interesting  contact  is  exposed. 
(See  PL  VIII.) 

Climbing  up  from  the  sand  flats,  over  60  feet  of  fucoidal  sandstones 
with  strike  N.  10°  E.  dip  40°  E.,  one  finds,  at  the  base  of  the  great  trap 
sheet  and  resting  on  the  sandstone  below,  a  layer  60  feet  thick,  made  up  of 
rounded  and  angular  blocks  of  trap,  of  all  sizes  up  to  3  feet  thick,  the  whole 
mass  penetrated  by  veins  of  fine  red  and  black  sandstone,  often  6  inches 


420  GEOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 

thick,  which  branch  upward  for  about  7  feet  from  the  main  mass  of  the 
sandstone  and  are  full  of  small  steam  holes  at  the  top. 

A  fine-grained  and  finely  porous,  reddish  trap  is  continued  downward 
from  the  compact  trap  above  in  all  the  interstices  between  the  blocks, 
cementing  them  together  in  the  same  way  that  the  sand  below  cements  the 
larger  blocks,  and  the  two  cements  meet  along  a  horizontal  line.  (See  PI. 
VIII.  The  person  seen  in  the  plate  stands  on  the  sandstone  and  touches 
this  line  with  his  finger.) 

As  the  great  mass  of  lava  flowed  over  the  bottom  of  the  bay,  its  con- 
gealed and  much  fissm-ed  crust  at  the  front  of  the  flow,  like  an  unrolling 
carpet,  gradually  passed  beneath  the  advancing  mass,  and  the  mud  rose  up 
into  all  the  fissures  in  the  crust,  while  the  heat  baked  it  into  a  porous  rock 
and  the  still  liquid  lava  within  oozed  into  the  cracks  above  to  meet  the  mud. 

The  above  partial  description  of  this  most  interesting  locality  was 
made  at  a  time  when  the  quarry  had  exposed  only  a  portion  of  the  surface 
to  study.^  A  more  careful  examination  of  the  place  brought  out  these 
facts:  The  basal  portion  of  the  bed  is  made  up  of  angular  blocks  of  trap, 
and  these  blocks  are  often  interlocked  and  a  common  structure  passes  from 
block  to  block,  showing  that  it  is  the  portion  of  a  bed  of  trap  in  place  and 
not  a  tuff  or  agglomerate  of  transported  blocks.  The  blocks  are  of  the 
common,  rather  coarse-grained  trap  of  the  sheet,  but  are  distantly  and 
coarsely  vesicular,  some  of  the  spherical  cavities  being  an  inch  across;  and 
what  is  most  striking,  many  of  the  blocks  have  rows  of  these  cavities  around 
their  borders  in  whole  or  in  part,  and  these  cavities  are  tubular  at  times  and 
closely  set  at  right  angles  to  the  fissure  which  separates  the  block  from  its 
neighbor.  At  times  two  adjacent  blocks  have  a  similar  arrangement  of 
tubular  cavities  on  either  side  of  the  crack.  The  arrangement  of  these  tubes 
at  the  surface  of  the  blocks  shows  that  the  slow  expansion  of  the  steam  was 
effective  after  the  mass  had  cracked  into  great  blocks.  Perhaps  the  increased 
heat  from  its  under-rolling  and  penetration  by  the  liquid  lava  may  have  been 
effective  here.  Moreover,  some  of  the  blocks  sm-rounded  by  the  finer  trap 
are  quite  spherical,  as  if  they  had  been  partly  remelted  after  being  envel- 
oped in  this  newer  trap.  Again,  it  is  a  very  partial  description  of  the  upper 
portion  of  the  wall  to  say  that  a  finer  trap  has  oozed  down  to  meet  the  iipcom- 
ing  red  sand  and  cemented  the  blocks  of  trap.     There  is  a  well-defined  line 

'  See  Am.  Jour.  Sci.,  3d  series,  Vol.  XLIII,  1892,  p.  146. 


THE  DEEKFIKLI)  SHEET.  421 

!il)(>ut  7  teot  above  the  saiulstoue  alon<^'  vvlucli  the  veins  of  red  sand  blend  with 
a  iinc'-<;'rainod,  reddish  material  quite  unlike  the  coarse  blocks  of  trap,  and 
this  reddish  material  cements  the  blocks  of  earlier  trap  together  for  a  few  feet 
hig-lier,  and  higher  up  the  blocks  grow  more  distant  and  smaller  and  disappear 
in  the  mass  of  the  newer  material,  which  is  cracked  into  small  fragments,  so 
that  the  whole  closely  resembles  a  tuff,  but  is  not  a  tuff,  if  the  idea  of  trans- 
portation of  fragmeutal  igneous  material  by  air  or  water  be  essential  to  the 
definition  of  a  tuff.  It  is  a  breccia  of  sand,  trap  fragments,  and  glass,  pro- 
duced by  explosions  of  the  water  introduced  with  the  mud.  In  places  it 
loses  the  red  color  and  becomes  greenish.  On  examining  the  whole  face  of 
the  cliff,  it  is  seen  that  this  tuff-like  condition  continues  up  half  the  height  of 
the  bed,  and  its  upper  boundary  continues  north  and  south  for  a  long  dis- 
tance.    This  is  visible  in  the  plate. 

A  careful  examination  of  the  zone  of  contact  of  the  sandstone  veins 
and  the  newer  trap  shows  the  latter  to  be  compact  or  finely  porous,  as 
contrasted  with  the  blocks  of  trap,  which  are  very  coarse  amygdaloidal. 

The  newer  trap  or  glass-breccia  is  reddish,  because  it  is  an  intimate 
mixture  of  trap  and  red  sand,  and  for  20  feet  up,  as  far  as  one  can  climb 
at  the  quarry,  the  mixture  of  the  filaments  of  sand  and  trap  are  most  inti- 
mate, and  on  a  polished  surface  it  is  seen  that  the  delicate  anastomosing 
films  of  the  trap  penetrating  the  sand  could  have  reached  their  present  posi- 
tion and  condition  only  in  a  liquid  state,  while  the  thin  layers  of  sand  are 
as  intimately  mixed  in  the  trap. 

Under  the  microscope  (see  fig.  24,  A,  B,  p.  422)  the  thicker  portions  of 
the  sand  filaments  (left  side  of  figures)  in  specimens  taken  about  20  feet 
from  the  base  of  the  sheet  are  of  the  same  texture  exactly  as  in  the  broad 
intruded  masses  of  sandstone  below,  but  are  blackened  around  their  border 
by  the  caustic  action  of  the  adjacent  lava,  and  as  they  grow  thinner  they 
become  black  across  their  entire  width.  This  seems  to  be  caused  by  the 
coating  of  the  sand  grains  with  hematite  derived  from  the  iron  of  the  red 
mud  and  recrystallized  by  the  heated  waters.  These  borders  bristle  out- 
wardly also  with  beautiful  hexagonal  plates  of  blood-red  hematite,  and  the 
same  plates  are  found  also  in  the  sand  and  in  the  surrounding  rock. 

The  second  constituent  of  the  rock  is  the  trap,  here  in  somewhat 
abnormal  development.  It  is  in  small  fragments  and  minute  filaments, 
penetrating  the  sand  in  every  way.      It  contains  the  large,  angular,  and 


422 


GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 


well-formed  plagioclase  twins  of  earliest  consolidation,  which  are,  as  usual, 
dusted  with  impurities,  or  decomposition  products,  and  a  few  fine  rods  of 
later  growth,  and  these  constituents  are  entirely  like  those  found  in  the 
normal  trap.     They  are,  however,  not  accompanied  by  magnetite  and  augite, 


/ 


^    w 

^v^ 


FiQ.  21.— Thin  sections  of  aand  and  glass  breccia  ( JL,  B)  from  the  base  of  the  Greenfield  sheet  at  the  city  quarry  and  of 
trap  (O)  from  Cheapside.    Drawn  by  Charlotte  F.  Emerson.    ^1  X  30.    .B  X  85.    Ox  30. 

as  in  the  normal  trap,  but  are  included  in  an  olive-green  streaky  and  hardly 
differentiated  magma,  which  is  often  thrust  in  among  the  sand  grains  where 
the  feldspar  can  not  follow.  Large  trap  fragments  appear  at  the  right  of 
A  and  B. 

The  third  constituent  of  the  rock,  and  a  most  interesting  one,  is  of 
aqueous  or  igneo-aqueous  origin,  it  being  plainly  formed  by  the   action 


THE  DEERFIELD  SHEET,  423 

of  the  vviiters  of  the  mud  ou  the  heated  lava  under  ])ressure.  It  appears  as 
narrow  limpid  bands  in  A  and  B,  often  interjected  between  the  other  con- 
stituents. It  is  made  up  mostly  of  a  clear  feldspar,  in  blades  and  plates  sev- 
eral times  twinned,  of  very  fresh  appearance,  and  polarizing  in  bluish  whites, 
with  the  stron<^-,  wavy  or  central  extinction  which  characterizes  the  water- 
deposited  albites  of  the  cavities  of  the  red  diopside-diabase  of  the  dike  at 
Cheapside  (fig.  24,  C).  This  feldspar  is  also  closely  like  the  ordinary  pla- 
gioclase  of  the  amphibolites  and  albitic  schists  of  the  metamorphic  series 
farther  west.  There  is  also  a  pyroxenic  mineral  of  a  quite  peculiar  character 
associated  with  this  feldspar,  and  like  it  plainly  of  secondary  origin.  It  has 
extinction  a  =  emerald-green,  h  —  clove-brown  to  violet,  ,c  =  red-brown. 

In  this  rock  small  groups  of  stout,  colorless  diopside  crystals  occur, 
often  bristling  on  the  surface  of  the  sand  filaments  like  the  hematite  (which 
is  another  constituent  of  this  rock),  and  in  one  case  a  well-formed  arrow- 
headed  twin  of  this  mineral  was  observed.  The  considerable  development 
of  the  green  pyroxenic  mineral  gives  much  of  the  tuff-like  rock  a  green 
color  and  the  appearance  of  being  greatly  weathered  diabase,  and  this 
somewhat  abnormal  variety  forms  narrow  and  interrupted  bands  between 
the  filaments  of  the  red  mud  and  small  fragments  of  the  trap.  These  latter 
have  the  primary  and  secondary  feldspars  weathered  and  inclosed  in  an 
olive-green  groundmass.  The  hematite  plates  penetrate  to  the  very  center 
of  these  fragments. 

The  mild  was  thus  most  intimately  blended  with  the  liquid  trap  in 
which  the  lath-shaped  feldspars  had  already  been  crystallized.  It  furnished 
water  for  the  hydration  of  the  groundmass  into  an  olive-green  nonpolarizing 
glass,  and  some  of  the  same  superheated  water  produced  the  abnormal 
igneo-aqueous  deposit  which  unites  the  normal  trap  with  the  sand  filaments. 

Several  years  after  the  foregoing  description  was  written  I  made  a 
comparative  study  of  the  above  occurrence  and  similar  tuff-like  beds  in 
Meriden,  Connecticut,  during  which  many  slides  were  examined  and  an 
analysis  of  the  glass  at  Meriden  was  made.  This  gave  me  much  clearer 
ideas  of  the  part  taken  by  the  water  in  forming  and  shattering  the  glass 
(which  proves  to  be  a  basic  pitchstone)  to  make  the  fine  sand  and  trap- 
breccia  mentioned  above,  in  carrying  up  portions  of  the  basal  bed  to 
become  the  bomblike  masses,  and  in  promoting  the  formation  of  a  rock 
resembling  a  crystalline  schist.     I  therefore  reprint  here  the  substance  of 


424  GEOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 

this  article,  so  far  as  it  relates  to  the  Greenfield  bed,  at  the  expense  of  a 
little  repetition.^ 

The  flow  of  the  submarine  lava  bed  seems  here  to  have  been  unusually 
rapid,  and  the  under-rolling  to  have  been  a  somewhat  subordinate  phenom- 
enon; still,  the  convection  currents  rising-  from  the  front  of  the  bed  seem  to 
have  generally  chilled  it,  so  that  a  somewhat  thin  layer  of  compact,  heavy, 
fine-grained  trap  was  solidified  and  under-rolled  to  form  a  basal  bed  protect- 
ing the  liquid  mass  above.  When  the  sheet  had  advanced  over  the  muddy 
bottom  so  far  that  the  imprisoned  vapors  could  not  escape  laterally,  some 
slight  and  local  disturbance  broke  up  this  basal  layer  more  or  less,  the 
heat  reached  the  water-soaked  sand  below,  and  steam  and  mud  frothed 
up  into  the  mass  of  the  still  liquid  lava  in  great  quantity,  carrying  many 
blocks  of  the  basal  bed.  These  abnormal  conditions  promoted  the  forma- 
tion of  unusual  varieties  of  trap.  The  absorption  of  water  caused  the 
formation  of  much  basic  pitchstone,  while  repeated  smothered  explosions 
shattered  and  commingled  the  heterogeneous  products. 

GENERAL  CHARACTER. 

For  a  thickness  of  30  to  70  feet  and  for  a  distance  of  several  miles  in 
the  vicinity  of  Grreenfield  the  basal  portion  of  the  trajD  sheet  is  a  mixture 
of  sand,  fragments  of  various  sandstones,  fragments  of  various  kinds  of 
diabase — some  with  glass  base,  some  with  hyalopilitic  base,  and  some 
resembling  andesites,  all  unlike  the  monotonous  Triassic  diabase — and 
abundant  fragments  of  glass,  all  cemented  by  glass,  and  variously 
shattered  and  recemented,  and  the  interstices  filled  by  a  water-deposited 
mixture  of  albite,  diopside,  calcite,  segirine-augite,  and  hematite. 

The  main  mass  of  the  trap  sheet  is  normal  and  continuous  above  this 
confused  mass,  and  in  many  places  the  basal  portion  of  the  sheet  can  be  seen 
to  be  a.  continuous  mass  of  trap  beneath  the  breccia,  so  that  the  latter  must 
have  been  formed  in  the  midst  of  the  sheet  itself  The  sheet  is  a  normal, 
contemporaneous  sheet,  often  showing-  a  ropy  flow  structui'e  at  the  surface. 

GREENFIELD    QDAERY  EXPOSURES  AND   CONTACTS. 

For  a  mile  north  of  the  quax'ry  beneath  the  observation  tower  east 
of  Greenfield  one  can  walk  along  the  line  of  contact  of  the  trap  on  the 

'  Bull.  Geol.  Soc.  America,  Vol.  VIII,  p.  64. 


s   » 


H    g   s 


<  s 


^ 


PLATE  Villa. 


425 


PLATE   Villa. 

DETAILS  OF  TRAP  RIDGE  EAST  OF  GREENFIELD. 

Fig.  1. — Photograph  of  the  south  face  of  a  large  bowlder  at  the  foot  of  the  cliif  below  the  quarry. 
The  rounded  and  angular  blocks  are  trap,  and  they  are  inclosed  in  the  sand  and  glass 
mixture,  which  often  shows  fluidal  structure.  Commencing  to  the  right  of  the  watch 
chain,  which  is  to  be  seen  in  the  lower  left-hand  corner  of  the  picture,  and  continuing 
upward  for  twice  the  length  of  the  chain  is  a  series  of  four  rounded  blocks  connected  by 
narrow  necks,  and  sending  out  narrow,  angular  lobes — forms  which  can  not  have  resulted 
from  explosions  throwing  masses  of  lava  into  the  air.  The  effect  of  the  pile  of  great 
round  blocks  with  comparatively  small  amount  of  interstitial  matter  can  only  partly  be 
given  by  the  photograph.     See  page  431. 

Fig.  2. — Enlargement  of  the  part  of  fig.  1  which  lies  to  the  right  of  the  watch  in  the  photograph. 
A  band  of  the  sand  and  glass  mixture  extends  across  from  the  upper  right  corner  and 
separates  a  large,  rounded  block  above  from  a  double  block  below,  whose  parts  are 
joined  by  a  narrow  neck  near  the  center,  while  the  part  to  the  right  sends  down  a  long, 
curved  lobe  into  the  breccia  below.  This  shows  one  of  the  forms  which  can  not  have 
been  "bombs"  in  the  ordinary  sense.     See  page  431. 

426 


PLATE  VIIIj. 


427 


PLATP]   VI 1 1ft. 

INCLUSION  OF  MUD  IN  UPPER  SURFACE  OF  TRAP  SHEET. 

Fig.  1.— a  block  of  trap  from  the  contact  of  a  sheet  of  sandstone  12  feet  long  and  a  foot  wide  which 
was  included  in  the  trap  a  few  feet  below  and  parallel  with  the  surface.  The  lower  surface 
of  the  specimen  was  in  contact  with  the  sandstone.  The  whitest  spots  are  steam  holes 
filled  by  secondary  calcite.  Vhe  trap  is  full  of  drops  and  lobate  masses  of  the  gray  mud. 
From  the  north  end  of  the  east  wall  of  the  cut.  Dibbles  Crossing,  Holyoke.  About  two- 
thirds  natural  size.     From  photograph.     See  page  456. 

Fig.  2. — Polished  surfaces  of  pieces  from  the  south  end  of  the  cut,  to  show  the  intimate  mixture  of  the 
shattered  trap  and  the  light-gray  mud.  The  mud  fills  many  of  the  steam  holes  in  whole 
or  part.     Natural  size.     From  photograph.     See  page  456. 

428 


U.   ti.  QEOLOOICAL  SURVEY 


MONOQHAPH  XXIX       PL.    Vlll/; 


INCLUSION  OF   MUD  IN   UPPER  SURFACE   OF  TRAP  SHEET. 


PLATE  VIIIc. 


429 


PLATE    VI  lie. 

THIN  SECTIONS  OF  MATERIAL  FROM  GREENFIELD  AND  MERIDEN  "ASH  BED." 

Fig.  1. — Red  htmatitic  trap  with  secondary  albite  in  perfect  twinned  crystals  lining  the  interior  of 
steam  holes.  Two  large  half-filled  cavities  and  three  smaller  ones,  wholly  filled,  appear. 
The  large  porphyritic  plagioclase  to  the  right  is  mottled  from  decomposition.  Green- 
field, near  Cheapside  Village,  at  the  electric  railroad  cut.  See  page  442.  Magnified  20 
times;  crossed  nicols. 

Fig.  2. — The  interstitial  aqueous  deposit  of  plagioclase  (probably  albite),  diopside,  and  segerine- 
augite.  The  plagioclase  has  a  dusty,  altered  center,  caused  by  an  early  change  to  calcite 
and  a  limpid  exterior  of  later  formation,  which  resembles  the  secondary  plagioclase 
of  fig.  1.  The  diopside  is  marked  by  strong  boundaries  and  distant  cleavage.  The 
segerine-augite  is  in  dark  patches.  The  darker  bordering  portions  are  altered  to  serpen- 
tine with  development  of  cleavage.  At  the  lower  border  patches  of  the  black  sand  appear. 
At  the  top  and  right  edge  are  isolated  spberulites.  Greenfield  quarry,  20- feet  above  base 
of  bed.     See  page  434.     Magnified  35  times ;  crossed  nicols. 

Fig.  3. — Scoriaceous  sandstone.  The  dark  parts  are  the  rusty  sandstone,  red  in  the  interior  of  the 
bands,  and  blackened  by  heat  exteriorly.  They  show  mud  flow.  The  light  parts  are 
irregular,  limpid,  plagioclase  grains.  The  mud  has  shrunk  away  at  the  top  from  a  first 
growth  of  this  kind,  leaving  a  thin  film  of  black  grains,  and  in  the  narrow  space  a  more 
limpid,  plagioclase  growth  occurs.  In  the  center  of  the  older  growth  is  a  highly  refring- 
ent  mineral  (datolite?),  showing  a  micropegmiititic  structure  with  the  plagioclase.  See 
page  435.     Greenfield,  Cheapside  cut.     Magnified  20  times. 

Fig.  4. — Greenish-brown  glass  with  yellow  borders,  which  are  devitrified  in  series  of  small  spherulites 
with  dark  centers.  The  glass  has  been  shattered,  while  the  fragments  were  slightly 
plastic.  The  fragments  are  in  place  in  the  slide,  and  the  cavities  are  partly  filled  by  a 
secondary  water-deposited  albite  growth.  See  page  432.  From  Meriden  "ash  bed,"  near 
top  on  south  path.     Magnified  35  times. 

Fig.  5. — Hyalopilitic  diabase  from  the  Meriden  "ash  bed."  Base  formed  of  tufted,  feathery,  and 
fasciculate  groups  of  beaded  threads.  Large  olivine  at  right,  large  augite  full  of  glass 
inclusions  on  left.  Contact  of  basal  bed  on  glass  breccia.  See  page  436.  Magnified  35 
times. 

430 


U.   b.   CiEOLOtilCAL  SURVEY 


MONOGRAPH  XXIX      PL.   VIIIC 


4  5 

THIN  SECTIONS  OF   MATERIAL  FROM  GREENFIELD  AND  MERIDEN   "ASH   BED.' 


TUB  DEEKFIELD  SHEET.  431 

sandstone  with  the  vertical  wall  of  the  traj)  risinj>-  above.  Here  there 
seems  to  ha\e  been  no  distinet  basal  bed,  but  the  \\hole  mass  was  cooled 
nearly  to  the  crystallizing  point  when  the  sand  rose  up  into  it  at  almost 
equal  intervals,  and  the  streams  of  the  sand  and  glass  breccia  formed  by 
the  water  rise  in  g-reat  streaks  or  "schlieren,"  anastomose,  and  pass  with 
iiuidal  structure  around  the  great  rounded  blocks  of  the  normal  traj),  which 
make  somewhat  more  than  half  the  wall. 

At  the  quarr}^  is  a  more  distinct  basal  bed  of  trap  7  or  8  feet  thick, 
more  or  less  shattered  and  displaced,  and  the  sand  can  be  seen  continuous 
with  the  underlying  sandstones  rising  in  rifts  in  this  basal  bed  and  frothing 
out  into  a  scoriaceous  sandstone,  where  it  meets  and  blends  with  the  breccia 
above.  This  breccia  is  60  feet  thick — a  greenish  mass  of  shattered  glass  and 
trap,  full  of  filaments  of  red  sand  shining  with  hematite  scales. 

The  rounded,  bomblike  masses  of  the  compact  and  crystalline  trap 
which  are  contained  in  this  breccia  grade  superficially  through  hyalopilitic 
trap  into  the  green  glass,  and  while  compact  at  center  are  toward  the  sur- 
face full  of  radiating  steam  pores.  They  seem  to  have  been  often  carried 
aloft  by  the  explosions  into  the  still  liquid  glass,  partially  melted,  and  made 
siiperficially  plastic  by  reheating,  so  that  the  steam  has  been  able  to  struggle 
to  the  surface  from  the  outer  portion.  Where  they  are  large  and  angular 
they  have  been  cari'ied  but  a  little  way  from  the  base  where  they  were 
formed;  where  they  are  small  and  spherical  they  are  far-carried  and  much 
resorbed  in  the  glass  mass. 

Among  these  blocks  are  many  long  sheets  and  rounded  masses  con- 
nected by  narrow  necks,  which  could  not  have  been  blown  into  the  air  and 
have  fallen  as  common  bombs.     (See  PL  Villa,  p.  426.) 

A  little  way  north  of  the  quarry  one  can  climb  up  the  whole  face  of 
the  trap  by  a  steep  path,  and  60  feet  from  the  base  can  study  the  top  of 
the  breccia.  Here  are  unusually  large  masses  of  sand  frothed  up  into  an 
amygdaloidal  sandstone  and  filled  with  water-deposited  silicates  like  the 
Cheapside  rock  (see  PL  VIII  c,  fig.  3),  and  above  this  the  trap  is  normal  and 
crystalline  and  full  of  steam  holes  for  a  few  feet,  and  then  grades  into  the 
common  compact  columnar  trap  of  the  upper  part  of  the  sheet.^ 

'  In  reporting  my  brief  account  of  this  case,  Professor  Dana  has  destroyed  the  meaning  of  the  whole 
by  an  error.  He  says  that  the  trap  sheet  rests  on  coarse  sandstone-breccia  12  to  16  feet  thick,  instead 
of  coarse  trap-breccia.     (Manual  of  Geology,  1895,  footnote  on  p.  805.) 


432  GEOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 


PETEOGRAPHICAL  DESCRIPTION. 

DIABASE-PITCHSTONE. 


The  diabase-pitclistone  iii  its  purest  form  is  a  dark  liver-brown  pitch- 
stone,  dull-green  or  mottled  brown  and  green  by  reflected  light,  and  red- 
brown  by  transmitted  light.  It  is  often  an  apple-green  glass  with  the  same 
dichroism.  It  has  resinous  pitchstone  luster,  and  so  differs  from  most  tachy- 
lytes.  The  microscope  shows  a  very  minute,  regular  network  of  cracks, 
often  developing  into  a  perlitic  structm-e  around  crystals  and  spherulites, 
which  explains  this  luster.  The  deep-brown  glass  streaked  with  very  deep 
brown  is  wholly  amorphous  and  hardly  to  be  distinguished  from  the  Kilauea 
glass  in  common  light,  and,  like  it,  it  is  not  affected  by  acid.  The  pheno- 
crysts  are  of  similar  size  and  distribution,  but  with  polarized  light  the  feld- 
spar rods  are  always,  and  the  large  colorless  pyroxenes  sometimes,  changed 
to  granular  calcite,  easily  removed  by  acid;  the  olivines,  to  fibrous  serpentine. 

The  fresh  glass  is  full  of  small  grains  (cumulites),  white  by  reflected 
light,  red-brown  by  transmitted  light,  which  are  made  of  aggregates  of 
minute  grains  (globulites).  Even  where  the  glass  seems  compact  it  often 
separates  into  small  sheets  and  portions,  showing  minute  curdled  surfaces, 
and  under  the  microscope  the  same  wrinkled  surfaces  can  be  seen  where 
small  cavities  have  collapsed  or  where  the  fragments  have  flowed  or  have 
been  drawn  out  in  threads. 

The  glass  has  been  shattered  into  angular  fragments  by  sudden  explo- 
sion while  still  able  to  flow  under  slow  pressure.  Each  of  the  fragments 
is  then  bordered  by  a  layer  of  even  thickness  of  paler-brown  and  equally 
nonpolarizing  glass — an  effect  of  the  heated  waters  on  the  iron  content. 

The  larger  fibrous  spherulites  in  the  glass  are  usually  perfect  circles 
or  ovals,  but  they  are  sometimes  distorted  by  flow  or  pressure.  They  are 
often  bordered  by  several  concentric  bands  of  lighter  and  darker  brownish- 
green  glass,  each  band  having  a  concentric  radiate  structure.  The  central 
part  is  colorless  and  beautifully  radiate-fibrous,  showing  perfect  black  cross. 
The  fibers  are  optically  positive  and  polarize  like  a  plagioclase.  They  are 
not  affected  by  boiling  acid  or  alkali.  Sometimes  the  centers  are  filled  by 
a  greenish  granular  mass,  which  scarcely  polarizes,  showing  only  scattered 
light  points.  The  spherulites  are  often  broken  and  found  in  parts  in  the 
breccia,  and  the  layers  separated  and  crushed,  so  that  the  glass  seems  full  of 
fragments  of  eggshells. 


THE  DEERFIELD  SHEET.  433 

A  fibrous  devitrification  sometimes  afi'ects  all  the  fragments  of  a  slide, 
each  oue  beinc  now  a  pale-yellow  devitrified  glass  of  a  finely  tufted  or 
fibrous  sti-ueture  radiating-  from  many  centers.  The  fibers  have  the  same 
optical  properties  as  do  the  spherulites.  The  inclosing  glass  is  more  granu- 
larly  devitrified,  polarizing  in  dots. 

The  o-lass  sometimes  rindergoes  a  peculiar  calcification,  which  seems  to 
me  rather  a  metamorphic  change  produced  by  the  heated  waters  than  a  later 
decomposition  by  cold  atmospheric  waters.  A  fragment  of  glass  will  be  red- 
brown  at  the  center,  pale-brown  farther  out,  and  perhaps  colorless  at  its 
border;  its  angular  boundaries  will  be  sharply  defined  and  the  phenocrysts 
equably  disseminated  through  the  whole,  and  with  common  light  the  whole 
seems  unchanged  glass.  It  will,  however,  polarize  in  whole  or  part  in 
broad  patches  of  bright  and  softly  blended  colors  and  show  everywhere 
the  luiiaxial  figure  of  calcite.  Acid  removes  it  readily  and  leaves  only  a 
powdery  remnant.  The  outer  colorless  part  is  generally  devitrified  in 
plumose  patches  or  in  series  of  minute  fibrous  globes  in  the  greenish  fibrous 
devitrified  glass.  The  calcite  disappears  rapidly  with  acid,  leaving  an 
opaque-white  granular  residue,  while  the  colorless  glass  becomes  opaque- 
white  in  lines  and  streaks,  showing  a  concealed  fiuidal  structm-e. 

It  is  noteworthy  that  among  all  the  reactions  carried  out  here  so  little 
quartz  is  set  free.  Under  the  influence  of  the  heated  and  carbonated  water 
the  glass,  rich  in  calcium  and  alkalies  and  poor  in  silica,  tends  to  split  into 
calcite  and  acid  feldspars.  This  explains  the  formation  of  spherulites  and 
the  fibrous  devitrification  of  the  glass,  with  the  abundant  development 
of  calcite. 

QLASS-BBECCIi.. 

Under  the  microscope  a  fragment  of  the  greenish  tuff-like  mass,  taken 
20  feet  from  the  base  of  the  bed,  was  composed  as  follows: 

The  first  thing  that  attracted  attention  was  the  fine  red  sand,  each 
gi-ain  being  covered  with  iron  rust.  Where  this  was  in  thick  masses  it  was 
still  red  in  the  interior,  but  on  the  exterior  was  black  from  the  recrystalliza- 
tion  of  the  iron  rust  by  the  caustic  effect  of  the  melted  lava,  in  which  it  had 
been  disseminated  in  threads  and  sheets.  In  the  interstices  between  these 
dark  sand  portions  many  minute  angular  grains  of  diabase,  like  that  found 
in  the  basal  bed,  were  scattered.  These  had  been  broken  up  by  an  early 
explosion  and  earned  up  from  the  base  with  the  sand.     The  whole  had  been 

MON  XXIX 28 


434       GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

cemented  by  an  olive-green  glass,  containing  a  few  crystals  of  plagioclase 
and  scattered  spherulites,  penetrating  among  the  sand  grains  and  to  the 
very  center  of  sand  areas,  which  would  otherwise  have  been  called  sand- 
stone fragments.  The  whole  thus  formed  has  been  again  shattered,  and  is 
now  cemented  by  a  hot-water  deposit  of  albite,  calcite,  diopside,  and 
gegirine-augite.  Beautiful  large  hexagonal  plates  of  hematite  bristle  over 
the  trails  of  sand  grains,  and  in  all  the  other  constituents  except  the  basal 
trap  fragments.  Sometimes  cavities  of  later  formation  are  filled  by  radiat- 
ing chalcedonic  growths,  with  centers  of  calcite  and  ankerite  and  copper 
pyrite. 

The  water-deposited  plagioclase  (PI.  VIII  c,  fig.  2,  p.  430,  the  colorless 
center)  has  the  appearance  and  the  optical  character  of  the  small  but  per- 
fect albites  (PI.  VIIIc,  fig.  1,  and  fig.  24,  C,  p.  422)  which  line  the  steam 
holes  in  many  places  in  this  bed,  and  often  rest  upon  the  earlier  diabantite. 
These  I  have  proved  by  optical  and  specific-gravity  tests  to  be  albite.^ 
It  has  also  a  curious  resemblance  to  the  albite  of  the  "albitic"  schists  and 
amphibolites,  and  the  whole  mixture  has  some  resemblance  to  a  crystalline 
schist. 

The  gegirite-like  mineral  (PI.  VIIIc,  fig.  2,  the  dark  grains)  is  in 
shapeless  grains  and  shows  a  strong  prismatic  cleavage  like  that  of  augite. 
It  is  intergrown  with  the  feldspar,  calcite,  and  diopside  in  such  a  way  as  to 
show  that  they  were  all  deposited  together.  The  absorption  in  this  min- 
eral is  very  strong:  a  =  deep  blue-green,  Ii  :=  violet  to  olive-brown,  some- 
times with  shade  of  green,  c  =  brownish  yellow.  A  single  twin  with  an 
extinction  of  38°  on  either  side  of  the  suture  was  found,  and  the  maximum 
of  the  blue-green  absorption  was  also  at  38°  on  either  side  of  the  suture, 
and  this  blue  absorption  represented  the  greatest  elasticity.  The  mineral 
has  thus  the  negative^  sign  and  the  strong  absorption  of  segirite  and  the 
optical  figure  in  the  position  of  augite.  It  is  therefore  allied  to  the  segirine- 
augite  of  Rosenbusch,  but  the  absorption  parallel  to  a  is  clear  blue-green 
and  not  grass-green.  Large  patches  of  the  mineral  are  changed  to  a  yellow- 
green  serpentinous  mineral,  which  under  crossed  nicols  is  almost  black,  but 
with  scattered  points  of  light. 

iMineralogical  Lexicon,  under  "Albite":  Bull.  U.  S.  Geol.  Survey  No.  126,  1895. 

2  By  an.  oversiglit  the  mineral  is  said  to  have  the  positive  sign  in  the  article  cited,  and  the  absorp- 
tion color  is  given  as  blue.  This  is  only  true  in  some  sections  between  a  and  b,  which  blend  the  blue, 
"reen,  and  violet. 


THE  DEEliFIELD  SHEET.  435 

The  (liopside  is  iu  stout,  small  crystals  or  in  long,  stout  prisms,  some- 
times In-oken.  They  are  enveloped  by  the  segirine-augite  without  common 
orientation. 

AUYQDALOIDAL  SANDSTONE. 

One  of  the  columns  of  sand  rising  from  the  sandstone  and  penetrating 
the  basal  bed  at  the  Greenfield  quany  expands  9  feet  from  the  base,  where 
it  passes  above  the  basal  bed  into  the  glass-breccia,  and  its  central  portion 
presents  a  scoriaceous  appearance.  It  is  a  red  sandstone  filled  with  more  or 
less  rounded  spots  of  a  white  silicate,  which  I  have  no  doubt,  from  my 
examination  of  other  similar  cases,  is  mainly  a  granular  plagioclase.  The 
same  thing  is  developed  much  more  extensively  at  the  top  of  the  breccia, 
on  the  path  going  up  over  the  cliff  north  of  the  quarry.  Here  for  several 
feet  in  thickness  the  rock  is  a  red  sandstone  closely  filled  with  small  cavi- 
ties. The  whole  makes  the  impression  of  a  rather  coarse,  red  amygdaloid 
with  white  amygdules. 

A  still  more  attractive  form  of  the  same  rock  is  found  in  the  cut  of 
the  electric  road  at  the  Deerfield  River,  a  mile  south  of  Cheapside  (see 
PI.  VIIIc,  fig.  3).  Here  a  light-red  sand  rock  is  filled  with  the  fresh  white 
amygdules.  Under  the  microscope  the  sandstone  between  the  white  fillings 
has  a  beautiful  fluidal  structure,  thus  heightening  the  resemblance  to  an 
amygdaloid.  The  cavities  are  superficially  blackened  by  the  recrystalliza- 
tion  of  the  iron  oxide.  The  white  filling  is  mainly  a  fresh  matted  network 
of  plagioclase  blades,  which  shows  distinct  triclinic  striation  rather  more 
frequently  than  is  iisual  in  this  water-deposited  feldspar.  They  are  ragged- 
edged  from  interference  due  to  rapid  crystallization.  In  the  center  of  the 
cavities  is  another  mineral  into  which  the  feldspars  penetrate  with  a  micro- 
pegmatitic  structure  or  which  runs  out  among  them.  It  polarizes  with 
bright  yellows,  and  I  suspect  it  to  be  datolite,  as  a  mineral  with  the  high 
glassy  luster  of  datolite  can  be  seen  with  the  lens  in  the  centers  of  some 
cavities.  It  shows  no  cleavage,  and  it  has  a  rough  surface  like  olivine, 
which  agrees  with  the  high  refractive  index  of  datolite.  Other  slides  of 
this  occurrence  showed  a  curious  radiate-fibrous  structure  with  coarsely 
beaded  fibers  and  extinction  up  to  40°,  and  some  smaller  stout,  square 
prisms  with  flat  ends.  They  present  all  the  peculiarities  of  wollastonite. 
Another  peculiarity  is  that  the  cavities  seem  to  have  been  filled  with  the 
mixture  described  above,  after  which  the  sand  has  shrunk  away  from  the 


-436       GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

filling  for  a  considerable  distance  along  one  or  more  sides,  leaving  a  film 
of  the  black  sand  grains  attached,  and  then  a  more  limpid  feldspai-  has 
grown  in  the  narrow  cavities  thus  formed. 

CONTACT  MATERIAL. 

A  slide  cut  within  the  porous  outer  portion  of  the  trap  from  the 
contact  of  one  of  the  bomblike  masses  of  trap  with  the  glass-breccia 
showed  only  a  very  feldspathic  and  vesicular  diabase.  Specimens  cut 
from  the  fused  border  between  the  two  showed  a  rock  with  the  aspect  of 
an  augite-andesite.  The  well-shaped  feldspars  of  two  generations  and  the 
equally  well-shaped  olivines  were  inclosed  in  an  opaque  red-brown  base, 
which  in  thinnest  places  revealed  its  hyalopilitic  or  fibrous  structure. 
(PL  VIIIc,  fig.  5,  p.  430.)  Its  outer  surface  had  at  times  a  rounded  and 
lobed,  fused  sm-face,  and  just  under  the  surface  a  single  row  of  steam  holes 
filled  with  silica,  all  indicating  a  superficial  remelting. 


LITHOPHTS^, 


In  one  large  specimen  from  near  the  base  of  the  bed  north  of  the 
quarry  at  Greenfield  the  breccia  was  full  of  well-formed  lithophysse  a  half 
inch  to  an  inch  and  a  half  in  diameter.  The  cavities  were  half  filled  with 
cm-died  masses  of  a  lighter  rock. 

CHEMICAL  DISCUSSION. 

In  his  article  on  the  lavas  of  the  Sandwich  Islands  and  other  volcanic 
islands  of  the  Pacific,^  Cohen  states  that  all  the  basic  glass  found  was 
anhydrous,  and  in  general  a  basaltic  pitchstone  has  not  been  described. 

I  have  studied  slides  of  many  tachylytes,  and  only  that  of  Ostheim, 
in  Hessen,  with  its  green  superficial  color  and  liver-brown  interior  color, 
resembles  these  glasses.  I  have  not  seen  any  analysis  of  this  rock  giving 
water  determination.  It  is  deeper  brown  than  most  of  the  glass  here 
studied,  and  contains  large,  round,  oval  spherulites  with  still  deeper  color, 
with  radiate  structure,  and  drusy  surface.  The  other  basaltic  obsidians 
quoted  by  Zirkel  do  not  contain  more  than  2.75  per  cent  of  water. 

The  following  analysis  of  basic  pitchstone  from  the  Meriden  "ash 
bed,"  by  Mr.  H.  N.  Stokes,  of  the  United  States  Geological  Survey,  was 
made   on   a   pure   liver-brown  glass   identical  with  that  here  described. 

^Neues  Jahrbuch  fiir  Mineralogie,  Vol.  LVIII,  p.  57. 


THE  DEER  FIELD  SHEET. 


437 


It  has  specific  gravity  of  2.87,  aud  melts  easily  to  a  black  magnetic  and 

frothy  glass. 

Basic pitchstone  from  ^'■ash  bed^'  northeast  of  Meriden. 


SiO- 

TiO, 

COj 

P.O5 

F 

AI2O3 

Fe^Os 

Feo 

NmO 

BaO 

SrO 

CaO 

MgO 

KjO 

NajO 

LijO 

(at  110°  ... 
^     (above  110° 


Per  cent. 
46.86 
1.13 
2.19 
.15 
trace 
13.96 
5.23 
4.67 
trace 
.03 
trace 
9.42 
7.69 
2.02 
1.85 
trace 
1.29 
3.43 

99.92 


ORIGIN  OF  THE   GLASS   AND   MINERALS. 


It  remains  to  consider  the  cause  of  the  extensive  development  of  glass 
in  the  midst  of  the  trap  as  a  result  of  the  introduction  of  water  and  sand  in 
so  great  a  quantity. 

It  might  seem  probable  that  the  introduction  of  so  much  quartz  would 
have  perixdtted  some  solution,  so  that  the  glass,  being  more  acid,  would 
more  easily  take  the  vitreous  form.  The  percentage  of  silica  is,  however, 
somewhat  less  than  in  the  average  of  the  diabase,  and  a  study  of  a  great 
number  of  slides  failed  to  show  any  trace  of  quartz  or  tridymite,  except 
in  a  late  vein  filled  with  coarse  calcite  and  analcite.  Slides  boiled  with 
concentrated  HKO  failed  to  show  any  change. 

It  is  more  probable  that  water  has  been  absorbed  in  such  quantity  as 
to  have  contributed  to  the  observed  result.  While  obsidians  are  water-free, 
pearlstones  average  3  per  cent  of  water,  and  pitchstones  7  per  cent,  while 
the  corresponding  porphyries  average  only  IJ  per  cent. 

It  is  remarkable,  considering  the  quantity  of  water  which  must  have 


438       GEOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 

been  carried  into  the  mass  with  the  mud,  that  there  is  almost  no  trace  of 
amygdaloidal  development.  Only  one  fragment  of  a  trap  inclosed  with 
others  in  a  breccia  contained  small  steam  holes. 

The  collapsed  cavities  with  wrinkled  interiors  and  the  absence  of  the 
common  steam  holes  are  explained  by  the  absorption  of  the  water  by  the 
magma,  and  this  absorption  explains  the  unusually  large  development  of 
basic  glass  in  connection  with  this  exceptional  occurrence.  Above  the 
compact  and  columnar  trap  which  rests  on  this  hydrated  glass  is  the  usual 
coarsely  amygdaloidal  surface  layer  of  the  trap,  whose  moisture  seems  to 
have  no  comiection  with  this  development  at  the  base  of  the  bed.  It  was, 
however,  in  this  surface  amygdaloid  in  the  Deerfield  bed  that  I  found 
perfect  secondary  albite  crystals  resting  on  diabantite  in  the  amygdiiles. 

The  great  abundance  of  calcite  and  its  intimate  admixture  with  the 
other  constituents  are  remarkable.  I  have  elsewhere  given  reasons  for 
thinking  it  in  great  part  formed  during  the  consolidation  and  cooling 
of  the  glass  It  is  consonant  with  this  that  the  feldspars  formed  during 
this  cooling,  especially  those  in  the  spherulites,  are  quite  acid,  while  Hawes 
found  very  basic  feldspars  an  abundant  constituent  of  normal  trap. 

When  these  secondary  feldspars  are  boiled  with  strong  hydi'ochloric 
acid  and  treated  with  fuchsin  there  is  no  trace  of  decomposition,  and  the 
optical  characters  indicate  a  very  acid  feldspar.  The  COg  brought  into  the 
mass  by  the  waters  from  the  coal-bearing  sandstones  below  may  have  taken 
possession  of  a  large  portion  of  the  Ca,  leaving  the  Na  to  go  into  the  newly 
made  feldspar. 

The  similarity  of  this  aqueous  feldspar  to  that  in  a  metamorphic  schist 
is  remarkable,  and  it  is  interesting  to  find  diopside  and  segerine-augite  and 
hematite  formed  with  it,  thus  making  a  very  peculiar  crystalline  schist  in 
a  very  peculiar  position. 

It  is  again  remarkable  that  diabantite  and  its  serpentinous  decomposition 
product  are  rare  in  these  glasses  and  the  associated  traps.  This  militates 
against  the  idea  that  the  peneti-ation  of  the  ground  waters  into  the  liquid 
trap  is  the  cause  of  its  chloritization. 

The  lava  bed  flowed  over  the  muddy  bottom  quite  rapidly,  and  the 
heated  mud  and  water  have  frothed  up  into  the  still  liquid  mass,  causing  an 
intimate  blending  of  sand  and  lava  for  a  thickness  above  the  base  of  the  bed 
of  from  30  to  75  feet  and  for  a  distance,  parallel  to  the  advancing  front  of 
the  sheet,  of  several  miles. 


THE  DEEKFIELD  SHEET.  439 

The  suddeu  introductiou  of  so  large  a  volume  of  water  has  caused  the 
mass  to  cool  as  a  spherulitic  glass  with  a  mimite  crackling,  which  gives  it 
a  pitchy  luster  and  a  large  content  of  water  (4.72  per  cent),  thus  forming  a 
basic  pitchstone,  which  does  not  seem  to  have  been  described  before. 

As  a  further  direct  influence  of  the  water  on  the  lava,  many  abnomial 
forms  of  trap  were  made  locally.  The  liquid  mud  rose  in  the  liquid  lava 
with  many  explosions,  shattering  the  abnormal  mixtui-es  already  solidified, 
and  blending  them  in  still  more  complex  mixtures  while  the  newly  solidified 
glass  was  still  slightly  plastic. 

The  whole  is  cemented  by  the  remnant  of  the  glass,  or  an  aqueo-igneous 
stage  follows  the  igneo-aqueous,  and  a  more  distinctly  hot-water  product, 
consisting  of  albite,  diopside,  hematite,  calcite,  and  segerine-augite,  forms 
the  cement.  This  glass-breccia  is  proved  to  be  an  integral  portion  of  the 
trap  sheet  by  the  fact  that  there  is  a  heavy  basal  bed  of  crystalline  trap 
resting  upon  the  sandstone,  and  the  breccia  grades  downward  into  this 
bed,  as  it  does  also  upward  into  the  overlying  crystalline  trap  which  forms 
the  major  portion  of  the  overflow.  Sometimes  this  basal  bed  is  shattered 
and  its  parts  are  carried  up  into  the  glass  and  rounded  and  filled  with 
superficial  steam  holes  by  remelting. 

CONTACT    OF    THE    SANDSTONE    UPON   THE    DIABASE. 

On  either  side  of  the  mouth  of  Fall  River,  and  for  a  mile  south,  con- 
tinuous outcrop  of  the  upper  contact  is  visible  at  low  water.  The  rather  soft, 
deep-red,  shaly  sandstone  is  wholly  imaltered  and  never  included  in  the  trap, 
while  it  folds  around  all  small  protuberances  of  what  was,  doubtless,  the  old 
ropy  surface  of  a  lava  flow,  its  laminae  thickening  in  the  bottom  of  the  pro- 
tuberances till  they  have  evened  up  the  surface  of  the  ropy  lava,  and  at 
times  fragments  of  the  traps  are  wholly  included  in  the  sand.  The  sand 
even  fills  the  opened  steam  holes.  Just  north  of  the  point  where  the  wood 
road  goes  east  from  the  Sunderland  Hotel  there  is  another  fine  contact  of 
the  sandstone  on  the  trap,  near  its  south  end. 

FALL    RIVER    FAULT. 

On  following  down  the  trap  from  its  north  end  to  the  Connecticut, 
one  finds  that  it  halts  abruptly  at  the  water's  edge  east  of  the  mouth  of 
Fall  River  and  faces  an  island  of  sandstone  which  lies  just  in  its  line  of 
strike ;  but  on  following  the  bed  up  from  the  south,  one  discovers  that  it 


440  GEOLOGY  OF  OLD  HAMPSHIRE  OOTJNTT,  MASS. 

ends  abruptly  in  a  vertical,  northward-facing  wall  165  feet  west  of  the  ter- 
mination of  the  northern  portion  already  noted,  and  on  the  other  side  of 
Fall  River. 

We  notice  that  the  sandstone  resting  on  the  trap  near  the  northern 
terminus  of  the  west  ridge  is  exactly  the  same  soft,  deep-red  shale,  and  that 
it  rests  upon  a  trap  with  the  same  amygdaloidal  texture  and  the  same  min- 
eral contents  as  at  the  south  terminus  of  the  east  ridge.  At  the  same  dis- 
tance from  this  contact  in  either  ridge  the  rock  becomes  suddenly  filled  with 
the  same  chopped-straw-like  forms,  which  may  be  fucoids,  or  indusia  of  the 
insect  found  farther  east  in  the  sandstone,  or,  more  probably,  concretions; 
and  measuring  a  second  distance  we  find  a  thin  bed  of  gray  conglomerate 
interposed  in  the  sandstones  in  both  cases.  The  sandstone  series  thus  agrees 
minutely  on  either  side  the  line,  and  with  the  traps  must  have  been  faulted 
with  the  dip  about  165  feet. 

The  rock  is  intercalated  in  the  sandstone  and  dips  eastward  with  it.  It 
would  seem  to  follow  this  dnection  only  a  little  way  before  coming  to  the 
Fall  River  fault,  as  an  artesian  well  sunk  on  the  east  bank  of  the  river  by 
the  Montague  Paper  Company  (see  "Artesian  wells,"  Chapter  XII)  went 
down  900  feet  below  the  level  of  the  dam,  while  immediately  opposite  on 
the  west,  and  separated  only  by  the  width  of  the  river  (about  1,430  feet), 
the  trap  dips  toward  the  well  with  an  angle  of  32°,  which  would  make  it 
appear  in  the  well  at  894  feet  below  the  surface,  whereas  it  does  appear 
at  585  feet,  making  an  upthrow  on  the  east  of  the  fault  plane  of  209  feet. 

THE    UNITY    OF    THE    SHEET. 

From  its  north  end  to  a  point  just  below  the  lower  suspension  bridge 
at  Turners  Falls,  the  trap  ridge  is  an  inconspicuous  object  seen  from  the 
surface  of  the  high  sands  on  the  west,  and  here  it  is  for  a  distance  entirely 
covered  by  them.  When  it  reemerges  it  has  a  greater  width  and  has 
changed  its  direction  to  southerly.  This  is  my  interpretation  of  the  facts 
at  this  point,  and  I  find  myself  here  again  at  variance  with  the  conclusions 
of  Professor  Davis,  cited  above.  It  is  certain  that  there  is  no  proof  that  the 
trap  from  the  south  runs  by  the  northern  strip  on  the  west,  so  that  the  latter 
could  be  called  a  posterior  range  to  it.  There  is  also  no  conclusive  proof 
that  the  two  parts  of  the  dike  are  united  under  the  sands.  I  think  it  most 
probable  that  they  are.  The  two  are  lithologically  identical,  as  are  the 
sandstones  above  them,  and  the  region  abounds  in  faults. 


THE  DEEEFIELD  SHEET.  441 

Southward  the  trap  rises  higher  aucl  continues,  with  lofty,  nearly 
vertical  walls  on  the  east  and  west,  between  the  river  and  the  town  of 
Greenfield.  President  Hitchcock  quotes  "trap  tuff"  as  constituting,  a  mile 
east  of  Grreenfield,  "a  large  portion  of  the  ledge  of  greenstone,  which  is  in 
places  a  hundred  feet  thick."  This  is  the  great  pitchstone-breccia  at  the 
base  of  the  bed  described  above. 

Across  the  deep  notch  of  the  Deerfield  River  the  sheet  rises  and 
thickens  in  Deerfield  Mountain  and  looks  down  with  vertical  wall  upon  the 
village  of  Deerfield  at  its  foot.  It  shows  just  east  of  the  village  the  finest 
columns  in  the  State,  2  to  3  feet  in  diameter,  and  in  places  distinctly  curved.^ 

Farther  south,  just  before  crossing  the  river,  the  great  sheet  shows, 
from  below  upward,  four  horizons  of  heavy  amygdaloids,  indicating,  doubt- 
less, that  it  is  a  composite  of  as  many  great  lava  flows  in  this  portion  of 
its  extent. 

To  the  south,  in  Mount  Toby,  where  it  is  thinner,  it  is  amygdaloidal  in 
nearly  its  whole  thickness,  while  at  its  north  end  it  is  compact  at  base  and 
heavily  amygdaloidal  in  its  upper  portion. 

PETROGRAPHICAL    DESCRIPTION. 

NORMAL  DIABASE. 

The  rock  is  a  typical  diabase,  ranging  from  aphanitic  varieties  to  those 
where  the  white,  flat  feldspars  are  2  to  4°""  square,  and  from  compact  to  very 
coarse  amygdaloidal.  The  different  veins  are  of  very  uniform  texture  and 
always  in  an  advanced  stage  of  decomposition,  though  appearing  quite 
fresh;  plagioclase,  apparently  of  two  species,  augite,  magnetite,  and  olivine 
are  uniformly  present.     Apatite  can  not  be  detected. 

The  common  plagioclase,  probably  labradorite,  is  always  by  far  the 
most  abundant  constituent,  and  the  angle  of  extinction  of  its  long  rodlike 
crystals  is  commonly  12°.  Several  varieties  of  the  rock  are  subporphyritic 
by  the  development  of  white  spots,  made  up  of  groups  of  stout  crystals  of 
a  second  triclinic  feldspar,  apparently  distinct  from  the  first,  whose  angle  of 
extinction  is  21°.  Both  feldspars  are  thoroughly  decomposed,  commonly 
from  the  center,  and  sometimes  show  only  aggregate  polarization. 

The  augitic  constituent  has  for  the  most  j)art  gone  over  into  a  mixture 
of  green  and  brown  chloritic  minerals,  but.  here  and  there  an  exceptionally 
arge  crystal  remains  in  whole  or  in  part  intact. 

IE.  Hitchcock,  Geol.  Mass.,  1841,  p.  642. 


442       GEOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 

The  rock  at  the  new  cutting  south  of  the  Deerfield  River  and  south- 
ward is  very  fine-grained,  breaking  with  conchoidal  fracture,  dark-gray  and 
compact  at  the  base  of  the  dike,  and  there  distinguished  by  an  abundance 
of  the  well-known  feathery  aggregations  of  magnetite  grains,  while  in  the 
whole  upper  portion  it  is  coarsely  amygdaloidal,  the  amygdules  filled  com- 
monly with  diabantite,  calcite,  or  both — when  one  penetrates  below  the 
deep  layer  of  rusty  scoriaceous  rock  from  which  all  the  secondary  minerals 
have  been  removed — and  here  the  magnetite  is  never  arranged  in  feathery 
groups.  At  the  old  cutting  on  the  other  side  of  the  Deerfield  River,  a  few 
rods  north,  the  rock  becomes  more  granular  in  texture,  and  grayish-  and 
reddish-white  varieties  occur,  subporphyritic  and  abounding  with  flattened 
steam  cavities,  filled  now  with  diabantite.  These  colors  are  arranged  in 
layers,  giving  the  rock  an  indistinct  fluidal  structure.  These  varieties  con- 
tinue northward  and  are  exposed  in  great  force  for  nearly  a  mile  of  fresh 
cuttings  where  the  road  from  Grreenfield  to  Turners  Falls  crosses  the  dike, 
and  from  the  Suspension  bridge,  at  the  end  of  this  road,  along  the  river 
side  for  a  mile  north,  to  the  mouth  of  Fall  River  and  beyond.  Through 
all  this  area  prehnite  and  the  products  of  its  decomposition  occupy  the 
amygdaloidal  cavities  in  very  great  quantity,  accompanied  everywhere  by 
traces  of  copper  minerals  in  place  of  calcite  and  chalcedony,  which  abound 
farther  south.  The  masses  of  native  copper  found  in  the  till  must  come 
from  here. 

The  most  interesting  variety  is  a  very  coarse  one,  abundant  on  the 
Greenfield  road,  which  contrasts  pleasantly  with  the  somber  gray  of  the 
prevailing  types.  Broad  white  plates  of  the  feldspar  stand  out  upon 
a  dark-red  background  of  decomposed  augite,  the'  whole  sprinkled  with 
amygdules  of  prehnite  and  diabantite.  That  this  coarse  variety  is  younger 
than  the  greenish-gray  subporphyritic  trap  is  clear  from  a  large  slab  from 
the  middle  of  the  slope  on  the  Grreenfield  road,  showing  a  contact  of  the  two, 
upon  which  the  latter  is  cut  off  immediately  and  sharply  and  without  change, 
while  the  former  has  a  layer  of  deep-red,  very  fine-grained  rock  IS™"'  wide 
adjacent  to  the  contact  plane.  It  seems  to  me,  however,  to  represent  only 
a  slight  difference  in  age  and  to  be  probably  a  case  of  "schlieren,"  in  the 
sense  of  E.  Reyer.^ 

An  exceptional  rock  occurs  abundantly  in  bowlders  on  the  south  side  of 


1  Theoratisclie  Geologie,  1888,  p.  80. 


THE  DEERFIELD  SHEET.  443 

the  Deerficld  River,  but  I  have  not  met  it  on  the  north  or  in  place.  It  is 
a  clear,  lig-ht-g-ray  rock,  Avith  roundish  blotches  of  white,  and  it  looks  like 
a  weathered  leucitophyre.  Under  the  microscope  the  blotches  are  seen  to 
be  made  up  of  aggregated  stout  crystals  of  plagioclase,  and  the  rest  of  the 
mass  between  of  rodlike  plagioclase  and  magnetite,  with  almost  no  augite. 
The  rare  amygdules  in  this  rock  are  filled  with  a  fine  silky,  radiated 
mineral,  apparently  an  altered  prehnite  resting  upon  diabantite,  or  more 
rarely  lined  with  glassy  crystals  of  albite,  with  datolite,  pyrite,  or  globules 
of  zincblende. 

RED   DIOPSIDB-DIABASK,    WITH  SECOITDAKY  ALBITB. 

Much  of  the  basal  part  of  the  Deerfield  bed  just  north  of  the  Deerfield 
River  is  a  peculiar  rock,  remarkably  different  from  the  usual  monotonous 
trap  of  the  region.  It  has  been  radically  metamorphosed  by  hot  water 
during-  its  cooling.  It  is  a  fresh,  fine-grained,  bi'ick-red  rock,  full  of  small 
cavities  and  scattered  larger  ones,  both  lined  or  filled  with  exquisite  albite 
crystals  large  enough  to  be  easily  studied  with  a  lens  (fig.  24,  C,  p.  422). 
The  feldspars  "of  first  consolidation"  in  the  body  of  the  trap,  which  are 
near  oligoclase,  have  been  floated  to  their  present  place  in  delicate  feathery 
groups.  They  retain  their  sharp  crystal  outlines  and  trace  of  cleavage  and 
multiple  twinning  on  two  bands,  but  have  been  changed  to  a  sericitic  mass 
of  subparallel  scales  and  needles  of  two  kinds,  very  minute  needles  polar- 
izing in  low  colors  0.015°"™  long  and  0.0003°""  wide,  and  brightly  polarizing 
scales  0.04™™  long.     They  seem  to  be  kaolin  and  mica. 

The  ordinary  brown  interstitial  augite  is  wanting,  but  a  few  much 
twinned  idiomorphic  diopside  crystals  occur.  The  above  minerals  are  free 
from  the  very  abundant  hematite  which  in  grains  and  dendritic  growths  fill 
the  second  generation  of  feldspars  and  make  most  of  the  slide  opaque,  and 
which  entirely  replace  the  iisual  black  ores  and  colored  augites.  The 
second  generation  of  feldspars  is  often  in  sheaves  of  parallel  fibers,  one  or 
more  generally  proj  ecting  far  beyond  the  rest.  They  are  heavily  loaded  with 
the  red  rust,  but  often  have  clear  borders  or  the  rust  is  in  a  cross  occupying 
the  diagonals  to  the  square  sections. 

Many  of  the  cavities  are  filled  with  a  fresh  albite  mosaic,  and  this  at 
times  closely  resembles  the  limpid  feldspar  mosaic  of  the  amphibolites, 
being  often  without  twinning  and  showing  the  same  concentric  polarization. 
This  want  of  twinning  is  largely  due  to  the  development  of  the  albite  in 


444       GEOLOGY  OP  OLD  HAMPSHIEE  COUNTY,  MASS. 

mica-like  scales  with  their  M  (010)  faces  arranged  parallel  to  the  section 
plane,  so  that  they  show  no  twinning,  but  give  with  convergent  polarized 
light  a  negative  bisectrix. 

In  some  of  the  large  cavities  a  broad-bladed  mineral,  probably  barite, 
has  formed  in  many  separate  and  parallel  plates,  and  all  these  have  been 
coated  with  albite  and  then  removed  by  solution.  Chalcopyrite  also  appears 
in  these  cavities.  There  is  no  diabantite  nor  any  trace  of  ordinary  weather- 
ing in  the  slide;  and  it  is  probable  that  heated  waters  acting  on  a  magma 
in  which  the  first  feldspars  were  floating  have  decomposed  these,  changed 
all  the  iron  into  hematite,  thus  preventing  the  formation  of  the  dark  augite 
and  the  black  ores,  and  have  then  deposited  the  residuum  of  the  feldspathic 
material  in  the  steam  holes.  Specimens  can  be  obtained  where  the  trap  has 
recently  been  blasted  to  make  way  for  the  electric  road  and  the  fragments 
dumped  on  the  steep  slope  extending  down  to  the  Deerfield  River. 

The  difference  of  the  rock  from  the  normal  diabase  is  shown  by  order 
of  crystallization  of  the  constituents  of  this  and  of  the  normal  diabase. 

Diopside- diabase.  Normal  diabase. 

First  plagioclase.  Magnetite, 

Diopside.  First  plagioclase. 

Hematite.  Second  plagioclase. 

Second  plagioclase.  Augite. 

Steam  holes.  Steam  holes. 

Third  plagioclase.  Diabantite. 

It  is  interesting  to  see  here  the  development  of  the  sericitic  growth  and 
the  albite  mosaic  without  the  formation  of  hornblende. 

The  rock  here  incloses  fragments  of  fine  sandstone  exactly  like  those 
found  at  the  Grreenfield  quarry  about  3  miles  north  on  the  same  dike,  and, 
as  there,  it  is  greatly  baked  and  fused  with  the  trap.     (See  p.  419.) 

PAEAGBNESIS   OF   SECONDAKT  MINERALS. 

During  the  summer  of  1880  a  heavy  cut  was  made  through  the  trap  on 
the  south  side  of  the  Deerfield  River  for  the  extension  of  the  Canal  Railroad, 
which  opened  up  veins  canying  the  usual  trap  minerals  in  great  abundance 
and  beauty.  The  veins  run  nearly  vertical,  with  a  thickness  not  above  4 
inches,  and  they  were  exposed  to  a  depth  of  60  feet.  Later  a  similar  cutting 
along  the  north  side  of  the  stream  and  directly  opposite  afforded  many  large 
cavities  filled  with  the  finest  transparent  datolite  of  unusual  size,  but  lacking 


THE  DEERFIELD  SHEET. 


445 


wholly  the  variety  shown  on  the  sonth  side.     I  have  included  a  detailed 
study  of  these  minerals  in  the  Mineralogical  Lexicon,^  and  give  here — 
1.  The  paragenesis  of  the  stilbite-chabazite  veins — 

1.  Radiated  stilbite.  1-  Prehnite. 

•J.  Chabazite.  2.  Heulaudite. 

3.  Oalcite.  3.  Prismatic  stilbite. 

4.  Pyrite;  or  4.  Chabazite. 

5.  Oalcite. 


2.  A  general  table  of  the 

paragenesis  of  the  minerals  found.     The  old- 

est  is  first,  and  the  overlap  of  the  words  corresponds  approximately  to  the 

overlap  of  the 

minerals: 

Diabantite. 

g 

Albite. 

1 

Prelinite. 

p< 

Bpidote. 

1 

Axinite. 

E 

Tourmaline. 

"3  ^ 

Calcite. 

n 
1 

Fluor. 

1 

Sulphides. 

Pi 

DO 

Datolite. 

■3 

Spbene. 

Calcite. 

Sulphides. 

'Natrolite. 

Stilbite. 

s 

Heulandite. 

Analcite. 

a 

Calcite. 

Fluor. 

p 

Sulphides. 

o 

Chabazite. 

Oalcite. 

Fluor. 

Pyrite. 

rSaponite. 

p. 

Chlorophseite. 

<o    ■ 

ei_,  O 

Kaolin. 

Malachite. 

Limonite. 

1 

.Wad. 

'  Bull.  U.  S.  Geol.  Survey  No.  126,  1895. 


446  GEOLOGY  OF  OLD  HAMPSHIEE  COUYTY,  MASS. 

THE    HOLYOKE    SHEET. 

Situated  a  few  miles  below  College  Hill,  Mount  Holyoke  has  been  for 
many  years  annually  visited  by  me  with  my  classes,  and  has  been  also 
assigned,  part  by  part,  to  small  groups  of  advanced  students  for  their  first 
essays  in  practical  geological  work.  Many  men  who  have  devoted  their 
lives  to  geology  were  of  especial  assistance  to  me  in  making  out  the  struc- 
ture of  this  rugged  and  heavily  wooded  area.^ 

The  great  sheet  of  diabase  which  makes  through  most  of  its  length 
the  crest  of  the  Holyoke  range  is  a  contemporaneous  flow  resting  upon  the 
coarse  granitic  sandstone,  which  it  bakes,  and  it  is  covered  by  exactly 
similar  coarse,  light-buif  sandstone.     (See  PL  IX.) 

In  the  eastern  end  of  the  range  the  bluffs  which  overhang  the  Belcher- 
town  ponds  contain  no  trap,  and  one  must  skirt  the  sandstone  ridge  for  a 
long  distance  westward  before  coming  to  the  first  outcrop'  of  the  volcanic 
rock.  This  emerges  from  the  sands  of  the  post-Glacial  lake  (in  the  roadside 
just  east  of  H.  and  L.  E.  Upham's  house)  midway  on  the  north  slope  of 
the  ridge. 

Curiously,  this  eastern  end  of  the  sheet,  where  it  disappears  beneath 
the  sands,  is  directed  northeast,  while  the  south  end  of  the  great  Deerfield 
bed  in  Mount  Toby  is  directed  southeast,  toward  the  great  core  of  diabase 

'  In  1894  Mr.  BeDJamin  Smitli  Lyman  published,  in  an  article  entitled  "  Some  New  Red  horizons" 
(Proc.  Am.  Philos.  Soc,  Vol. XXXIII,  p.  192),  "a  conjectural  map  of  the  Connecticut  and  Massachu- 
setts New  Red."  This  map  is  said  to  have  been  "  compiled  from  Professor  Emerson's  map  of  the  Massa- 
chusetts New  Red,"  so  far  as  the  part  here  under  discussion  is  concerned.  On  the  same  page  (loc.  cit., 
p.  202)  it  is  stated  that  "the  topography  seemed  to  indicate  clearly  the  necessity  of  reducing  the 
extent  of  the  trap,  in  some  places  very  much,"  and  "in  Massachusetts,  too,  near  Mount  Toby,  and  at 
the  eastern  end  of  Mount  Holyoke,  the  topography  seemed  to  require  the  changes  that  have  been 
made  in  the  mapping  of  the  trap."  As  a  result,  the  trap  is  carried  along  the  bare  sandstone  ridges  to 
the  Belchertown  ponds  and  apparently  doubled  in  a  wholly  inaccurate  way,  while  the  Deerfield  bed  is 
still  more  wrongly  drawn.  The  whole  shows  clearly  the  incapacity  of  the  gentleman  to  interpret 
topography  in  terms  of  geology.  Again,  the  coarse  conglomerates  of  Mount  Toby,  which  my  map 
shows  to  rest  on  all  sides  directly  on  the  crystallines,  is  assigned  to  the  "Gwynnedd  shales"  and  placed 
in  the  upper  half  of  the  series  above  the  "Norristowu  shales,"  to  which  a  thickness  of  6,100J^  feet  is 
assigned.  All  the  fossils  of  the  Trias  are  referred  in  an  indefinite  way  to  the  "Norristowu  shales" — 
that  is,  to  a  horizon  below  the  Moiint  Toby  conglomerates,  which  is  also  wide  of  the  facts.  At  the 
beginning  of  the  article,  in  the  midst  of  several  pages  of  harsh  criticism  of  his  predecessors,  the 
author  says  of  his  attempt,  "There  is  reason  to  hope  that  it  may  keep  well  within  the  not  wholly 
unprecedented  New  Red  proportions  of  2  bushels  of  conjecture  to  2  grains  of  fully  ascertained  fact." 
(Loc.  cit.,  p.  193.)  So  far  as  Massachusetts  is  concerned,  I  think  he  has  hardly  kept  within  the  pro- 
portions he  had  set  himself,  and  this  is  the  more  surprising  as  the  author  is  a  native  and  nominal 
resident  of  Northampton,  which  is  in  sight  of  the  rocks  he  has  mapped  so  incorrectly. 


9 


U.  S.  GEOLOGICAL  SURVEY. 


MONOGRAPH  XXIX.    PL.  IX. 


HOLYOKE  DIABASE  SHEET  ijNTERBEODEOl. 

POSTERIOR  DIABASE  SHEET. 

GRANBY  DIABASE  TUFF. 

BLACK  ROCK  DIABASE  'INTRUSIVE'. 

DIABASE  FULL  OF  GRAINS  OF  OUARTZ,  FELDSPAR,  ETC 


GEOLOGICAL  MAP  AND  SECTIONS  OF  THE   HOLYOKE  AND  POST  ERIOR   DIABASE  SHEETS,  THE  TUFF,  AND  THE  VOLCANIC  CORES 


THE  HOLYOKB  SHEET.  447 

ill  Pelliam,  on  Amethyst  Brook.  The  sheet  mounts  the  hillside  obliquely 
toward  the  west,  and  where  it  reaches  the  crest  of  the  hill  has  a  thickness 
of  about  260  feet,  and  where  it  crosses  the  first  road,  the  Bay  road,  running 
to  Belchertown,  of  about  370  feet.  It  presents  only  alow  bluff  to  the  north 
and  dips  south  with  an  angle  of  25°.  It  does  not  grow  much  thicker  as  it 
is  followed  Avest,  nor  does  the  bluff  become  more  prominent  until,  having- 
passed  the  second  road  over  the  mountain,  it  rises  to  a  much  greater  height 
in  the  long,  flat-topped  ridge  which  is  so  marked  an  object  as  seen  from  the 
north  and  which  is  locally  called  Long  Mountain  or  Flat  Top.  The  crest 
has  had  across  Belchertown  a  height  of  450  to  475  feet  above  the  sea,  but 
rises  in  Long  Mountain  to  a  height  of  600  feet.  This  is  explained  in  part 
by  the  thickening  of  the  bed,  which  measures  here  542  feet  east  of  the 
Granby  road,  612  feet  at  the  eastern  central,  770  feet  at  the  center,  and  824 
feet  at  the  western  central  part  of  the  mountain.  The  last  of  these  measiu-e- 
ments  was  made  carefully  with  a  chain  by  Mr.  W.  E.  Sanderson.  It  would 
seem  that  several  undiscovered  faults  must  have  been  crossed,  as  the  number 
seems  much  too  large. 

This  sudden  elevation  of  Long  Mountain  is  also  partly  explained  by 
the  faults  which  bound  it  on  the  east  and  west  and  present  the  edge  of 
the  sheet  in  this  mountain  at  a  better  angle  for  resisting  the  southward 
movement  of  the  ice.  The  fault  on  the  east  is  beautifully  marked,  runs 
with  the  dip,  and  transfers  the  outcrop  of  the  bed  southward  by  just  the 
amount  of  its  width.  The  second  fault  is  directed  southwesterly,  making  a 
large  angle  with  the  dip,  and  on  its  eastern  side  the  dips  have  more  easting, 
so  that  the  outcrop  of  the  diabase  extends  southwestward  for  a  long  way 
and  ends  in  a  point  far  south  of  the  main  ridge.     (See  PL  IX.) 

Following  the  ridge  a  mile  west  one  sees  a  sharp,  heavily  wooded, 
conical  peak,  locally  called  Rattlesnake  Knob,  which  is  the  next  marked 
peak  after  leaving  Long  Mountain,  and  which  is  a  quite  exact  imitation 
on  a  small  scale  of  the  next  high  peak  to  the  west,  namely,  Norwottock 
or  Hilliards  Knob,  the  highest  point  on  the  ridge  east  of  the  Connecticut. 
To  the  east  of  the  small  cone  is  a  deep,  semicircular  depression,  exactly  like 
one  at  the  western  foot  of  Long  Mountain,  and  like  it  caused  by  a  great 
fault.     In  both  these  depressions  sandstone  forms  the  crest  of  the  ridge. 

Both  these  faults  run  southwest,  and  between  them  an  isolated  section 
of  the  trap  sheet,  called  Bishops  Mountain,  is  placed,  en  dchelon,  running 


448  GEOLOGY  OF  OLD  HAMPSHIEE  COtWTY,  MASS. 

southwest  far  down  behind  the  continuation  of  the  bed,  which,  starting 
again  in  the  small  cone.  Rattlesnake  Knob,  runs  on  westwardly  through 
Norwottuck.     Bishops  Mountain  is  a  high  isolated  ridge.-' 

This  fault  is,  on  the  eastward  face  of  the  small  cone,  marked  by  an 
almost  vertical  wall,  nearly  a  hundred  feet  high,  and  climbing  this  wall 
one  finds  midway  a  narrow  shelf,  composed  of  the  sandstone  resting  against 
the  trap.  The  sandstone  is  not  baked,  nor  is  the  trap  amygdaloidal,  nor 
aphanitic,  but  of  the  grain  usual  to  the  central  portion  of  the  bed.  It  is, 
however,  brecciated  at  the  contact  by  crushing  and  recemented  by  silica, 
as  can  be  seen  by  digging  at  the  southeast  corner  of  the  narrow  flat. 

Westwardly  the  heavy  vertical  bluff  continues,  deeply  notched  at  the 
"Notch"  and  the  "Low  Place,"  until,  after  presenting  for  several  miles  its 
vertical  wall  to  the  north,  it  sweeps  down  in  a  magnificent  section,  nearly 
at  right  angles  to  its  dip,  from  the  height  on  which  the  Holyoke  House 
stands,  past  Titans  Piazza  with  its  fine  columns,  to  Titans  Pier,  where  it 
plunges  beneath  the  waters  of  the  Connecticut  to  rise  on  the  west  side  of 
the  river  to  the  top  of  Nonotuck  in  a  section  which  is  the  counterpart  of  that 
on  the  east. 

The  Notch  is  produced  by  erosion  on  a  northwest-southeast  fault,  with 
upthrow  on  the  east,  which  causes  the  fine  northeast  bluff  of  Bear  Moun- 
tain on  the  west  of  the  notch  road  and  the  equally  marked  southwest  bluff, 
which  stretches  away  southeast  on  the  southern  aspect  of  the  range  east  of 
the  road. 

That  the  Holyoke  and  Mount  Tom  beds  are  connected  beneath  the 
river  admits  of  no  doubt.  As  one  stands  below  Titans  Piazza,  midway  in 
the  Mount  Holyoke  section,  and  looks  across  the  river,  the  Mount  Tom 
section  opposite  is  seen  to  be  the  exact  counterpart  of  the  former,  and  from 
the  two  mountain  houses  which  crown  the  crests  of  the  ridges  on  either 
side  of  the  river  the  massive  beds  sink  down  southwardly,  and  agree  in 
the  character  of  the  sandstone  beneath,  in  the  amount  of  its  baking  by  the 
bed,  and  in  the  character  and  thickness  of  the  trap  itself.  The  Holyoke 
ridge  ends  in  Titans  Pier,  whose  vertical  walls  rise  65  feet  above  the  water, 
and  at  exactly  the  corresponding  point  on  the  opposite  bank  the  trap 
appears  and  runs  west  in  a  heavy  ridge  across  the  low  terrace  flats  and, 
turning,  mounts  up  to  the  crest  of  Mount  Nonotuck  and  forms  the  high 
continuous  ridge  to  its  culmination  in  Mount  Tom. 

1  The  contours  of  the  map  are  here  quite  incorrect. 


THE  HOLYOKE  SHEET.  449 

Seen  from  the  west,  a  marked  depression  and  eastward  recession  of  a 
central  section  of  the  trap  ridge  is  manifest,  and  as  the  smaller  eastern  bed 
was  finely  faulted  at  points  opposite  to  the  extremities  of  tliis  section  and 
the  part  between  the  faults  moved  east,  these  faults  were  prolonged  west- 
erly to  explain  the  structure  of  the  main  bed,  and  I  was  able  by  later 
study  to  locate  them  quite  exactly  on  the  gi'ound.  The  northern  is  very 
plainly  mai'ked  in  the  western  boundary  of  the  main  sheet,  which  bends 
sharply  east  in  an  acute  angle. 

THE  FAULTS  AT  MOUNT  TOM  AND  SOUTHWARD. 

Viewed  from  the  south.  Mount  Tom  is  a  table  mountain,  having  a  nearly 
horizontal  sheet  of  trap,  300  feet  thick,  resting  upon  a  great  pedestal  of  sand- 
stone which  rises  about  900  feet  above  the  sea,  with  vertical  scarp  on  west, 
south,  and  east.  At  the  foot  of  the  eastern  scarp  a  fault  runs  very  obliquely 
to  the  course  of  the  bed,  about  N.  35°  E.,  and  on  the  west  of  this  fault  the 
mass  is  raised  about  650  feet,  so  that  if  one  stands  on  the  road  south  of  the 
mountain  the  trap  seems  to  come  to  a  sudden  end  in  Mount  Tom,  but  turn- 
ing eastward  one  can  traverse  its  whole  width  and  can  follow  it  thence 
south  continuously  across  the  State,  and  can  trace  the  sandstone  north  in 
a  sharp  triangular  projection  sent  in  between  the  two  sections  of  the  trap 
by  the  displacement  of  the  fault.  This  eastward-facing  bluff  of  Mount 
Tom  sinks  northwardly;  but  where  the  fault  crosses  the  river  and  makes 
the  westward-facing  bluff  of  Mount  Holyoke  the  tlu'ow  is  about  the  same. 

At  Titans  Piazza  we  have  strike  N.  85°  W.,  dip  22°  S.,  which  would 
carry  the  base  of  the  trap  far  below  the  level  of  the  river  at  Titans  Pier. 
Since,  then,  the  lower  contact  appears  at  the  water's  edge  at  Titans  Pier, 
another  fault  must  pass  to  the  east  of  this  point,  running  between  the  pier 
and  the  piazza,  with  an  upthrow  on  the  west  of  about  625  feet. 

The  new  Holyoke  reservoir  lies  just  across  the  north  line  of  Holyoke 
in  Northampton,  and  the  wood  road  from  its  north  end  soon  crosses  a  brook 
running  north,  and  here  the  gray  sandstone  rests  against  the  main  sheet  of 
trap,  which  is  brecciated  for  several  feet  down  and  cemented  by  a  fine, 
light-gray  sand  at  the  contact  on  the  fault. 

The  slickensided  fault-wall  has  been  well  exposed  by  the  cut  on  the 
electric  road  just  south  of  the  lower  station  of  the  cable  road  onto  Mount 
Tom;  and  about  5  rods  south  along  the  fault,  where  a  small  brook  comes 

MON  XXIX 29 


450       GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

down  over  the  trap,  above  a  small  quarry,  is  an  excellent  exposure  of  the 
fault  showing  a  marked  brecciation  of  the  adjacent  beds. 

The  ridge  reaches  its  culmination  in  Moimt  Tom  because  of  the  great 
upthrow  on  the  fault  running  at  the  eastern  foot  of  the  mountain,  and  not 
because  of  any  thickenmg  of  the  trap  sheet  there;  it  has  a  thickness  of 
about  250  feet  at  Mount  Nonotuck  and  about  300  at  Mount  Tom.  It  then 
sinks  down  to  a  comparatively  low  level,  but  continues  south  as  an 
unbroken  ridge,  rising  in  Provens  Mountain,  in  Agawam,  to  625  feet,  and 
running,  with  thickness  not  greatly  diminished,  to  the  south  Hue  of  the 
State,  and  upon  Percival's  map  of  Connecticut  it  is  prolonged  without 
interruption  to  the  south  line  of  Simsbury. 

Parallel  to  the  Mount  Tom  fault  run  three  others,  farther  south,  which 
cross  the  trap  ridge  very  obHquely;  and,  which  is  of  more  interest  and 
importance,  all  four  run  parallel  to  the  western  rocky  border  of  the  basin. 
One  forms  a  gap  in  the  range  in  Holyoke  through  which  passes  the  rail- 
road which  comiects  this  town  with  Westfield,  and  this  I  have  called  the 
Holyoke  fault.  The  second  forms  the  notch  for  the  passage  of  the  West- 
field  Eiver,  after  which  I  have  named  it.  The  third  determines  a  notch  in 
the  range  at  the  point  where  it  enters  Connecticut,  and  I  have  referred  to 
it  as  the  State-line  fault.^ 

These  parallel  faults  divide  the  country  into  narrow  orographic  blocks 
which  are  tilted  to  the  east,  producing  the  uniform  easterly  dip;  and,  further- 
more, each  block  seems  to  be  raised  vertically  as  compared  with  its  neighbor 
to  the  east,  a  structure  which  seems  most  marked  in  the  case  of  Mount  Tom. 

This  produces  a  pattern  in  the  boundary  of  the  trap  ridge  on  the  map 
which  is  repeated  at  each  fault.  The  western  boundary  of  trap  on  sand- 
stone below  swings  round  in  sickle  shape  to  meet  the  fault,  while  the  eastern 
boundary  of  sandstone  on  trap  is  transferred  to  the  northeast  along  the 
fault  line.  Thus  the  ridges  are  slightly  echeloned,  ending  in  a  high  rounded 
bluif  on  the  south,  while  the  continuation  of  the  ridge  is  to  be  found  moved 
north  and  east  and  beginning  in  a  sharp  point. 

As  the  fault  lines  run  so  nearly  parallel  to  the  trap  itself,  they  form  the 
boundary  of  the  latter  for  long  distances.  This  is  recognizable  on  the  east 
by  the  fact  that  where  the  sandstone  rests  normally  on  the  trap  the  upper 
surface  is  very  scoriaceous  and  full  of  inclusions;  where  the  fault  boundary 

'  See  pages  370,  476,  for  further  discussion  of  State-line  fault  -where  it  crosses  the  posteiior  dike 
and  the  river  at  the  Holyoke  dam. 


THE  HOLYOKB  SHEET.  451 

is  present  on  this  side,  sandstone  occurs  in  immediate  proximity  to  compact 
trap  for  long-  distances.  On  the  west,  in  many  cases,  if  not  in  all,  vertical 
bluffs  and  "Devil's  Gardens"  of  trap  debris  coincide  with  the  fault  bound- 
aries of  the  trap  along  the  uplifted  edge  of  the  blocks.  The  researches  of  von 
Koenen^  as  to  recent  movements  on  such  fault  planes  suggest  the  possibility 
that  many  of  these  vertical  trap  bluffs  may  be  the  result  of  such  recent 
movements.  I  think  this  consideration  has  sufficient  force  to  deprive  these 
vertical  bluffs  of  any  value  as  measures  of  the  time  since  the  disappearance 
of  the  ice,  as  I  have  attempted  to  use  them  elsewhere.  The  effect  of  these 
faults  is  more  manifest  upon  the  narrow  posterior  bed.     (See  p.  473.) 

The  results  regarding  Triassic  faulting  are  in  accord  with  the  very 
valuable  discoveries  of  Prof.  W.  M.  Davis  in  Connecticut  (p.  377.)  So  far 
as  the  substratum  beneath  the  Triassic  is  regular  and  has  north-south  strike, 
the  faults  agree  therewith.  Where,  under  the  Mount  Holyoke  range,  the 
substratum  is  a  great  granite  massive  and  two  great  trap  plugs  further 
complicate  matters,  the  faults  are  correspondingly  irregular. 

GENERAL  CHARACTERISTICS  OF  THE  SHEET. 

At  the  east  end  the  bed  is  amygdaloidal  in  almost  its  entire  thickness, 
and  greatly  decomposed.  This  general  decomposition  of  the  whole  mass 
is  a  striking  characteristic  of  the  whole  bed,  and  even  where  it  seems  as 
fresh  as  possible,  as  where  it  was  blasted  through  at  the  "Iron  Gate"  (Ther- 
mopylae) for  the  passage  of  the  riverside  road  to  South  Hadley,  the  micro- 
scope shows  it  to  be  deeply  decomposed.  It  presents  far  less  range  and 
variety  of  texture  than  the  Deerfield  bed,  being  mostly  aphanitic  and 
showing  only  a  faint  porphyritic  structure  by  the  development  of  the 
earlier  generation,  of  feldspars  to  distinct  visibility.  Back  of  the  Holyoke 
Mountain  House  and  on  Titans  Pier  it  is  exceptionally  coarse-grained  and 
gabbro-like  in  texture,  the  broad,  flat,  black  sheets  of  pyi'oxene  being  often 
markedly  warped  and  one-half  inch  in  length.  Unlike  the  newer  traps,  its 
fissures  are  cemented  by  quartz. 

Following  the  sheet  westward  the  amygdaloidal  texture  is  confined  to 
the  upper  portion  of  the  bed,  except  where  it  is  under-rolled,  when  a  marked 
steam-hole  structure  takes  its  place  at  the  base  of  the  bed. 

It  is  everywhere,  after  reaching  Its  full  thickness,  rudely  columnar,  and 
at  Titans  Piazza  the  columns  are  of  the  largest  size  and  in  great  perfection. 


'  Jahrbuch  K.  preuss.  geol.  Landesanstalt,  1886,  p.  467. 


452  GEOLOGY  OP  OLD  HAMPSHIEE  COUNTY,  MASS. 

NORMAL  CONTACTS  OF  DIABASE  ON  SANDSTONE. 

East  of  the  Bay  road,  the  most  easterly  road  crossing  the  Holyoke 
range,  no  direct  contacts  are  visible.  Pieces  of  the  sandstone  indurated  by 
the  trap  have  been  found  in  the  neighborhood  of  the  lower  contact. 

At  the  northwest  shoulder  of  Rattlesnake  Knob — the  conical  hill  east 
of  Norwottuck,  or  Billiards  Knob — a  very  interesting  contact  is  exposed. 
If  one  goes  east  from  the  fault  which  limits  the  trap  at  the  east  foot  of  the 
peak,  and  follows  the  contact  as  nearly  as  may  be  across  the  talus  at  the 
north  foot  of  the  peak  to  a  point  below  and  a  few  rods  west  of  where  the 
peak  sinks  down  to  the  ridge  which  connects  it  with  Norwottuck,  one  finds 
a  vertical  wall  of  the  trap  projecting  over  the  sandstone  where  the  contact 
is  exposed.  The  diabase  is  fine-grained,  and  the  dark-red  sandstone  is 
baked  for  3  feet  down  to  an  unusual  degree  into  a  rock  closely  resembling 
a  schalstein. 

At  the  northwest  corner  of  the  sharp  peak  of  Norwottuck,  at  the  comer 
of  a  cleared  field,  a  contact  can  be  observed.  The  sandstone  is  indurated 
for  a  short  distance. 

The  next  point  is  more  accessible,  being  to  the  west  of  and  just  over 
the  Notch  road  at  the  north  corner  of  the  "Devils  Garden,"  where  the  trap 
can  be  seen  from  the  road  below  to  be  overhanging.  Here  the  sandstone 
is  coarse  and  is  darkened  and  indurated  to  a  complete  quartzite  for  a  foot 
down,  and  slightly  vesicular. 

There  is  another  exposure  on  the  south  side  of  the  north  footpath  to 
Mount  Holyoke.^ 

The  next  place  is  just  north  of  Titans  Piazza,  a  place  figured  by 
President  Hitchcock,^  and  here  the  diabase  is  at  its  base  very  black  and 
compact  and  full  of  vertical  steam  holes  a  foot  or  more  long.  The  sand- 
stone below  is  baked  into  a  tough  quartzite  or  hornfels  for  a  foot  down. 

CONTACTS  OP  UNDER-EOLLED  DIABASE  CONTAINING  INCLUSIONS  OP  LIMESTONE, 

A  remarkable  wall  of  trap  is  exposed  at  low  water  of  the  river  at  the 
north  foot  of  Titans  Pier,  just  where  the  Hadley  town  line  reaches  the 
river,  below  a  small  cemetery.     The  contact  is  visible  for  100  feet.     The 


'  E.  Hitchcock,  Am.  Jour.  Sci.,  Ist  series,  Vol.  XIII,  1828,  p.  218. 
2  Final  Report,  Geol.  Mass.,  1841,  p.  640. 


THE  nOLYOKE  SHEET.  453 

coarse-gi'ained,  rusty  sandstone  below  is  but  slightly  indurated,  and  for 
only  a  small  distance.  The  diabase  is  aphanitic  and  full  of  steam  holes 
for  1 3  feet  up,  and  contains  in  great  number  angular  fragments  and  long 
filaments  of  a  drab,  fine-grained,  compact  argillaceous  limestone,  up  to  6 
inches  in  length,  together  with  fragments  of  a  fine-grained  micaceous  sand- 
stone. The  two  are  often  kneaded  together,  as  if  both  had  been  plastic. 
The  lower  foot  of  the  trap  is  quite  free  from  inclusions,  and  the  pores  are 
here  large,  distant,  and  more  like  the  cavities  formed  by  the  upward  motion 
of  the  steam  than  by  simple  expansion. 

Both  these  rocks  are  represented  in  the  Chicopee  shale,  and  this  point 
is  at  the  northern  limit  of  this  series.  They  are  unlike  the  coarse  sand- 
stone on  which  the  trap  rests;  so  that  it  is  not  impossible  that  the  trap  may 
be  slightly  faulted  upon  the  sandstone  at  this  point. 

This  is  the  material  which  was  classified  by  President  Hitchcock  as  a 
variety  of  greenstone,  under  the  title  "indurated  clay,"  and  the  locality 
given  above  is  the  only  one  cited.^ 

PETROGKAPHICAL  DESCRIPTION. 

tJnder  the  microscope  the  limestone  is  fine-grained,  with  many  grains 
of  quartz  as  well  as  of  calcite.  In  a  narrow,  superfcial  layer,  ^""^  wide,  at 
the  contact  of  ti'ap  and  limestone  the  limestone  is  recrystallized  as  a  much 
coarser  and  purer  calcite.  Along  one  portion  of  this  zone  the  cross  sections 
of  distinct,  sharp  scalenohedra  appear,  and  these  are  now  covered  by  a  layer, 
^mm  iii{^^^  of  ^  finely  fibrous  mineral.  Rarely  there  occurs  in  this  zone  a 
long  blade  Avith  rounded  end  extinguishing  longitudinally  and  inclosing 
rounded  grains  of  calcite  resembling  those  included  in  the  Laurentian 
apatites.  The  mineral  seems  to  be  tremolite.  The  calcite  scalenohedra 
rest  on  the  diabase  at  the  contact  line,  and  project  into  the  recrystallized 
zone  of  the  calcite,  where  they  are  surrounded  by  the  colorless  fibrous 
layer  (aragonite?),  which  is  of  constant  thickness,  and  upon  this  rests  a 
botryoidal  layer  of  ankerite  or  siderite  in  simple  rhombohedra,  with  rust 
marking  the  cleavage,  and  above  this  a  coarsely  crystalline  calcite. 

In  the  above  section  the  diabase  is  typical  and  is  unchanged  up  to  the 
contact,  and  the  recrystallized  band  gives  no  evidence  of  high  temperature. 
In  a  second  section,  cut  a  few  inches  from  the  first,  the  results  are  quite 
different.      There   is  no    zone    of  coarser    crystallization    surrounding  the 

1  Kept.  Geol.  Mass.,  1835,  p.  409;  1841,  p.  644. 


454       GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

limestone,  but  here  and  there  a  large  crystal  has  developed  porphyriticallv, 
enveloping  the  dusty  ground  in  which  it  grew.  In  several  cases  five  scale- 
nohedra  are  joined  at  base  to  form  a  star.  In  one  place  is  a  round  section, 
4"™  across,  of  coarsely  granular  and  clear  calcite  without  the  dusty  matter 
of  the  rest  of  the  limestone,  and  with  its  large  grains  untwinned,  which 
projects  half  into  the  limestone  and  half  into  the  trap,  as  if  the  two  had 
been  plastic  together  and  a  steam  hole  had  been  formed  at  the  border. 
Another  oval  body  of  the  same  size  as  the  above  is  composed  of  the  same 
clay-dusted  granular  limestone  as  the  large  fragment,  but  has  a  border  of 
larger  grains,  and,  while  retaining  its  shape  and  individuality,  is  thrust 
a  third  of  its  length  into  the  main  mass,  while  two-thirds  its  length  projects 
into  the  trap.  It  seems  here  also  as  if  the  large  mass  must  have  been 
plastic  and  impressed  by  the  smaller  one.  The  limestone  fragment  itself 
has  straight  sides  and  shows  a  distinct  contact  effect,  its  mass  being  slightly 
reddish,  while  a  border  2™"  broad  is  greenish  and  is  separated  from  the 
reddish  interior  by  a  band  of  black  cubes,  apparently  altered  pyrite. 

The  endomorphic  changes  in  the  trap  are  much  more  marked  than  in 
the  former  case.  A  zone  2^™™  wide  is  made  up  of  a  red-brown  base  in 
which  the  few  and  distant  feldspars  appear  like  windows.  A  broad,  clear, 
brown  halo  surrounds  each  feldspar  and  an  opaque  brown  mass  fills  the 
scanty  interspaces.  This  gives  the  grotmdmass  a  curdled  appearance.  It 
contains  beautifully  sharp  calcite  crystals,  scalenohedi-a  and  rhombohedra. 
With  higher  magnifying  power  the  ground  is  resolved  into  a  fine  hyalopilitic 
groundmass  made  up  of  beaded  threads  m  to  i^™™  across  and  Ij""™  long, 
radiating  in  tufts  from  the  feldspars  and  showing  aggregate  polarization 
and  black  cross.  It  polarizes  in  blue  colors.  This  felt  of  fine  threads  is 
beaded  with  a  black  dust  to  make  the  more  opaque  portion  of  the  ground. 
This  zone  passes  gradually  into  the  normal  diabase. 

A  contact  of  the  trap  with  the  sandstone  below  is  exposed  in  the  road 
leading  up  to  the  Nonotuck  House,  showing  a  distinct  but  not  important 
induration  of  the  sandstone.     It  contains  the  same  inclusions  of  limestone. 

The  diabase  at  its  contact  with  the  sandstone  below,  at  the  northwest 
shoulder  of  the  peak  next  southwest  of  the  Nonotuck  House,  is  for  a  height 
of  7  feet  kneaded  full  of  fragments  of  a  fine-grained  buff  sandstone,  and  the 
trap  itself  is  filled  with  dark-green  amygdules.  The  sandstone  effervesces 
only  at  its  contact  with  the  trap.     The  diabase  is  greatly  decomposed,  only 


THE  HOLYOKE  SHEET.  455 

the  feldspai's  retaining  their  form.  The  amygdules  consist  of  radiated  dia- 
bantite,  so  fine-fibrous  that  it  looks  Hke  an  ohve-green  serpentine,  and  it 
scarcely  polai-izes.  In  it  are  grains  and  crystals  of  calcite,  and,  floating 
freely,  many  small  feathery  albite  groups,  visible  only  with  the  micro- 
scope, and  resembling  those  described  (p.  443)  from  the  .cavities  of  the 
Deerfield  diabase.  They  are  in  twins;  extinction  6  to  9°  on  each  side 
of  twinning  suture.  In  one  case  the  angle  of  extinction  with  the  trace  of 
OP  (001)  measured  on  oo  P  ob  (010)  was  +4°,  indicating  albite. 

Also  where  the  boimdary  of  the  trap  swings  farthest  east  at  the  south 
foot  of  this  peak  the  base  of  the  trap  is  full  of  angular  fragments  of  dove- 
colored  indurated  clay,  calcareous  and  having  minute  muscovite  scales, 
and  the  two  substances  are  molded  together  and  the  trap  is  amygdaloidal, 
as  at  the  occurrence  on  the  south  line  of  Holyoke.  Under  the  microscope 
secondary  plagioclase  rods  like  those  in  the  diabantite  cavities  can  be  seen 
in  this  rock,  and  they  are  visible  as  shining  lines  with  a  lens.  The  trap  at 
contact  shows  a  distinct  endomorphic  change.  The  feldspar  rods  decrease 
in  size  and  number  and  the  magnetite  grains  increase  until  a  black  opaque 
border  2-3"""  wide  intervenes.  In  other  places  the  trap  is  shattered  and  its 
fragments  mingle  with  the  sedimentary  matter  (see  p.  368).  A  further 
contact  occurs  just  north  of  the  Westfield-Holyoke  highway,  directly  west 
of  the  town  line.  Here  the  baking  of  the  sandstone  is  marked,  but  the 
trap  above  does  not  contain  inclusions. 

NORMAL   CONTACT   OP   THE   SANDSTONE   ON   THE  DIABASE. 

At  all  points  where  the  upper  contact  could  be  seen  the  diabase  is 
very  amygdaloidal  and  is  often  finely  filled  with  secondary  calcite  and 
zeolites.  The  sandstones  rest  upon  the  trap,  filling  irregularities,  and  not  in 
the  smallest  degree  indurated  or  in  any  way  showing  heat  effects. 

Dry  Brook,  which  runs  by  Larrabee's  quarry  in  the  extreme  north  of 
South  Hadley,  flows  for  a  long  distance  west  along  the  back  of  the  south- 
ward-sloping trap  sheet,  with  sandstone  for  its  lower  (south)  bank,  and  it 
affords  the  longest  continuous  section  of  the  contact.  Following  it  up 
eastward  over  the  divide  a  similar  valley  runs  east  and  continues  to 
expose  the  same  contact,  and  farther  east  it  is  shown  in  each  brook  gorge 
that  comes  down  the  south  of  the  mountain.  The  amygdules  are  here 
filled  with  natrolite  and  calcite,  and  form  beautiful  objects  under  the 
microscope. 


456  GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

The  above  description  applies  to  all  contacts  from  the  east  end  of  the 
bed  to  the  Connecticut  River  and  from  the  Westfield  River  to  the  south  line 
of  the  State. 

CONTACTS  OP  SANDSTONE  ON  DIABASE  WHICH  IS  KNEADED  PULL  OP  LIMESTONE 

AND  SHALE. 

Between  the  Connecticut  and  Westfield  rivers  fine  shales  rest  on  the 
trap,  and  the  upper  surface  of  the  latter  is  full  of  inclusions  of  limestone  and 
shale.  This  can  be  seen  just  south  of  the  station  of  the  Mount  Tom  Electric 
Road,  but  it  can  be  studied  best  at  Dibbles  Crossing  on  the  south  line  of 
Holyoke,  as  described  below. 

SECTION    OF     TRAP    PILLED    WITH    LIMESTONE    FRAGMENTS    ON    THE    WESTPIELD- 

HOLYOKE    RAILROAD. 

At  the  first  rock  cuttings  in  the  main  trap  sheet  on  the  raih-oad  near  the 
south  line  of  the  town  of  Holyoke  the  upper  surface  of  the  bed  is  exposed 
and  is  covered  by  thin-fissile  argillaceous  sandstones  containing  Pachy- 
phyllum.  For  a  distance  on  the  strike  (north-south)  of  1,475  feet,  and 
with  the  dip  (east-west)  of  200  feet,  the  upper  portion  of  the  bed,  to  a 
thickness  of  6  to  12  feet,  is  so  filled  with  fragments  of  the  clayey  limestone 
and  sandstone  that  everywhere  the  two  rocks  are  present  in  about  equal 
quantity.  The  limestone  is  in  small  pieces,  angular  and  little  altered,  or  the 
pearl-gray  fragments  are  molded  and  kneaded  together  with  the  trap.  It  is 
as  if  the  trap,  plastic  from  heat,  were  molded  together  with  the  marl,  plastic 
from  moisture.  The  trap  is  fine-amygdaloidal,  the  cavities  filled  with 
secondary  calcite  and  diabantite.  In  the  section  figured  on  PI.  Ill,  fig.  4 
(p.  208),  the  trap  is  already  solid;  the  mud  flows  into  its  minute  cavities. 
When  polished  surfaces  of  the  mass  and  thin  sections  are  examined,  the 
fact  of  the  mutual  molding  of  the  two  rocks  is  clearly  established.  (See 
PL  Vlllfe,  figs.  1,  2,  p.  428.) 

With  a  lens  the  limestone  is  seen  to  be  fine-oolitic,  at  times  very  dis- 
tinctly so,  with  round  grains  0.6  to  0.9°"^  in  diameter  and  made  up  of  finely 
granular  material  dusted  with  minute  opaque  grains.  There  is  only  rarely 
a  trace  of  concentric  stracture.  At  times  the  amount  of  clay  becomes  con- 
siderable and  the  fragments  are  of  a  thin-laminated  calcareous  marlite. 
That  this  limestone  was  deposited  in  place  and  has  molded  the  trap  is 


THE  HOLYOKE  SHEET.  457 

entirulv  clear  from  an  inspectiou  of  the  fig-ure,  showing  how  it  surrounds 
nuihitutles  of  the  trap  fragments  and  insinuates  itself  into  all  sorts  of  narrow 
and  tortuous  crevices.  It  can  be  seen  where  the  muddy  mass  has  flowed 
into  steam  holes  broken  into  on  the  surface  of  the  trap,  and  there  is  a  dis- 
tinct fluidal  structure  of  partly  concentric  lines  in  the  mass,  each  bending 
less  deeply  into  the  cavity  than  its  forerunner.  The  limestone  is  in  places 
brecciated  by  the  internal  motion  and  explosions  of  the  mass,  its  fragments 
in  part  rounded  by  solution  and  recemented;  it  is  homogeneous  in  every 
part,  and  shows  no  marked  effects  at  the  immediate  contact. 

If  it  is  clear  that  these  fragments  of  trap  have  been  molded  in  the 
oolitic  mud,  it  is  equally  clear  that  this  mud  has  been  involved  in  the  liquid 
trap.  Indeed,  the  thin  sections  were  made  from  a  point  in  the  wall  of  the 
great  trap  sheet  exposed  in  the  railroad  cutting  at  least  10  feet  below  the 
surface  and  wholly  included  in  the  continuous  mass.  That  the  trap  frag- 
ments were  liquid  when  they  came  in  contact  with  the  limestone  is  shown  by 
the  endomorphic  effects  produced  in  the  trap  itself  at  the  contact.  There 
is  generally  a  thin  film  of  pure  and  transparent  glass  in  contact  with  the 
limestone;  then  comes  a  border,  3  to  5™™  wide,  which  is  dense  black  from 
the  amount  of  fine  magnetite  grains  precipitated  in  a  colorless  ground  and 
contains  exceedingly  minute  feldspar  needles.  In  the  larger  fragments  the 
feldspars  gradually  enlarge  toward  the  center  and  the  magnetite  diminishes 
until  a  normal  trap  results  in  which  the  larger  generation  of  feldspars 
contains  fine  ramose  glass  inclusions,  but  in  fragments  less  than  10""°^  in 
diameter  the  whole  section  is  dense  black.  The  small,  round  steam  holes 
are  much  more  abundant  in  these  borders  than  farther  within  the  normal 
trap. 

Streams  of  the  small  rounded  grains  of  limestone  can  be  seen  penetrat- 
ing the  trap,  running  into  it  for  several  millimeters.  The  grains  are  in  great 
numbers,  at  first  in  contact  with  each  other  and  without  trace  of  intervening 
trap,  and  as  the  stream  is  followed  inward  the  rounded  grains  separate  and 
float  freely  in  the  trap.  They  are  distinguished  from  the  secondary  steam- 
hole  fillings  of  crystalline  calcite  by  being  of  finely  granular  material,  often 
dusted  with  black  trap  grains.  This  black  trap  dust  is  abundant  in  places  in 
the  larger  limestone  masses  and  is  an  indication  of  the  shattering  of  the  hot 
trap  by  the  oolitic  mud.  The  true  steam  pores  are  filled  with  diabantite  or 
calcite  coarsely  crystallized  in  transparent  masses  showing  many  twin  laminae. 


458       GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

The  marl  and  trap  are  often  intimately  mixed  together  like  two  nonmisci- 
ble  fluids,  and  the  dark-gray  or  red-brown  trap  and  the  pale-gray  clay 
rock  produce  the  effect  of  Castile  soap.  Long  filaments  and  stringers  and 
rows  of  bubbles  of  the  clay  go  out  very  generally  from  the  larger  masses  of 
the  clay  rock  into  the  trap  in  a  way  explicable  only  on  the  assumption  that 
a  mass  of  muddy  clay  was  thi'ust  suddenly  into  the  Hquid  trap.  At  the 
north  end  of  the  east  wall  of  the  cutting  is  a  sheet  of  the  clayey  sandstone, 
which  is  about  12  feet  long,  a  foot  wide  at  the  center,  and  tapering  to 
nothing  at  the  ends.  Above  and  below  this  the  trap  is  coarsely  amygda- 
loidal,  or  rather  abounding  with  rounded,  beaded,  and  variously  lobed 
cavities,  which  are  filled  with  the  gray  mud.^  Some  of  the  pores  were  left 
empty  or  only  partly  filled  by  the  mud,  and  these  are  filled  with  white 
infiltrated  calcite,  making  a  striking  contrast.  In  many  cases  it  can  be 
seen  that  the  mud  has  risen  from  the  stratified  mass  of  the  argillaceous  rock 
to  form  and  fill  the  cavities.  That  the  bubble-like  masses  of  mud  have 
thus  risen  from  this  larger  mass,  and  that  they  are  regularly  disseminated 
in  the  trap  and  are  not  simply  the  filling  of  supei-ficial  steam  holes,  can  be 
clearly  seen,  and  the  trap  can  be  chipped  off  and  layer  after  layer  of  the 
gray  drops  seen  to  be  isolated  in  the  trap  (see  PL  VIII&,  fig.  1,  p.  428). 

In  one  case  there  can  be  seen  at  the  height  of  one's  eye,  at  the  south 
end  of  the  west  wall,  a  series  of  blocks  filled  with  drops,  and  the  mud  mass 
from  which  they  stream  can  be  seen  below,  while  now  the  mass  containing 
these  mud  amygdules  is  itself  shattered  and  its  fragments  cemented  by 
more  of  the  same  mud  (see  PI.  Ylllh,  fig.  2).  In  other  places  a  thm,  gray, 
laminated,  sandy  shale  is  confusedly  mingled  in  the  trap,  its  layers  being 
greatly  warped  and  twisted.  Under  the  microscope  the  mixture  can  be 
seen  to  be  still  more  intimate,  and  while  there  was  often  a  complete 
emulsion  of  the  two  nonmiscible  fluids  there  is  only  a  shght  chemical 
action  discernible.     Only  a  microscopic  layer  of  recrystallized  carbonates 

appears.^ 

In  other  cases  the  whole  wall  has  a  coarse,  conglomeratic  look,  rounded 


I  The  later  infiltration  of  calcite  has  changed  this  mud  into  a  massive  gray  rock  exarjtly  like  the 
claystones  so  common  in  the  Champlain  clays. 

■^If  anyone  visits  this  most  interesting  locality,  which  is  situated  4  miles  from  Holyoke,  on  the 
road  to  Westfield,  he  will  find  that  the  ridge  running  from  the  Dibble  house  south  to  the  next  house  is 
cut  by  the  railroad,  showing  the  trap  and  the  sandstone  above.  In  the  swale  west  of  this  small  ridge  is 
a  fault,  which  can  be  seen  in  the  brook  directly  behind  the  second  house.  West  of  this  fault  the  series 
is  repeated,  and  the  broad  surface  of  the  trap  for  a  mile  north  is  filled  with  the  foreign  material. 


THE  HOLYOKE  SHEET.  459 

portions  of  the  trap  as  large  as  a  fist  being-  wrapped  around  by  thick  flakes 
i>f  tlie  thin-flssile,  sandy  shale,  as  if  balls  of  putty  had  been  separated  by 
being  folded  in  thick  wads  of  wet  wrapping  paper. 

Above  this  intimate  mixture  a  few  angular  fragments  of  scoria  are 
inclosed  for  a  foot  or  two  in  the  thin-bedded  sandstones.  This  layer  can  be 
followed  north  10  miles  wherever  the  upper  surface  of  the  trap  is  exposed. 

Another  contact  of  the  sandstone  upon  the  trap  occurs  on  the  West- 
field-Holyoke  highway,  just  where  it  crosses  a  brook,  and  this  is  the  most 
southern  point  where  the  trap  contains  limestone  inclusions  at  its  surface. 

President  Hitchcock  plainly  refers  to  a  further  effect  of  the  trap  farther 
south  on  this  line,  in  West  Springfield,  at  a  place  which  escaped  my  obser- 
vation, when  he  speaks  of  the  limestone  in  contact  with  the  trap  being 
converted  to  "tripoli"  and  in  part  made  brittle  as  glass.^ 

MAGMATIO   DIFPEEENTIATION. 

Many  fragments  of  the  trap  which  were  inclosed  in  the  mud  while 
still  molten  are  bordered  with  black  from  the  concentration  of  the  iron  in 
feathery  groups  of  twinned  octahedra  of  magnetite.  This  illustrates  on  a 
small  scale  a  process  which  has  been  the  subject  of  much  study — the  differ- 
entiation of  a  molten  magma  into  a  more  basic  portion,  which  seeks  the 
cooled  outer  surface,  and  a  more  acid  one,  which  remains  at  the  center. 
When  this  process  is  carried  to  its  limit  the  centers  of  the  fragments 
become  white  and  free  from  iron  and  iron-bearing  minerals,  and  the  frag- 
ments of  white  trap  described  on  page  365  seem  to  have  been  thus  formed. 
They  are  found  only  in  this  contact  layer  and  in  the  sandstone  immediately 
above  it. 

ORIGIN  OF   THE   CLAY   AND   MARL   DEPOSITS. 

It  is  hard  to  explain  how,  over  a  portion  of  the  surface  of  the  great 
sheet,  so  large  a  quantity  of  laminated  marl  can  have  been  deposited  and 
then  become  so  regularly  and  deeply  intermixed  with  the  trap.  It  seems 
most  probable  that  the  central  currents  carried  the  mud  out  over  the  sheet 
while  it  was  still  moving,  and  filled  its  brecciated  surface,  and  that  the  mud 
flakes  sank  down  at  times  into  the  still-liquid  trap  in  such  quantity  that 
they  were  merely  indurated  and  cemented  by  the  small  quantity  of  the 
diabase. 

'Geol.  Mass.,  1835,  p.  433;  1841,  p.  659. 


460  GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

The  thick  trap  sheets  flowed  out  over  the  muddy  bottom  of  the  bay, 
and  their  heat  produced  strong  upward  convection  currents  and  corre- 
spondingly strong  indi'afts  from  the  sides,  which  carried  muddy  waters 
out  over  the  surface  of  the  trap  while  it  was  still  flowing  and  covered  it 
with  a  quantity  of  calcareous  mud  out  of  proportion  to  what  would  have 
been  carried  in  the  same  time  by  the  normal  currents.  I  have  seen  sheets 
of  newly  solidified  lava  careen  and  slide  beneath  the  liquid  mass  at  Kilauea, 
and  the  sheets  of  mud  and  lava  may  have  thus  become  variously  mingled 
here,  producing  the  results  described  above.  The  surface  of  the  Holyoke 
trap  sheet  is  filled  with  fine  mud  just  as  far  north  as  the  fine  Chicopee 
shales  extend;  and  farther  north,  where  the  sheet  flowed  over  coarse 
gravel,  nothing  of  the  kind  occurred,  because  the  coarse  gravel  could  not 
be  thus  carried  out  over  the  thick  sheet. 

ON  THE  UNDER-ROLLING  OF  THE  SOLIDIFIED  SURFACE  OF  THE  TRAP. 

The  appearance  of  the  same  layer  at  the  base  of  the  trap  sheet  is 
explained  by  the  under-rolling  of  the  newly  solidified  surface  of  the  sheet, 
as  when  a  carpet  is  unrolled  on  the  floor  what  was  on  top  descends  along 
the  front  and  comes  to  lie  inverted  beneath. 

Thus  the  porous  mud-filled  surface  came  to  form,  inverted,  the  base 
of  the  bed,  and  to  rest,  though  filled  with  fine  mud,  upon  the  coarse  sand 
onto  which  the  sheet  had  advanced.-' 

'I  have  already  reported  very  briefly  upon  this  occurrence  (Am.  Jour.  Sci.,  3d  series,  Vol.  XLIII, 
p.  147);  too  briefly,  it  would  seem,  as  the  facts  given  were  wholly  misunderstood  and  incorrectly 
quoted  by  Professor  Dana  and  made  to  do  duty  in  proof  of  the  laccolithic  origin  of  the  Mount  Tom 
trap  sheet.  In  his  Manual  of  Geology,  on  page  805,  he  says :  "The  limestone  had  been  torn  off  from  a 
layer  not  visible  in  the  section." 

This  was  the  very  point  I  was  trying  to  disprove,  by  showing  both  that  there  was  no  bed  in  the 
older  rocks  of  the  region  from  which  any  such  material  could  be  derived  and  that  the  shapes  of  the 
inclusions  were  not  such  as  would  be  possible  in  solid  rock  torn  oft'  from  the  walls  of  the  fissure 
through  which  the  lava  flowed,  since  it  was  in  thin  filaments  and  flowed  in  to  fill  all  the  open  steam 
holes  of  the  trap  fragments. 

On  the  next  page,  806,  he  says :  "A  laccolithic  origin  and  the  abrasion  of  the  underlying  sand- 
stone are  indicated  by  the  occurrence  of  breccia  beneath  the  trap,  and  especially  by  the  limestone 
chips  in  the  lower  part  of  the  mass  of  the  trap,  and  also  over  its  upper  surface,  as  described  by 
Emerson.  A  bed  of  limestone  was  evidently  divided  by  the  advancing  tongue  of  melted  trap,  part 
being  left  below  and  the  rest  above.  As  Emerson  observes:  'The  facts  prove  that  the  heavy  trap 
flowed  over  the  sandstone,  abrading  and  tearing  it.'" 

This  was  plainly  quoted  from  a  very  dim  recollection  of  the  article  in  question.  There  is  no 
breccia  beneath  the  trap.  The  inclusions  can  not  be  called  chips,  and  there  is  not  the  slightest 
evidence  that  the  melted  trap  has  split  asunder  a  bed  of  solid  limestone.  I  have  not  made,  in  the 
article  cited  or  elsewhere,  the  observation  quoted  in  the  last  sentence,  since  the  facts  all  prove  exactly 
the  opposite.     I  know  of  no  facts  favoring  a  laccolithic  origin  of  the  Holyoke  trap  sheet. 


THE  HOLYOKE  SHEET.  461 

At  every  point  where  the  surface  of  the  trap  sheet  can  be  inspected, 
fniiii  where  it  crosses  the  Connecticut  to  where  it  crosses  the  West- 
tieUl-Holyoke  Raih'oad,  it  has  included  a  great  number  of  fragments  of 
marly  limestone  and  indurated  clay,  and  the  trap  and  limestone  are  often 
kneaded  together.  Within  the  same  limits  the  base  of  the  trap  repeats  all 
tlie  peculiarities  of  the  surface.  It  is  amygdaloidal  for  about  the  same 
thickness  and  in  the  same  way;  the  same  dove-colored  limestone  occurs 
blended  with  the  trap  in  the  same  way;  and  the  subjacent  arkose  is 
almost  wholly  unaffected  by  heat.  The  300  feet  of  trap  have  not  pro- 
duced so  much  effect  as  is  often  seen  upon  the  border  of  a  10-foot  dike. 
This  is  best  studied  at  the  river's  edge  at  the  north  foot  of  Titans  Pier. 
On  the  other  hand,  where  the  molten  surface  of  the  trap  sheet  has  come 
in  contact  with  the  sands  of  the  sea  bottom,  as  at  Titans  Piazza,  100  rods 
north,  the  trap  is  aphanitic  at  the  contact,  but  pierced  by  great  vertical 
steam  holes,  and  the  sandstone  is  greatly  baked.  It  seems  that  the  broad 
submarine  trap  sheet  moved  slowly  westward,  its  incrusted  surface  being 
covered  by  a  fine  marly  clay  deposit  which  was  in  places  desiccated  and  _ 
molded  together  with  the  still  plastic  trap,  and  that  the  surface  was  car- 
ried forward  to  be  rolled  over  the  front  and  become  the  bottom  along  a 
length  of  about  10  miles.  The  limestone  and  marlite  inclusions  of  the 
surface  and  base  of  the  trap  have  been  described  in  detail  above  and  their 
identity  established,  and  similar  cases  of  under-rolling  of  the  Deerfield  dike 
and  of  the  posterior  dike  have  been  given  elsewhere.-' 

PETROGRAPHICAL   DESCRIPTION    OF   THE   NORMAL  DIABASE. 
GENERAL   DESCRIPTION. 

The  rock  is  so  monotonously  uniform  in  all  its  characteristics  that  much 
repetition  will  be  avoided  by  giving  first  a  general  description  of  the  com- 
mon type  and  then  following  this  by  a  special  discussion  of  the  peculiarities 
of  separate  occurrences. 

The  rock  from  the  "Iron  Grate,"  or  Thermopylae,  where  a  passage  has 
been  blasted  through  a  projection  of  the  Holyoke  sheet  for  the  river  road 
to  South  Hadley,  near  Titans  Pier,  coming  from  near  the  middle  of  the 
sheet,  is  an  especially  fresh-looking  variety,  and  may  serve  as  the  new  type 
for  general  description. 

1  See  pages  419,  470. 


462       GEOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 

It  is  a  dark-gray,  almost  aphanitic  rock,  with  broad  conchoidal  fracture 
and  without  any  tinge  of  red  or  brown  in  its  color.  It  is  faintly  subpor- 
phyritic,  and  with  a  lens  the  scattered,  minute,  squarish  feldspar  cross  sections 
appear,  and  at  times  a  triclinic  striation  can  be  observed.  At  times,  also, 
one  detects  a  black  cleavage  surface  of  augite,  but  only  with  difficulty. 

Under  the  microscope  the  rock  is  seen  to  be  a  typical  diabase,  the 
network  of  elongate  feldspars  inclosing  the  shapeless  masses  of  augite. 
Two  generations  of  feldspar,  augite,  magnetite,  and  apatite  make  up  the 
constituents. 

The  larger  feldspars  of  earlier  generation  are  distantly  scattered  in 
the  field  in  squarish  crystals  or  crystal  groups,  and  measure  about  a  mil- 
limeter across,  and  this  is  by  far  the  commonest  size  in  all  the  slides  I 
have  examined.  They  often  show  indication  of  transportation,  being 
broken,  or  showing  undulatory  extinction,  or  having  an  external  band 
which  extinguishes  diiferently  from  the  central.  A  delicate  zonal  struc- 
ture is  at  times  present,  or  the  center  is  full  of  opaque  grains  and  the  outer 
.portion  limpid.  These  latter  structure  forms  are  more  common  in  the  dikes 
than  in  the  two  large  beds.  The  twinning  striation  is  often  interrupted  and 
distant,  so  that  quite  broad  patches  belong  to  a  single  individual.  At  the 
type  locality  these  large  crystals  are  exceptionally  fresh  for  specimens  out 
of  the  large  trap  beds.  They  are,  however,  largely  decomposed  into  a 
mass  of  shapeless,  brightly  polarizing  scales,  apparently  micaceous,  while 
more  commonly  both  the  generations  of  feldspar  are  decomposed  into  a 
fibrous  saussuritic  mass. 

In  a  long  series  of  observations  of  the  extinction  angle  of  porphyritic 
crystals  from  every  part  of  the  valley,  more  than  half  the  angles  obtained 
were  about  31°.  This  would  indicate  strongly  that  the  feldspar  was 
anorthite,  which  would  agree  with  the  results  obtained  by  Mr.  Hawes  (cited 
below,  p.  464)  in  an  analysis  of  the  porphyritic  crystals  of  a  dike  cutting 
West  Rock  in  New  Haven.  I  may  recall,  also,  Hawes's  suggestion  that  the 
more  difficult  fusibility  of  anorthite  may  favor  its  earlier  crystallization. 

The  second  generation  of  feldspar,  which  forms  the  latticework,  is 
lath-shaped,  often  with  ragged  ends  and  notched  and  irregular  sides,  and 
averages  0.1™™  in  length,  though  it  is  subject  to  more  fluctuation  than  the 
larger  group.  Its  extinction  angles  vary  from  12°  to  26°,  which  would 
best  comport  with  the  composition  of  labradorite.     The  rock  under  special 


THE  nOLYOKE  SHEET.  463 

discussion  is  one  of  the  freshest-looking  in  the  valley,  and  yet  it  is  some- 
times impossible  to  find  in  a  slide  a  single  feldspar  on  which  one  can 
observe  the  extinction,  so  decomposed  are  they,  and  the  sei'ies  of  which 
the  extremes  are  given  above  are  taken  from  the  whole  length  of  the 
valley. 

The  augite  is  strictly  subsequent  to  the  lath-shaped  feldspars  and 
pi'esents  little  that  is  specially  noticeable,  though  oftentimes  it  is  less 
decomjiosed  than  the  feldspars.  It  differs  thus  in  the  large  sheets  from 
the  diabase  of  the  tuff  above  and  of  the  newer  dikes,  where  the  augite  is 
often  porphyritic  and  contemporaneous  with  the  earlier  feldspars. 

I  have  in  many  places  noted  olivine  with  a  query;  but  on  reviewing 
the  whole  series  of  slides  I  have  not  been  able  to  find  either  the  unchanged 
mineral  or  any  serpentine  or  hematite  patches  which  would  seem  to  have 
been  derived  from  it  at  the  locality  under  consideration  or  in  either  of  the 
large  trap  sheets.  In  the  dikes  in  the  gneiss  and  in  the  newer  dikes  in  the 
sandstones  it  occurs,  and  it  may  be  wanting  in  the  large  beds  only  because 
of  their  advanced  state  of  decomposition. 

Magnetite  is  uniformly  distributed,  always  rather  but  never  very 
abundant,  generally  quite  well  crystallized.  The  delicate  featherwork  of 
beaded  octahedra  is  especially  abundant  at  the  base  of  the  great  bed  at  the 
contact  on  sandstone  just  north  of  Titans  Piazza. 

Apatite,  never  abundant,  is  rarely  to  be  detected  except  piercing 
magnetite. 

There  is  no  trace  of  groundmass  discernible  between  the  constituents; 
rounded  or  pear-shaped  blebs  of  glass  appear  in  the  older  feldspars. 
Cavities  filled  with  diabantite,  rust,  calcite,  and  zeolites  are  not  wanting, 
even  in  the  wholly  compact  rock  we  have  chosen  for  discussion,  but  they 
are  very  minute.  Sections  from  the  upper  surface  of  the  dike  where  it 
is  cut  by  Dry  Brook  in  the  northwest  of  South  Hadley  exhibit  very 
beautiful  amygdules,  showing  from  without  inward  diabantite,  calcite,  and 
radiated  natrolite. 

CHEMICAL    COMPOSITION. 

In  1838  President  Hitchcock  analyzed  the  much  decomposed  and 
amygdaloidal  trap  from  the  east  end  of  Mount  Holyoke  with  the  result 
shown  in  column  1.^     In  1875  Dr.  G.  W.  Hawes  published  analyses  of 

1  Economic  Geology,  p.  135. 


464 


GEOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS, 


the  compact  trap  from  Mount  Holyoke  (columns  2  and  3),  and  a  mean  of 
the  same  (column  4):^ 

Analyses  of  trap  from  Mount  Holyoke. 


1. 

2. 

3. 

4. 

SiO.2 

53.70 
13.00 

52.70 
14.11 
9.78. 
1.87 
0.45 
9.36 
6.42 
2.54 
0.89 

52.65 
14.17 
9.80 
2.03 
0.44 
9.39 
6.35 
2.57 
0.87 

52.68 
14.14 
9.79 
1.95 
0.44 
9.38 
6.38 
2.56 
0.88 

AhO, 

FeO                       

PejOs        

21.00 
0.19 
0.70 
0.15 

MnO         

CaO 

MeO     

NajO     

KjO                               

H2O                       

8.50 
2.76 

Is                        

1.61 

1.58 

1.60 

100. 00 

99.73 

99.85 

99.80 

THE   UPPER   OR   POSTERIOR    SHEETS   AND    ITS   FEEDING   DIKES. 

This  bed  (see  PI.  IX,  p.  446)  runs  from  a  point  on  the  Connecticut 
River  about  a  mile  below  the  Mount  Tom  station,  parallel  with  and  about 
a  half  mile  east  of  the  Holyoke  range,  to  and  beyond  the  south  line  of  the 
State,  while  its  great  irregular  feeding  dike  is  about  2  miles  south  of  Smiths 
Ferry  and  just  east  of  Mount  Tom,  where  on  the  map  the  outcrop  swells 
out  suddenly.  It  is  locally  known  as  Little  Mountain,  and  forms  the  culmi- 
nating point  of  Forest  Park,  to  which  the  Electric  Road  runs  from  Spring- 
field and  Holyoke. 

The  trap  sheet  shows  the  low  easterly  dip  of  the  sandstone,  in  which  it 
lies  at  a  horizon  about  '600  feet  above  the  Holyoke  bed,  though  north  of 
Mount  Tom  the  two  beds  seem  to  be  much  nearer  because  of  the  Mount 
Tom  fault,  which  at  the  cut  south  of  the  Mount  Tom  Electric  Railroad 
station  brings  them  apparently  within  30  feet  of  each  other.  The  bed  is 
thick,  but  does  not  seem  to  extend  east  of  the  Connecticut,  where  the  tuff 
rests  directly  on  the  sandstone.     Yet  an  inspection  of  the  map  may  leave 

1  Am.  Jonr.  Soi.,  3d  series,  Vol.  IX,  1875,  p.  186. 

^  Called  thus  by  Percival  in  The  Geology  of  Connecticut,  because  the  trap  ridges  face  west  and 
subordinate  ridges  often  appear  before  and  behind  the  main  one. 


THE  POSTERIOR  SUEET.  465 

the  impression  that  it  extends,  at  least  in  a  fragmentary  way,  far  east.  The 
long  eastern  projection  of  the  Black  Rock  plug  (see  PI.  IX,  p.  446)  and  the 
one  east,  and  the  string  of  smaller  })lugs  elongate  east  and  west,  seem  to 
be  parts  of  it.  They  are,  however,  true  intrusions,  and  their  elongation 
seems  rather  to  indicate  the  existence  of  a  common  ancient  and  deep-seated 
rissuro  through  which  they,  have  been  extruded.  This  is  proved  by  the 
fact  that  they  cut  directly  across  the  beds  of  the  sandstone  below  the  tuff, 
the  tuff  itself,  and  the  sandstone  above,  while  west  of  the  river  the  tuff 
rests  directly  upon  the  posterior  sheet. 

The  sheet  appears  first  as  a  great  reef  projecting  into  the  Connecticut 
a  mile  below  Moimt  Tom  station,  its  northern  portion  fine-grained  and  col- 
umnar, its  southern  coarse  and  in  great  blocks,  and  is  doubtless  continuous 
beneath  the  sand  southwest  to  the  interesting  outcrop  at  Lymans  Crossing 
(the  first  crossing  below  Mount  Tom  station),  where  a  wall  of  trap  is  exposed 
in  the  railroad  cut.  The  northern  jaortion  of  the  cut  is  rudely  columnar 
trap,  with  an  irregular  surface  dipping  about  35°  SE.  Resting  upon  this 
surface  is  a  coarse  trap  agglomerate,  consisting  of  blocks  a  foot  across  and 
a  fine  sandy  paste,  in  which  many  flakes  of  graphite  appear.  This  is  the 
normal  relation  of  the  tuff  to  the  posterior  sheet  for  a  long  way  south. 

A  rod  south  of  this  tuff  is  an  outcrop  of  trap  which,  from  its  great  fresti- 
ness  and  compactness,  and  from  its  containing  inclusions  of  coarse  amyg- 
daloid from  the  tuff,  I  associate  with  the  Burnt  Mill  plug  just  south,  which 
interrupts  the  sheet  at  this  point.  A  few  rods  south  of  the  crossing  a  brook 
crosses  the  road,  and  on  it  is  the  ruin  of  Aldrich's  leather  mill,  burnt  many 
years  ago.  The  brook  flows  east  along  the  course  of  a  transverse  fault,  and 
at  and  below  the  dam  can  be  seen  very  finely  the  outcrop  of  an  intruded 
trap  mass,  which  clearly  cuts  across  the  sandstones,  bakes  and  twists  them, 
and  extends  west  along  the  north  side  of  the  mill  pond.     (See  p.  494.) 

South  of  the  brook  and  the  fault  the  outcrops  are  continuous,  and  the 
posterior  sheet  can  be  seen  to  be  wholly  independent  of  the  core  which  crops 
out  north  of  the  stream  at  the  dam.  Commencing  at  the  railroad  culvert 
over  the  brook,  the  sandstone  can  be  seen  on  the  south  side  of  the  brook  in 
contact  with  and  beneath  the  trap  of  the  posterior  sheet  and  having  the 
unusually  steep  dip  of  60°  SE.  beneath  the  trap  because  of  the  fault.  From 
this  point  the  sandstone  can  be  followed  along  the  south  bank  of  the  brook 
contuiuously,  past  the  mill  and  the  pond.     It  dips  regularly  to  the  southeast 

MON  XXIX 30 


466 


GEOLOGY  OP  OLD  HAMPSHIEE  COUNTY,  MASS. 


-     i>    i 


a 


6f?^ 


wiro 


beneath  the  trap  (Avhich  has  only  sHghtly  indurated  it),  and  thus  sepai-ates 
it  completely  from  the  intrusive  trap  of  the  plug-  north  of  the  brook. 

The  removal  of  the  mill  and  dam  has  improved 
the  outcrop  greatly  and  disclosed  a  quite  sharp  anti- 
cline of  the  sandstone  beneath  the  ti-ap  in  the  south 
bank  of  the  brook,  which,  as  the  dip  of  the  sandstone 
is  very  low  to  the  east,  and  the  slope  of  the  hill  is 
in  the  same  direction,  has  the  effect  to  very  greatly 
increase  the  width  of  the  exposure  of  the  trap, 
although  the  sheet  is  only  35  to  40  feet  thick  here. 
The  half  of  this  anticline  as  formerly  exposed 
seemed  to  show  the  trap  resting  directly  on  the 
basset  edges  of  the  sandstone  beds,  and  this,  taken 
with  the  unexplained  greater  width,  made  it  seem 
probable  that  the  trap  had  broken  through  here.^ 
This  anticline  seems  to  cause  the  greater  Avidth  of 
the  trap  outcrop  south  nearly  to  Smiths  Ferry. 

From  the  burnt  mill  the  outcrop  of  the  upper 
bed  extends  southward  as  a  prominent  ridge  just 
west  of  the  river  road  and  separated  b}^  a  deep 
valley  from  the  corresponding  ridge  of  the  Holyoke- 
Mount  Tom  bed  to  the  west.  In  the  steep  west- 
ward declivity  of  this  ridge  the  contact  of  the  trap 
on  the  sandstone  beneath  can  be  found  in  many 
places,  and  the  sandstone  is  indurated  for  a  small 
distance  downward  and  rarely  sends  up  a  steam 
hole  into  the  trap  above.  The  trap  is  covered  by 
the  heavy  tuff  beds,  which  seem  in  the  neighborhood 
of  the  burnt  mill  to  be  blended  with  the  trap  itself, 
as  if  it  had  fallen  upon  the  latter  while  it  was  still 
molten,  so  that  it  is  hard  to  mark  the  true  bound- 
ary, but  no  trace  of  such  blending  could  be  detected 
in  slides  cut  for  the  pui-pose. 

The  narrowing  of  the  trap  upon  the  map  is 
due  to  the  westward  advance  of  the  tuff  upon  it,  by  the  elevation  of  the 
ridge,  so  that  it  outcrops  in  the  steep  westward-facing  bluff. 


'  E.  Hitchcock,  Geol.  Mass.,  1S35,  p.  429;  1841,  p.  656. 


THE  POSTERIOR  SHEET.  467 

Just  northwest  of  the  Smiths  Ferry  niih-oad  station  the  trap  is  faulted 
shg-htly,  the  south  side  being  moved  a  few  rods  westward,  and  in  the  low 
place  in  the  ridge  thus  formed  the  sandstone  approaches  within  80  rods  of 
the  railroad. 

THE  (iUEAT   WIDENING   OF   THE   TRAP   AREA  AND  THE   PEEDIVG   THROAT 

UENEATH. 

A  mile  south  of  Smiths  Ferry  the  trap  widens  to  a  triangular  surface, 
a  half  mile  on  a  side,  and  the  ridge  reaches  its  greatest  height,  rising 
westerly  from  the  river  to  its  crest  in  Little  Mountain  (now  marked  by 
the  highest  lookout  tower  in  Forest  Park)  and  sinking  bj'-  a  vertical  wall  to 
the  valley  which  separates  it  from  the  Mount  Tom  trap  ridge.  (See  PI. 
IX,  p.  446,  northeast  of  Mount  Tom.)  Along  the  western  edge  of  the 
expanded  area  the  thin  trap  sheet  still  rests  normall}^  on  the  sandstone, 
and  on  the  eastern  edge  is  covered  by  the  tuff,  and  its  great  width  is  due 
to  the  fact  that  it  dips  with  the  slope  of  the  hill  east  from  its  crest.  In  the 
deep  inlets  of  sandstone  running  down  into  the  trap  from  the  north  the 
latter  can  everywhere  be  seen  to  lie  normally  on  the  sandstone,  with  little 
baking,  and  along  the  border  from  this  point  around  to  the  west  the  same 
conditions  hold  for  a  long  way  south,  until  one  comes  to  the  point  where 
the  wood  road  coming  up  from  the  reservoir  crosses  the  brook  and  goes  up 
onto  Mount  Tom,  and  where  the  posterior  ridge  itself  rises  to  its  greatest 
height  in  Little  Mountain.  At  this  point  the  face  of  the  core  is  finely 
exposed  for  study,  as  indicated  in  fig.  25.  The  trap  comes  up  from  the 
depths  with  but  a  small  portion  (30  feet)  of  its  width  exposed,  sending 
out  great  dikes  into  the  sandstone  north  and  south.  The  southern  dike, 
starting  with  a  width  of  8  feet,  was  followed  50  feet. 

North  of  the  core  a  small  dike  is  seen  inclosed  wholly  in  the  sandstone, 
and  a  wide  dike  branches  from  the  main  mass  and  can  be  followed  a  long 
way  north  before  it  is  concealed  by  the  talus.  At  the  surface  the  trap  flows 
out  over  the  sandstone,  greatly  indurating  it,  and  becomes  the  sheet  which 
we  have  followed  from  the  north  to  this  point.  The  whole  is  like  a  great 
toadstool;  the  stem  is  the  core  which  forms  Little  Mountain.  The  west- 
ern and  most  of  the  southern  part  of  the  "umbrella"  is  broken  off  by 
erosion ;  the  eastern  part  is  the  sheet  dipping  east  beneath  the  tuff. 

The  exposed  wall  of  trap  shown  on  the  left  in  the  figure  seems  to  be  a 


468  GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

portion  of  the  western  wall  of  the  plug,  just  grazed  by  the  Mount  Tom- 
Holyoke  fault,  and  from  its  point  of  contact  with  the  sandstone  on  the 
north  the  boundary  of  the  plug  seems  to  run  first  north  and  then  about 
east  beneath  the  continuous  area  of  trap.  The  southern  half  of  its  bound- 
ary can  be  much  more  closely  located. 

Continuing  south  from  the  south  contact  of  the  trap  which  forms  part 
of  the  core  and  the  sandstone  in  fig.  25  along  the  highest  portion  of  the 
bluff,  and  turning  round  the  face  of  the  high  bluff  at  its  south  end  where 
it  overlooks  the  reservoir,  one  finds  the  sandstone  to  be  only  a  thin  veneer- 
ing on  the  face  of  the  walls  of  the  great  throat,  and  one  can  dig  at  the 
surface  and  see  that  the  trap  extends  down  behind  the  sandstone.  The 
surface  boundary  of  trap  and  sandstone  is,  along  this  line,  almost  the 
boundary  of  the  core  also,  and  erosion  has  spared  little  of  the  western  half 
of  the  overflow.  This  boundary  skirts  the  eastern  vertical  face  of  the  bluff 
for  a  little  way  north,  and  as  this  bluff  soon  turns  to  face  south,  and  runs 
east  less  steep  and  elevated,  the  surface  boundary  of  trap  and  sandstone, 
turns  and  runs  parallel  with  it,  but  not  quite  so  near  the  edge  of  the  bluff, 
and  becomes  the  south  boundary  of  the  sheet  as  the  latter  extends  east  from 

the  plug. 

The  baking  of  the  sandstone  from  the  point  Avhere  the  plug  was  first 
reached  has  been  exceptionally  marked,  but  along  this  wall  it  is  more  intense 
than  anywhere  else  in  the  valley  and  can  be  clearly  perceived  12  to  15  feet 
from  the  trap.  Along  the  middle  of  this  south  wall,  which  continues  east 
from  the  plug,  near  the  top,  a  foot- wide  dike  of  trap  is  intruded  between  the 
nearly  horizontal  layers  of  the  sandstone  beneath  the  sheet.  It  is  unusually 
decomposed,  to  a  pistachio-green  porous  mass,  with  spheroidal  structure. 

About  20  feet  below  this  a  great  horizontal  dike  or  sill  starts,  just  at  the 
reentrant  angle  made  by  the  southward  projection  of  the  high  bluff — that  is, 
just  where  the  plug  ends  and  the  wall  of  sandstone  facing  south  begins  and 
seems  to  branch  off  from  the  main  trap  mass.  It  starts  with  a  width  of  2 
feet  and  runs  down  east,  widening  soon  to  12  feet,  and  continues  with  the 
bottom  concealed,  and  at  its  end  it  bends  up  suddenly,  with  the  sandstone 
on  its  back,  into  a  vertical  position.  It  is  exposed  about  150  feet  and  is  very 
fine-grained,  black,  and  horizontally  fissured  for  2  feet  at  surface,  and  is  an 
exceptionally  fresh,  ringing,  small-columnar  rock  in  the  center.  It  sends  two 
narrow  dikes,  an  inch  to  a  few  inches  wide,  up  into  the  overlying  sandstone. 


TUE  POSTERIOR  SHEET.  469 

These  pass  upward  in  fissures  for  about  a  foot  and  then  bend  the  unbroken 
layers  of  tlio  sandstone  above  into  an  arch,  forming  minute  laccoliths,  and 
clearly  indicating  that  the  sill  was  injected  under  strong  pressure. 

SILLS  INTEUDED  IN  THE   SANDSTONKS  BELOW  THE  POSTEEIOR  SHEET. 

Besides  the  dikes  and  sills  which  penetrate  the  sandstones  so  abundantly 
in  the  immediate  ^^cinity  of  the  Little  Mountain  core,  other  small  sills 
appear  immediately  beneath  the  posterior  sheet  at  so  great  a  distance  that 
they  can  not  be  brought  into  very  close  connection  with  the  core  itself. 

The  most  northern  of  these  is  N.  60°  W.  of  the  Smiths  Ferry  station 
and  about  6  feet  below  the  top  of  the  sandstone.  There  is  a  sill  2  feet  wide 
which  can  be  followed  20  feet,  and  2  feet  below  this  is  another  only  1  foot 
wide.     The  sandstone  has  strike  N.  40°  E.  and  dip  22°  E. 

About  a  mile  south  along  the  blufP,  at  a  point  S.  65°  W.  of  Smiths 
Ferry  and  west  of  the  marked  drumlin  which  conceals  the  tuff,  a  larger  sill 
appears,  10  feet  below  the  trap,  which  is  4  feet  wide  and  8  or  9  feet  long. 
The  sandstone  is  much  disturbed  beneath  it. 

Along  the  boundary  of  the  sheet  farther  south  no  other  sills  are  found 
in  the  sandstone  below  until  the  western  border  of  the  plug  is  reached  and 
the  very  abundant  dikes  and  sills  appear  around  its  western  and  southern 
side,  which  have  been  described  and  figured  above. 

There  is  a  turnstile  by  the  road,  and  steps  going  down  to  the  railroad, 
a  mile  and  a  half  below  Smiths  Ferry,  and  tlie  field  road  southwest  from 
here  leads  out  over  a  ridge  to  an  amphitheater,  now  called  Forest  Park, 
from  which  all  the  points  here  described  are  easily  identified.  The  ridge 
is  the  continuation  of  the  trap  sheet  soiithward.  The  beautiful  horizontal 
12-foot  sill  described  above  (p.  468)  is  in  the  north  wall  at  one's  right,  and  if 
one  crosses  the  basin  to  the  next  ridge  overlooking  the  reservoir,  and  west  of 
the  terminus  of  the  Electric  Road,  the  high  bluff  of  the  plug  projects  south 
toward  the  point  where  one  stands,  and  above  the  screes  of  trap  fragments 
the  sandstone  veneering  can  be  seen  abutting  against  the  trap  in  the  thick 
woods. 

Turning  south  from  the  east  end  of  the  12-foot  sill  mentioned  above, 
on  the  southeast  of  the  plug,  and  going  to  the  bottom  of  the  basin  near 
the  brook,  one  finds  a  place  where  the  sandstone  is  crushed  into  sharp  folds 
a  foot  or  two  across  and  baked  by  the  trap,  which  has  penetrated  it  irregu- 
larly, but  apparently  only  in  small  amount. 


470 


GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 


Along  the  eastern  margin  of  this  basin  the  outcrop  of  the  trap  sheet 
is  plainly  visible,  covered  by  tuff  and  marked  at  its  base  by  a  prominent 
talus.  As  it  is  followed  south  its  boundary  makes  a  great  loop  to  the  east, 
where  the  ridge  is  cut  through  by  a  brook,  but  rises  again  in  a  higher  l^luff 
south  of  the  brook,  now  marked  by  a  high  trestlework  lookout-tower.  The 
contact  on  the  sandstone  below  is  everywhere  normal — the  compact  trap 
rests  on  unbaked  sandstone — until  the  boundary  swings  aroiind  the  south 
end  of  this  prominent  hill  to  a  point  which  rises  sharply  in  a  bluff  30  rods 
north  of  where  Roaring  Brook  crosses  the  road.  This  is  the  brook  that 
comes  up  from  the  south  and  bends  sharply  to  enter  the  Connecticut 
southeast  of  Mount  Tom.  Delaney's  quarry,  described  below,  is  situated 
just  south  of  its  mouth,  between  the  road  and  the  railroad. 


0/u>/rswji>sron£  »„  "/^ 
ToserHEn. 


SANOSro/^^- 


AMyeoAio/o 


/    ^    J   /  >  ^  /  ^    '   ^  /    /    J    ^    /    /  -7- 


TiG.  26. — Section  of  Delaney's  quarry,  in  Northampton,  near  the  north  line  of  Holyoke,  on  the  Connecticut  Eiver  Railroad, 

The  base  of  the  trap  sheet  in  this  bluff  is  scoriaceous  and  filled  Avith 
sheets  and  filaments  of  limestone  and  shale  exactly  like  the  surface  of  the 
trap  a  few  rods  south  at  the  quarry  mentioned  above,  so  that  I  am  compelled 
to  assume  that  a  portion  of  the  surface  has  here  been  under-rolled  to  make 
the  base 

The  conditions  here  are  so  peculiar  that  they  require  detailed  discus- 
sion, which  may  best  begin  with  a  detailed  description  of  the  quarry  east 
of  the  fault,  returning  then  north  to  the  south  bluff  section,  which  can  be 
best  explained  by  a  comparison  with  the  conditions  at  the  quarry. 


DELANEYS  QUARRY,  NEAR  THE  NORTH  LINE  OF  HOLYOKE. 

This  is  a  good  example  of  a  deeply  submerged  lava  surface  onto  which 
much  mud  was  washed  while  it  was  still  plastic  (see  fig.  26).  Many  masses 
of  the  mud,  varying  from  thin  filaments  a  few  inches  long  and  a  small 


THE  POSTEKIOR  SHEET,  471 

fraction  of  an  int'li  thick  to  broad  layers,  were  washed  onto  the  trap  and 
sank  into  its  mass,  so  that  the  upper  3  or  4  feet  of  the  trap  is  kneaded  full 
of  the  dark,  compact  shales,  which  have  at  times  glazed  an<l  wrinkled  sur- 
faces, as  in  the  ordinary  shale,  especially  at  the  south  end  of  the  quarry, 
and  for  3  or  4  feet  the  trap  and  shale  are  kneaded  together;  shreds  and 
l)road  plates  of  the  dark-graj^,  thin-laminated  shale  are  twisted  and  plicated 
in  the  black  trap. 

In  sections  thin  tortuous  layers  of  the  shale  can  be  seen  in  the  trap,  at 
times  directly  inclosed  by  the  trap,  at  times  a  part  or  the  whole  of  a  film 
resting  in  the  bottom  of  a  steam  hole,  as  if  the  moisture  of  the  mud  liad 
furnished  the  steam  to  form  a  cavity  too  large  for  the  mud  to  fill.  The 
sandstone  above  wraps  over  the  very  irregular  surface  of  the  trap,  which 
rises  and  falls  20  feet  within  the  limits  of  the  cpiarry  and  dips  17°  E.  It 
fits  itself  also  around  smaller  irregularities  and  separate  blocks  of  the  trap, 
and  for  several  inches  it  is  very  ferruginous  and  contains  small,  fiat  con- 
cretionary grains  like  the  Clinton  iron  ore.  The  trap  is  fine-amygdaloidal 
for  12  feet  down  from  the  surface. 

A  north-south  fault  appears  in  the  quarry  with  an  upthrow  of  4  feet 
on  the  east,  dip  8°  E.,  and  many  strong  slickensides  appear  parallel  to  this 
surface.  In  pockets  along  this  zone  of  crushing  occur  datolite  crystals 
of  richer  color  and  more  brilliant  luster  than  any  found  elsewhere  in  the 
State.     They  are  described  in  the  Mineralogical  Appendix,  Chapter  XXII. 

There  were  opened  in  1892,  near  the  north  end  of  the  quarry  and  a  few 
feet  back  from  the  railroad  and  10  feet  above  its  level,  a  series  of  pockets 
in  the  solid  amygdaloidal  trap,  a  foot  or  more  below  its  surface,  which 
were  filled  with  the  finest  broad  lamellar  anhydrite,^  with  some  coarsely 
granular  calcite  near  the  borders.  These  pockets  were  small  and 
irregular,  never  more  than  3  inches  thick  and  4  inches  long.  Much 
very  coarsely  cleavable  calcite  appears  also  in  fissures  in  the  sandstone 
for  a  little  distance  above  the  trap,  inclosing  cavities  from  which  gyp- 
sum has  disappeared,  and  within  the  same  limits  broad  fissures  in  the 
sandstone  have  their  walls  coated  with  thick  ■  layers  of  specular  iron  in 
drusy  surfaces  of  fine  plates,  and  much  of  the  sandstone  is  cemented  by 
shining  scales  of  hematite.     The  sandstone  over  the  trap  has  alternating 

'This  is  a  most  unusual  occurrence  of  tlio  mineral.  It  occurs  rarely  in  the  Monte  Somma 
homhs.     R.  Brauns,  Neues  Jahrbuch  fiir  Min.,  1894,  p.  257.     See  Mineralogical  lexicon:  Bull.  126. 


472       GEOLOGY  OF  OLD  HAMPSHIEB  COUNTY,  MASS. 

layers  darkened  by  fine  tuffaceous  material.  Twelve  feet  above  the  trap 
the  coarse  tuff  begins  to  appear  in  the  sandstone,  and  this  is  its  most 
southern  occurrence. 

It  seems  to  me  probable  that  the  mud  was  swept  over  the  still  plastic 
trap  and  sank  into  it  to  make  the  streaks  of  sandstone,  and  that  the  trap 
was  thus  frothed  up  to  make  the  amygdaloidal  and  cavernous  structure.  The 
formation  of  the  calcite,  anhydrite,  gypsum,  and  hematite  all  took  place 
immediately  after,  under  the  influence  of  heated  solutions  from  the  still 
heated  trap.  The  pyrite  of  the  trap  furnished  the  sulphuric  acid  for  the 
anhydrite,  and  little  calcite  developed  in  the  heated  cavities  of  the  trap 
and  gypsum  and  much  calcite  in  the  cooler  fissures  in  the  sandstone,  while 
abundant  hematite  and  some  magnetite  impregnated  the  sands  and  formed 
the  beautiful  surfaces  of  specular  iron. 

In  the  bluff  section  to  the  north,  mentioned  on  page  470,  the  vertical 
south  wall  of  the  hill  shows  an  exactly  similar  amygdaloidal  band,  about 
12  feet  thick,  filled  with  wholly  similar  twisted  sheets  of  sandstone  and 
shale.  Indeed,  at  one  point  a  block  of  sandstone  at  least  3  feet  thick  and 
10  feet  long  is  half  included  in  the  trap  and  half  projecting.  It  is  twisted 
and  baked  gray  and  fissured  all  to  pieces  at  the  surface  nearest  the  trap, 
and  is  reddish  at  the  center.  This  porous  band  of  the  trap  is,  however, 
not,  as  in  the  quarry  just  south,  the  surface  layer,  but  forms  the  base  and 
is  covered  by  about  20  feet  of  coarsely  columnar  compact  trap  in  the  ver- 
tical wall,  and  the  thickness  of  the  whole  bed  upon  it  is  much  greater.  It 
can  be  seen  to  rest  upon  the  fine-grained  reddish  sandstone  below.  It  is 
very  porous,  especially  around  the  included  fragments,  and  this  porosity 
runs  out  gradually  in  the  compact  ti-ap  above.  One  must  put  emphasis 
upon  the  fact  that  these  are  thin  sheets  and  films  of  thin-bedded  shale, 
often  twisted  in  the  lava  and  presenting  shapes  which  can  not  possibly  be 
explained  as  inclusions  of  a  solidified  sandstone  torn  off  from  the  surface 
of  the  fissures  up  through  which  the  lava  passed. 

One  may  imagine  the  lava  flowing  southeast  from  the  great  vent  at 
Little  Mountain,  over  the  sand  flats  under  several  hundred  feet  of  water, 
for  the  most  part  cased  in  solid  lava  and  thus  producing  very  little  effect 
upon  the  ground  over  which  it  flowed  and  being  very  little  influenced  by 
the  water.  If,  however,  the  crust  were  locally  ruptured  and  the  liquid  lava 
came  in  large  quantity  into  contact  witli  the  water,  a  violent  uprush  of 


THE  POSTERIOR  SHEET.  473 

steam  and  water  niijilit  oeeur,  and  an  indraft  of  nmddy  water,  which  woukl 
suddenly  coat  the  surface  with  fine,  thhi-laminated  mud,  and  this  would 
then  be  mingled  with  tlie  ])lastic  lava  so  as  to  produce  veins  like  those  seen 
in  Castile  soap. 

The  current  was  here  passing  directly  into  the  apex  of  the  area  of  the 
Chicopee  shale,  and  the  fragments  in  the  trap  are  of  exactly  the  same  char- 
acter as  this  rock.  This  mixed  layer  appears  in  its  normal  position  on  the 
surface  of  the  trap  at  the  quarry,  and  the  heavy-bedded  sandstones  above 
show  that  they  were  very  rapidly  accumulated  over  the  still  heated  trap 
b}^  the  abundance  of  specular  iron  that  coats  all  their  fissures.  Here  in 
the  bluff  the  whole  former  surface  of  the  trap  is  under-rolled  and  appears 
inverted  upon  the  sandstone  of  the  old  sea  bottom. 

THE    EOAKING    BROOK    FAULT    AND    THE    DISAPPEARANCE    OF    THE    POSTERIOR 

SHEET. 

The  amygdaloidal  surface  of  the  trap,  so  well  exposed  at  Delaney's 
quarry,  can  be  followed  continuously  a  few  rods  north. in  the  bed  of  Roar- 
ing Brook.  It  is  here  more  coarsely  amygdaloidal  and  without  inclusions 
and  is  covered  by  a  thin  bed  of  tuffaceous  sandstone  full  of  fiat  fragments 
of  a  white  volcanic  rock  (see  p.  474).  Following  vip  the  brook  across  the 
road  to  a  small  waterfall  on  this  amygdaloidal  surface,  with  the  sandstone 
forming  the  bank,  one  comes  upon  the  first  fault.  At  the  foot  of  the  fall 
is  the  scoriaceous  surface.  The  trap  over  which  the  water  plunges  is  com- 
pact, and  here  there  is  a  fault  with  upthrow  on  the  west  which  amounts 
nearly  to  the  thickness  of  the  trap  sheet.  A  little  west  there  is  another 
fault  in  the  same  direction  and  throw,  running  about  N.  20°  E.,  parallel 
with  and  a  little  west  of  the  brook,  which  seems  to  have  given  the  brook 
its  direction,  and  which  continues  north  along  the  east  foot  of  the  eastern 
bluff  of  the  hill  30  rods  north  of  the  brook  that  contains  the  inverted 
section  described  above  (p.  472)  and  crosses  the  next  brook  on  the  north 
10  rods  west  of  the  road  and  of  the  broad  surface  covered  with  bird-tracks 
beside  the  road.  It  has  the  sandstone  on  the  east  and  the  tuff  and  trap  on 
the  west. 

As  the  surface  of  the  trap  sheet  is  exposed  in  the  bed  of  Roaring  Brook, 
and  as  the  base  of  the  same  sheet  appears  30  feet  higher  in  the  hill  30  rods 
north,  the  aggregate  throw  of  the  faults  is  about  60  feet. 


474       GEOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 

From  the  bend  in  the  brook  the  upper,  highly  scoriaceons  surface  of 
the  trap  can  be  followed  north,  along  east  of  the  fault  line  and  behind  the 
house  standing  north  of  the  brook.  The  trap  is  very  deeply  rotted.  It  is 
a  fine  example,  rare  in  this  region,  of  a  protected  pre-Glacial  surface.  It 
falls  apart  now  into  a  mass  of  spheroidal  bodies  made  up  of  many  very 
thin  concentric  layers,  a  result  of  rapid  cooling.  It  is  the  same  surface 
which  just  adjacent  is  loaded  with  shale. 

On  the  other  hand,  going  south  up  the  brook  from  its  bend,  one  finds 
it  running  on  the  trap  near  its  base  until  one  comes  to  its  farthest  outcrop 
near  the  Electric  Road.  Here  the  trap  rests  on  the  sandstone  irregularly, 
partly  upon  its  basset  edges  on  the  west  side  of  the  outcrop  and  partly 
mantling  over  to  rest  on  the  surface  of  the  upper  stratum  toward  the  east. 
The  fault  must  pass  just  to  the  west  of  this  contact. 

THE  BLENDING  OP  THE  TUFF  WITH  THE  SURFACE  OP  THE  POSTERIOR  BED. 

Beneath  the  northeastern  pavilion  in  Forest  Park  (fig.  25,  p.  466,  near 
the  east  end)  the  surface  of  the  posterior  bed  is  full  of  angular  fragments  of 
a  fine-grained  trap,  partly  compact  and  partly  porous,  which  are  plainly 
foreign  inclusions.  They  are,  however,  sometimes  fused  into  continuity 
with  the  inclosing  trap,  as  if  they  had  fallen  into  the  molten  lava  and 
had  been  themselves  partly  remelted.  The  inclosing  trap  has  a  mottled, 
red-brown,  weathered  surface,  and  is  covered  by  small  pimply  knobs, 
which  cause  the  mottled  appearance,  and  it  is  so  coarse-grained  that  the 
white  feldspars  can  be  easily  seen.  It  is  thus  quite  unlike  the  in(;losed  trap. 
The  old  surface  of  the  trap  sheet  is  filled  in  this  way  for  a  distance  of  150 
yards  west,  to  the  top  of  Little  Mountain,  and  600  yards  north.  This  is 
quite  the  same  thing  as  the  mingling  of  mud  with  the  surface  of  the  same 
sheet  just  south,  at  Delaney's  quarry,  as  described  on  page  470,  and  indi- 
cates that  the  ejected  fragments  fell  upon  the  surface  of  the  flowing  lava 
here  as  the  mud  spread  over  it  farther  south. 

A   TUFFACEOUS   SANDSTONE   CONTAINING   WHITE   TRAP. 

Tliis  curious  rock  appears  just  above  the  posterior  bed  on  the  north 
bank  of  Roaring  Brook,  a  few  rods  east  of  the  Northampton-Holyoke  road 
and  near  the  line  between  these  towns.  It  is  a  sandstone  containing  many 
small,  angular  pieces  of  a  white  rock  which  effervesce  freely  and  seem  to 
be  calcite.     They  prove  to  be  a  scoriaceous  lava,  now  filled  with  secondary 


THK  POSTElilOK  SHEET.  475 

calcite,  ill  which  the  muud  and  often  conHuent  sleain  holes  are  bounded  hy 
very  thin  walk,  which  appear  as  black  lines  surrounding  the  calcite  filling-s 
and  contain  only  twinned  plagioclase  rods.  The  sandstone  also  contains 
crackled  fragments  of  bottle-green  glass  in  whicli  rodlike  crystals  of  plagio- 
clase of  two  sizes  appear.  The  fi-agments  are  thus  like  the  white  trap  found 
a  mile  farther  north,  on  the  brook  north  of  the  station  of  the  Mount  Tom 
Railroad  (see  p.  365). 

THE   POSTEBIOR   DIKE   ACROSS   HAMPTON    COUNTY. 

One  can  trace  the  trap  for  a  short  distance  farther  south,  hardly  to  the 
town  line,  as  everything  is  heavily  covered  with  alluvium.  The  bed  then 
disappears  and  seems  to  be  concealed  for  nearly  3  miles  by  the  throw  of 
the  Holyoke  fault.  It  reappears  again  on  the  road  from  Holyoke  to 
Wright's  pond,  with  a  thickness  of  33  feet,  and  can  thence  be  traced  south- 
ward to  the  excellent  section  made  by  the  Holyoke  and  Westfield  Railroad, 
where  it  is  120  feet  thick  and  divided  into  two  beds.  The  lower  of  these 
(resting  on  the  fine  red  sandstone,  dipping  15°  W.,  and  not  perceptibly 
altering  it)  is  53  feet  thick,  very  coarse-columnar  in  its  main  mass,  with  8 
to  10  feet  amygdaloidal  above,  while  the  up)per  bed  rests  directly  upon  the 
lower  one  and  is  amygdaloidal  at  its  surface  for  15  feet  in  thickness,  and 
the  whole  is  covered  by  a  fine-grained  red  sandstone. 

This  thinning  out  toward  the  north  may  indicate  that  the  bed  is  not 
continuous  across  the  covered  area;  on  the  other  hand,  the  double  character 
of  the  bed  is  repeated  as  in  the  bed  to  the  north.  South  from  the  }-ailroad 
crossing  the  bed  appears  as  a  continuous  ridge,  increasing  in  altitude  until 
it  reaches  the  Boston  and  Albany  Railroad,  where  another  fine  section  is 
exposed  east  of  the  Tatham  station,  which  repeats  almost  exactly  the  rail- 
road section  described  above. 

Here  gray  and  red  shaly  sandstones  dip  25°  E.  beneath  the  trap,  and 
are  distinctly  baked  for  2  feet  and  show  a  rust-filled  columnar  parting. 

The  lower  bed  is  32  feet  thick,  with  about  10  feet  finely  amygdaloidal 
above  and  full  of  diabantite  and  calcite.  The  upper  bed  is  massive  and  44 
feet  is  exposed.  In  it  ai-e  four  zones  of  crushing,  1  to  2  feet  wide,  with  strike 
N.  10°  E.,  dip  70-80°  W.,  which  indicate  small  faults  of  unknoAvn  throw. 

Just  above  the  mouth  of  the  first  brook  entering  Westfield  River  from 
the  south,  east  of  Provens  Mountain,  in  Agawam,  a  massive  ledge  of  the  trap 
projects  into  the  main  stream,  and  the  brook  runs  over  the  trap  in  a  pretty 


476  GEOLOGY  OP  OLD  HAMPSHIRE  COUNTY,  MASS. 

waterfall  where  it  crosses  the  road  at  J.  Miller's  house.  This  is  directly 
in  prolongation  of  the  ridge  north  of  the  river,  and  there  is  no  indication  of 
any  fault  between  these  points.  The  bed  is  then  lacking  for  2  miles  south 
because  of  the  throw  of  the  State-line  fault,  ^  but  reappears  again  at  the 
house  of  A.  Flower,  and  then  follows  the  road  closely  S.  10°  W.  to  the 
State  line  and  on  across  Suffield  in  Connecticut.  It  rises  as  a  low  ridge 
above  the  sands,  which  conceal  the  contacts.  The  greatest  thickness  exposed 
was  62  feet. 

THE  TALCOTT  SHEET. 

This  is  the  anterior  sheet  of  Percival.  It  enters  the  Grranville  quad- 
rangle at  its  southeast  corner,  in  the  town  of  Suffield,  Connecticut,  and 
therefore  appears  on  the  map,  but  it  does  not  cross  the  State  line. 

THE  TUPF  AISTD   TUFFACEOUS  AGGLOMERATES. 

THE    DEEKFIELD    BED. 

At  the  first  outcrop  on  the  Greenfield-Turners  Falls  road  the  rock  is  a 
complete  "schalstein,"  a  thin-bedded,  dark -green  rock,  largely  decomposed 
into  a  flaky  chlorite,  and  abounding  in  grains  of  calcite  and  a  reddish 
zeolite  for  the  most  part  iron-stained  prehnite.  This  bed  seem  to  rest 
directly  upon  the  trap  and  to  have  but  limited  extent. 

THE    GRANBY    BED. 

The  coarse  arkoBe  or  sandstonesj  consisting  of  slightly  waterwom  and 
soi'ted  granitic  materials,  which  dip  beneath  the  great  bed  of  diabase  of  the 
Holyoke  range,  are  followed  above  the  diabase  by  exactly  similar  beds  of 
pale-buff  .arkose  containing  little  iron  and  having  a  low  dip  south  from  the 
Mount  Holyoke  range  and  southeast  to  east  from  the  Mount  Tom  range. 

This  is  followed  by  heavy  beds  of  black  tuff  and  tuffaceous  sandstone, 
which  vary  from  fine-grained  volcanic  sandstones  to  coarse  breccias  and 
agglomerates,  and  from  rocks  made  up  wholly  of  volcanic  ddbris  to  such  as 
contain  fragments  of  granitic  and  gneissoid  rocks,  or  in  the  finer-grained 
varieties  contain  the  materials  of  granite,  especially  white  mica  on  the 
lamination  faces  and  grains  of  quartz  in  the  mass  of  the  rock.  In  other 
eases  rounded  masses  of  diabase  are  distantly  scattered  in  deep-red  sandstone- 

This  band  begins  opposite  the  east  end  of  the  diabase  bed  and  half  a 
mile  south  of  it,  and,  attaining  a  surface  width  of  1,600  feet,  runs  west 

'  See  pp.  370,  450. 


THE  GUANBY  TUFF  BED.  477 

parallel  to  the  diabase  to  and  across  the  Connecticut,  and  continues  south 
parallel  to  the  Mount  Tom  range  to  within  a  short  distance  of  the  Holyoke 
town  line. 

It  appears  first  in  the  blufip  overlooking  the  northern  of  the  Belcher- 
town  ponds  as  a  thin-bedded,  rusty  sandstone  with  grains  of  diabase.  It 
strikes  N.  G0°  W.  and  dips  west  into  the  hill  and  beneath  the  sandstone, 
and  has  plainly  been  faulted  into  its  present  position,  and  received  thus 
its  unusual  westward  dip.     It  is  wholly  separated  from  the  remainder  of 

the  bed. 

Farther  west,  where  the  Bay  road  after  crossing  the  diabase  goes  south 
toward  Belchertown,  the  tuff  does  not  outcrop,  but  in  the  fields  west  of  this 
road  abundant  fragments  occur  by  which  it  can  be  approximately  traced, 
and  soon  it  appears  in  a  strong  ridge  which  can  be  followed  west  to  the  next 
road.  Here  the  tuff  appears  for  a  long  distance  north  and  south  of  the  second 
house  met  after  going  south  across  the  mountain  into  Granby  (the  house 
formerly  occupied  by  A.  Convere,  now  in  ruins),  and  tracing  it  west  it  runs 
just  south  of  a  small  diabase  mass  southwest  of  this  house.  It  is  an  arkose 
containing  in  great  number  angular  diabase  fragments,  some  as  large  as  a 
pea,  and  is  cut  off  by  a  fault,  which  can  be  traced  very  clearly  in  the  woods 
south  of  the  diabase.  Farther  west  it  has  been  crossed  at  several  points  but 
not  followed  continuously  through  the  densely  wooded  area  to  the  next  road, 
i.  6.,  the  main  or  Notch  road,  and  it  appears  at  the  first  branching  of  this 
road  south  of  The  Notch.  The  rounded  rusty  hummocks  of  the  tuff  are 
very  conspicuous. 

The  rock  is  composed  mainly  of  trap  in  small  angular  fragments  which 
look  like  pitchstone  and  which  consist  of  a  diabase  with  semicrystalline  base. 

The  tuff  bed  makes  a  small  angle  with  the  road  running  east  from  this 
point,  and  its  exposures  are  found  abundantly  in  the  roadside  imtil  the  road 
goes  down  onto  the  terrace  sands.  The  outcrops  of  the  tuff  vary  from  deep- 
brown,  thin-bedded  sandstones,  which  the  microscope  shows  to  be  quartz 
sandstones  impregnated  with  the  finest  dust  of  the  trap,  to  agglomerates 
in  which  masses  of  trap  a  foot  across  appear,  as  in  the  woods  just  south  of 
where  the  ninth  volcanic  core  (see  p.  483)  crosses  the  road. 

Farther  east  the  tuff  bed  is  cut  off  completely  by  the  ninth  core.  The 
best  exposures  are  where  the  bed  is  crossed  by  the  wood  road  which  runs 
north  from  Moody  Corners,  where  the  rusty  tuff  weathers  into  a  pile  of 


478       GEOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 

large  spheres,  and  in  tlie  brown  ledges  visible  from  this  road  off  to  the 
south,  whose  ragged  mass  is  made  up  of  large  angular  pieces  of  the  trap 
cemented  by  finer  dust  of  the  same  material. 

Here,  in  the  north  of  South  Hadley,  the  bed  has  great  width,  and  across 
to  the  north,  at  the  top  of  the  fine  cliffs  of  buff  sandstone  which  overhang 
the  entrance  to  the  brook  gorge  reached  by  H.  White's  wood  road,  just  east 
of  the  school  and  at  the  highest  point  of  the  ridge,  the  base  of  the  tuff  and 
its  junction  with  the  undei'lying  sandstone  is  instructively  shown.  In  a 
vertical  wall  of  the  pale-buff  sandstone  the  lower  half  is  composed  of  the 
usual  coarse  granitic  sand,  and  above  a  large  number  of  angular  masses  of 
the  trap,  of  the  size  of  one's  fist  and  larger,  are  scattered  at  some  distance 
from  one  another  in  the  same  buff  sandstone,  while  a  few  feet  higher  up 
the  rock  is  deep  rusty-brown  tuff. 

These  fragments  are  manifestly  the  first  and  farthest-thrown  products 
of  a  distant  explosion,  as  the  perfectly  classified  material  of  the  sandstone 
below  and  around  the  fragments  indicates  a  current  capable  onlj-  of  moving- 
coarse  sand  before  and  during  the  time  when  these  large  angular  masses 
were  dropped  here,  to  be  followed  by  so  great  a  supply  of  trap  d(^bris  that 
the  granitic  sand  almost  disappears  in  it. 

Still  farther  west,  where  the  bed  runs  to  a  point  on  the  south  of  the 
Black  Rock  dike,  it  is  a  loosely  cemented,  mass  of  trap  grains,  all  of  the 
size  of  large  peas.  From  this  point  west  to  the  Comiecticut  it  is  replaced 
by  the  Black  Rock  dike,  and  on  the  west  of  the  river  it  apjDears  in  the 
cutting  south  of  the  point  where  the  road  crosses  the  railroad,  below  Mount 
Tom  station  (Lymans  Crossing),  as  a  coarse  trap  agglomerate  resting 
directly  on  the  trap,  and  except  where  it  is  interrupted  by  the  leather-mill 
fault  it  appears  in  the  roadside  all  the  way  to  the  Holyoke  line.  The 
blocks  are  a  foot  across,  and  in  the  fine-grained  matrix  a  great  number  of 
graphite  scales  occur. 

Just  south  of  the  cemetery  north  of  Smiths  Ferry,  by  the  roadside,  the 
great  blocks  of  the  trap,  nearly  2  feet  long,  cemented  by  the  finer  frag- 
ments of  the  same  material,  can  be  seen  to  rest  directly  upon  the  surface  of 
the  coarse  rusty  sandstone,  and  to  have  sunk  into  its  upper  surface  as  they 
fell.  Very  little  foreign  material  can  be  found  here  in  the  finer  portion  of 
the  tuff,  but  it  seems  never  wholly  wanting,  and  the  graphite  and  muscovite 
scales  are  never  absent. 


THE  GKANBY  TUFF  BED.  479 

Fartlu'v  south  fine  fresh  exposures  can  be  studied  where  the  road  and 
raih'oad  come  nearest  together,  and  liere  tlie  round  blocks  are  a  foot  in 
diameter.  All  along  the  distance  we  have  traced,  tlie  tuff  is  in  great  thick- 
ness, and  occupies  the  whole  distance  between  the  posterior  ti-ap  range  and 
the  ton-ace  sands  adjoining  the  river,  its  varying  width  of  outcrop  depend- 
ing upon  the  heiglit  to  which  it  overhangs  the  ti-ap.  It  is  well  exposed  by 
the  cuttings  of  the  railroad. 

The  first  reefs  of  sandstone  containing  foot-tracks  appearing  in  the  river 
are  brought  up  by  a  fault  running  N.  25°  E.  (see  p.  473),  which  cuts  off 
the  tuff,  and  south  of  this  line  where  it  appears  in  the  quarry  by  the  rail- 
road; near  the  Holyoke  line  the  tuff  has  dwindled  quite  suddenly  to  three 
beds  with  a  thickness  of  less  than  3  feet  each,  included  in  the  deep-red, 
fine  sandstone,  and  lying  3  to  4  feet  apart,  the  lowest  layer  10  feet  above 
the  in-egular  surface  of  the  trap,  that  thickness  of  sandstone  having  suddenly 
intervened. 

President  Hitchcock's  descriptions  of  the  tuff  beds  are  full  and  clear.^ 
The  several  repetitions  of  the  bed  given  by  him  south  of  Mount  Holyoke 
are  due  to  faulting.  The  occurrence  in  West  Springfield  and  the  occur- 
rences mentioned  at  the  base  of  the  main  trap  and  on  its  sin-face,  and  the 
varieties  described  as  "masses  of  red  and  gray  sandstone  embedded  in  a 
scoriaceous  paste,"  are  separately  discussed  on  pages  453-460  and  476  as 
cases  of  the  inclusion  of  sedimentary  material  at  the  surface  or  base  of  the 
flowing  sheets  of  trap. 

THE    ISOLATED    MASS    OF    TUFF    NORTH    OF    THE    SEVENTH    CORE. 

A  half  mile  north  of  the  seventh  core,  described  in  the  next  section 
(p.  482),  and  a  little  more  than  a  mile  north  of  J.  McGrath's  house  and 
reached  by  a  wood  road  from  this  house,  in  the  deep  woods  in  the  north  part 
of  Granby,  is  a  great  isolated  mass  of  the  coarse  rusty  diabase-sandstone, 
which  stands  perhaps  12  feet  high  and  rises  like  a  great  telescope  upon  a 
massive  pedestal.  The  mass  does  not  seem  to  be  more  than  a  rod  square 
beneath  the  surface,  and  must  harve  been  dropped  into  the  sandstones  here 
by  a  fault,  of  which  in  the  covered  and  heavily  wooded  region  no  other 
trace  can  be  found.  It  shows  that  the  tuff  extended  half  a  mile  north  of  its 
present  outcrop. 


'18W,  Explanation  of  Geological  Map;  1848,  Am.  Jour.  Sci.,  2d  series,  Vol.  IV,  p.  199. 


480  GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

SOURCE    OF    THE    MATERIAL    OF    THE    TUFF    BED. 

The  sections  of  the  diabase  from  the  tuff  show  varieties  containing  (1) 
much  glass  base,  (2)  well-developed  porphyritic  augites  and  olivines,  (3) 
development  of  augite  as  early  as  the  oldest  feldspars,  (4)  inclusions  of 
quartz  grains,  all  peculiarities  common  in  the  newer  dikes  and  not  found 
in  the  older  diabase  of  the  Mount  Holyoke  bed.  The  newer  dikes  lie 
along  the  same  line  with  the  tuff,  and  are  punched  up  through  it. 

The  description  of  the  base  of  the  bed  given  above  indicates  that  an 
explosive  eruption  of  diabase  occurred  somewhere  along  this  line,  which 
furnished  the  great  mass  of  material  whose  length  of  outcrop  is  10  miles 
and  whose  thickness  is  about  550  feet.  The  later  dikes  seem  to  have  been 
driven  up  through  this  tuff  bed,  and,  I  think,  lie  along  the  line  of  the 
great  fissure  up  through  which  the  diabase  of  the  Holyoke-Mount  Tom 
bed  comes. 

It  is  just  south  of  the  ruined  stone  mill  above  Smiths  Ferry  that  the 
tuff  bed  is  thickest  and  the  blocks  in  it  are  largest,  and  it  contains  many 
fragments  1  to  3  feet  across.  Their  size  diminishes  southward;  1  mile  south 
(R.  Houston's)  the  fragments  reach  8  inches;  at  2  miles  (P.  Brenn's)  4  inches, 
and  here  the  tuff  has  dwindled  to  three  beds  3  feet  thick,  and  the  mass  of 
the  fragments  are.  about  an  inch  long,  though  above  the  upper  bed  distant 
rounded  fragments  5  to  6  inches  long  appear  in  the  sandstone.  The  place  of 
eruption  seems  to  have  been  somewhat,  but  not  far,  north  of  Smiths  Ferry. 
It  is  interesting  to  trace  the  graphite  found  in  the  tuff  and  in  the  sandstone 
above  it  to  its  source,  which  must  have  been  in  the  region  of  Sturbridge,  18 
miles  to  the  east,  while  the  crystalline  boundary  on  the  west  is  only  9  miles. 

HOLLOW  BOMB  FROM  DELANEY'S  QUARRY,  NORTHAMPTON. 

I  dislodged  from  the  tuff  at  this  qxiarry  a  rounded  bomb  If  by  1  by  1 
inch,  with  its  center  coarsely  amygdaloidal,  the  cavities  of  such  shape  that 
they  could  have  been  formed  only  by  steam  and  not  by  later  weathering, 
and  a  border  from  ^  to  J  inch  wide  which  was  completely  compact. 

PETROGRAPHICAL    DESCRIPTION. 

The  rock  from  large  blocks  in  tuff  from  roadside  south  of  Smiths 
Ferry,  where  the  railroad  makes  a  deep  cut  in  the  tuff,  is  a  typical  diabase 
with  decomposed  feldspars;  a  brown  glass,  generally  devitrified  and  filled 


THE  NEWER  COKES  AND  SHORT  DIKES.  481 

with  l)l;ick  dust,  occupies  the  interstices.  Large,  fresh,  porphyritic  augites 
ajjpear,  which  are  often  twinned;  and  small,  very  brightly  polarizing  grains 
seem  to  be  olivine. 

THE  laaWER  SERIES   OF  CORES  AND  SHORT  DIKES. 

BELCHERTOWN. 
THE   FIRST   VOLCANIC   CORE. 

This  is  situated  about  150  rods  southeast  of  the  east  end  of  the  Holyoke 
main  sheet  of  trap  and  2,100  feet  N.  47°  E.  of  the  house  of  H.  Moody,  on 
the  Bay  road  in  Belchertown.  It  is  just  south  of  the  source  of  a  brook  and 
within  the  edge  of  the  woods,  rising  in  a  small  knoll.  On  the  north  edge  the 
contact  with  the  sandstone  is  well  seen,  and  the  baking  of  the  latter  is 
unusually  severe.  The  alteration  has  hardly  begun  to  decrease  in  the  width 
exposed — above  10  feet.  The  coarse  red  sandstone  is  baked  into  a  hard, 
light-gray  graywacke,  its  mica  and  feldspar  grains  having  been  so  affected 
by  the  heat  that  they  have  been  removed  by  later  infiltration,  leaving  pores 
coated  with  rust.  Still  nearer  the  contact  the  sandstone  contains  many  white 
compact  masses,  which  are  in  part  hollow  tubes  and  seem  to  be  bones  of  a 
reptile  of  about  the  same  size  as  that  found  in  the  sandstone  at  Springfield. 
The  rock  is  here  rendered  hard  and  impervious,  and  this  has  favored  the 
preservation  of  the  bones.     The  specimens  contain  lime  phosphate. 

The  trap  is  fresh,  very  fine-grained,  and  shows  few  steam  pores.  Very 
thin,  well-formed  plagioclase  crystals,  flattened  parallel  to  oo  P  o6  ,  and  of 
the  earlier  and  larger  generation,  are  visible  with  the  lens. 

THE   SECOND   CORE. 

The  second  of  the  series  of  old  craters  or  volcanic  throats  is  exposed 
in  a  row  of  low  knolls  in  the  field  opposite  the  house  of  J.  A.  Barrett, 
where  the  Bay  road  has  just  crossed  the  mountain  toward  Belchertown 
village  and  near  the  western  line  of  the  same  township.  The  exposure  is 
only  about  15  rods  long  by  3  rods  wide,  with  strike  N.  60°  E.,  and  near  at 
hand  on  all  sides  are  abundant  outcrops  of  conglomerate,  which  proves  it 
to  be  an  isolated  deposit  of  limited  extent.  It  agrees  in  all  essentials  with 
the  rock  of  the  newer  intrusive  dikes. 

MON  XXIX 31 


482  GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 


THE   THIRD   COKE. 


This  rises  as  a  low  knoll  in  the  open  field  80  rods  S.  70°  W.  of  J.  A. 
Barrett's  and  10  rods  north  of  a  bluff  of  tuff.  It  is  exposed  with  a  width  of 
3  rods  and  a  length  of  5  rods.     Its  strike  is  N.  60°  E. 


GRANBY. 
THE  FOURTH   CORE. 


"Where  the  Amherst-Granby  road  passes  over  the  range  a  single  house 
(C.  Harris's)  stands  on  the  west  side.  Eighty  rods  S.  65°  E.  of  this  house, 
on  a  wood  road  at  the  south  foot  of  a  high  conglomerate  bluff,  is  a  small, 
nearly  circular  outcrop  of  trap  with  the  adjoining  sandstone  exceptionally 
altered  on  the  contact.  The  coaly  plant  remains  which  it  contains  are 
largely  changed  into  graphite. 

THE   FIFTH   CORE. 

In  the  field  west  of  the  only  other  house  on  this  road  (A.  Convere's) 
and  about  30  rods  N.  10°  W.  of  the  house  is  a  ridge  of  the  trap  8  rods 
wide,  25  rods  long,  running  N.  50°  E.  a  few  rods  north  of  the  tuff  bed. 

THE   SIXTH   CORE. 

In  the  same  field  with  the  last  and  about  35  rods  S.  75°  W.  from  it  is 
another  high  ridge,  14  rods  wide  and  30  rods  long,  having  about  the  same 
direction  of  its  longer  axis,  the  same  relation  to  the  tuff  bed,  and  the  same 
fine-grained,  dark-gray  diabase  without  amygdaloid  as  have  the  other  occur- 
rences. Like  them  all,  it  bakes  the  sandstone  strongly  and  seems  to  be 
wholly  surrounded  by  the  sandstone.  It  is  more  jointed  and  weathered 
than  usual.  About  5  rods  southeast  is  a  dike  of  the  diabase  10  feet  wide 
and  about  5  rods  long,  which  runs  north  and  south  parallel  with  a  fault 
plane  a  little  farther  east.  This  is  very  probably  an  offshoot  from  the 
latter  throat,  but  the  junction  is  covered. 

THE   SEVENTH   CORE. 

About  200  rods  north  of  J.  McGrath's  this  plug  occurs,  at  the  eastern 
terminus  of  the  band  of  diabase-tuff  which  crosses  the  Notch  road  and 
enters  Granby  from  the  west.  This  terminus  is  caused  by  the  intersec- 
tion of  the  tuff  band  by  one  of  the  main  north-south  faults  which  cross 
the  trap  ridge,  and  the  small  plug  of  trap  came  up  just  at  this  crossing.     It 


THl']  NEWER  CORES  AND  SHORT  DIKES.  483 

is  only  5  or  (J  rods  in  cross-section.  The  rock  is  black,  fresh,  compact,  only 
the  larger  and  earlier  generation  of  feldspars  showing  as  fine  lines  with  a 
stron"-  lens.  The  few  small  cavities  show  a  white,  compact,  fibrous  zeolite. 
Under  the  microscope  the  rock  shows  the  usual  structure,  with. the 
following  ])eeuliarities:  The  area  surrounding  the  cavities  is  of  much  finer 
"•rain  than  the  remainder.  The  large  feldspars  are  almost  always  made  up 
of  only  two  broad  individuals.  An  interstitial  groundmass  exists  in  consid- 
erable quantity  and  decomposes  to  a  red-brown  mass.  The  cavities  con- 
tain (1)  calcite,  (2)  diabantite,  (3)  wavy  interstratifications  of  diabantite  and 
natrolite,  (4)  natrolite,  (5)  a  red  decomposition  product  of  diabantite.  The 
whole  slide  is  full  of  the  finest  feathery  groups  of  magnetite  octahedra. 

THE   EIGHTH   OORE. 

One  will  find  this  large  and  interesting  mass  by  starting  from  the 
southern  boundary  of  the  tuff,  just  across  the  brook  south  of  the  first 
branching  of  the  road  after  passing  The  Notch.  The  sandstone  rises  in  a 
low  bluff  facing  north,  and  may  be  followed  due  east  100  rods  across  the 
field  and  through  the  woods  to  a  deep,  dry  gorge  running  north.  Follow- 
ing this  up  across  the  tuff,  one  comes  upon  the  trap  at  the  head  of  the  gorge 
and  can  follow  the  line  of  contact  very  closely  round  in  a  great  circle  to 
the  point  of  starting,  and  it  is  plain  in  several  places  that  the  trap  has  come 
up  through  the  sandstone  and  is  not  a  bed  in  it,  and  that  it  has  come  up 
on  the  line  between  the  sandstone  and  the  tuff,  intruding  partly  on  the 
area  of  the  one  and  partly  on  that  of  the  other.  No  amygdaloid  was 
observed,  and  the  diabase  is  very  fresh,  dark-gray  with  shade  of  brown, 
fine-grained,  the  earlier  generation  of  feldspars  being  just  visible  to  the 
eye,  and  then  striation  discernible  with  a  strong  lens. 

The  induration  of  the  tuff  was  very  marked  on  its  contact  with  the 
diabase  on  the  south  side  of  the  block.  This  would  be  the  upper  surface  of 
the  bed  if  it  had  been  a  contemporaneous  flow,  and  in  this  case  there  would 
have  been  no  trace  of  baking  of  the  adjacent  tuff. 

SOUTH  HADLEY. 
THE  NINTH   OOEE;    DIABASE   WITH   GRANITIC   INCLUSIONS. 

An  inspection  of  the  map  will  show  the  next,  or  Black  Rock,  core  to 
consist  of  a  great  rounded  mass  which  is  situated  south  of  the  Holyoke 
House  and  sends  off  to  the  east  a  long  tail-like  dike.     If  this  be  followed 


484       GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

east  half  a  mile  to  a  point  beyond  the  Moody  Corners  wood  road  it  will  be 
seen  to  be  bordered  on  the  south  by  a  rounded  mass  of  diabase  lithologically 
different  from  anything"  found  elsewhere  in  the  valley,  and  very  peculiar.  It 
has  along  dike  projecting-  to  the  east,  and  is  thus  paddle-shaped  and  rudely 
resembles  the  much  larger  Black  Rock  core.  It  is  an  aphanitic  diabase, 
which  is  full  of  grains  of  quartz,  microcline,  orthoclase,  etc. — so  full  that  in 
breaking  hand  specimens  from  every  ledge  across  its  width,  650  feet,  not 
one  was  found  that  did  not  contain  many  grains.  It  is  as  if  the  lava  had 
broken  up  through  unconsolidated  sandstones  or  flowed  over  beds  of  sand, 
taking  up  a  great  quantity  of  the  latter  in  its  progress ;  and  as  the  tuffs  con- 
tain a  ceiiain  quantity  of  the  same  granitic  sand,  and  as  this  had  often  been 
relied  on  as  a  means  of  distinguishing  the  tuff  from  weathered  outcrops  of 
the  trap  in  the  field,  a  new  difficulty  was  added,  and  weathered  outcrops 
of  this  trap  were  with  great  difficulty  distinguished.  Indeed,  in  my  first  sec- 
tion across  this  area  I  was  in  great  perplexity,  and  the .  peculiar  pitchstone- 
like  appearance  of  the  rock,  quite  new  in  this  region,  added  thereto.  Still,  I 
decided  before  cutting  sections  that  the  rock  must  be  a  lava  and  not  a  tuff. 

PETKOGRAPHICAL  DESCRIPTION. 

The  specimens  described  here  were  taken  on  a  section  through  the 
middle  of  the  dike,  where  a  wood  road  goes  north  a  short  distance  east  of 
Moody  Corners  and  crosses  the  brook  where  a  branch  enters  it.  From  this 
point  the  first  outcrop  of  the  trap  is  visible,  and  going  north  across  a  cleared 
area  and  then  a  short  distance  through  the  woods  to  a  second  cleared  field 
one  finds  abundant  exposm-es  of  the  trap,  and  to  the  north  long  ridges  of 
the  sandstone  appear.  The  first  section  was  taken  from  the  north  cleared 
field,  23  feet  south  of  north  border  of  the  diabase.  It  is  a  clear,  black, 
aphanitic  rock  of  unusual  freshness  and  slightly  pitchy  luster,  and  contains 
in  great  quantity  inclusions  of  granitic  quartz,  and  rarely  orthoclase,  of  the 
same  size  as  the  grains  in  the  adjacent  sandstone  (up  to  5™™).  As  many  as 
three  or  four  to  a  square  centimeter  occur,  and  the  lens  shows  many  more  of 
smaller  size.  Fragments  of  a  glassy  triclinic  feldspar,  perfectly  fresh,  and 
the  larger  groups  of  plagioclase  of  earlier  consolidation  are  also  visible. 
The  quartz  is  colorless  or  slightly  blue,  of  strong  greasy  luster,  without 
fissures  and  with  rounded  outline,  or  much  fissured  and  then  yellowish. 
A  single  grain,  5"™  square,  was  made  up  mostly  of  a  flesh-colored  feld- 
spar, but  nearly  a  quarter  of  its  mass  was  of  the  same  greasy,  bluish  quartz. 


THE  NEWER  COKES  AND  SHOET  DIKES.  485 

A  plate  of  the  feldspar  was  isolated  and  gave  the  optical  characters  of  ortho- 
clase  and  was  wholly  nntwinned. 

Tlie  pocket  lens  shows  grains  and  flat  vein-like  accumulations  of  a 
deep-red,  resin-like  character. 

The  microscope  reveals  anorthite,  labradorite,  augite,  fayalite,  mag- 
netite, liematite,  and,  as  inclusions,  quartz,  orthoclase,  microcline,  albite, 
rutile,  muscovite,  and  biotite,  and  fragments  of  granite  and  amphibolite. 
The  texture  of  the  rock  is  entirely  unlike  any  other  occurrence  among  the 
eruptives  of  the  region.  The  original  minerals  enumerated  appear  as  fresh 
as  in  a  modern  lava,  distantly,  often  very  distantly,  scattered  in  a  finely 
granular  ground. 

Anorthite. — The  porphyritic  feldspars  of  the  first  consolidation  are  often 
as  much  as  2°""  across.  They  seem  to  me  to  have  shot  out  rapidly  in  thin 
plates,  which  are  often  much  bent  and  broken  and  the  parts  moved  away 
from  each  other,  showing  what  is  otherwise  proved  below,  that  they  were 
formed  in  the  liquid  magma  and  moved  some  distance  in  it  before  its  entire 
consolidation.  They  are  of  glassy  clearness,  and  show  not  the  faintest 
trace  of  alteration.  They  are  bounded  by  perfectly  smooth  crystal  faces, 
except  where  deep  angular  or  rounded  offshoots  of  the  groundmass  extend 
into  them.  Inclusions  of  this  groundmass  are  very  abundant  and  variously 
arranged — at  times  collected  in  the  center,  at  times  in  concentric  lines 
marking  old  surfaces  of  the  crystal,  which  often  differ  from  the  final  form; 
at  times  quite  regularly  arranged  in  I,  T,  and  L  shaped  masses,  conforming 
to  the  cleavage  planes  with  great  regularity,  the  masses  being  of  quite  uni- 
form size.  The  crystals  show  lines  of  growth  of  great  delicacy,  which  are 
curiously  distm-bed  as  they  bend  in  to  surround  rounded  projections  of  the 
groundmass  which  penetrate  the  crystal.  Some  of  the  broadest  plates  lie 
so  that  they  show  no  twinning,  indicating  that  they  are  broad  by  the  large 
development  qoPcxi.  The  angle  of  extinction  is  —36°  on  either  side  the 
twinning  plane,  indicating  anorthite. 

Labradorite. — The  feldspars  of  later  consolidation,  from  J™""  to  the 
smallest  dimensions,  extinguish  with  an  angle  of  12J°  on  either  side  the 
twinning  plane,  and  so  are  very  probably  labradorite.  They  affect  the  lath 
shape  more  than  the  anorthite  does.  The  larger  are,  however,  broad, 
with  square  ends;  the  smaller,  nan'ow  rods;  and  they  are  rarely  in  contact, 
so  that  the  ophitic  structure  characteristic  of  the  common  diabase  is  wanting. 


486  GEOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 

The  augite  is  also  perfectly  fresh,  although  the  abundant  inclusions, 
combined  with  the  irregular  cleavage,  make  it  only  imperfectly  transparent. 
Separate  crystals  are  bounded  by  perfect  planes.  An  acute  pyramid  or 
dome  appears  with  especial  frequency.  They  are  finely  twinned,  with  the 
interposition  of  several  very  fine  laminae  at  the  center,  and  nearly  colorless. 

In  one  portion  of  the  field  is  a  group  of  the  largest  feldspar  crystals 
(described  above)  loosely  interlaced,  and  in  the  interstices  the  augite  has 
developed  so  as  to  fill  the  spaces  and  produce  exactly  the  basaltic  structure. 
Only  where  the  meshes  were  not  closed  do  the  augites  project  oiitward  with 
terminal  faces.  If  the  crystallization  had  continued  undistui-bed  it  would 
have  produced  a  rock  having  exactly  the  texture  of  a  Tertiary  basalt.  As 
it  is,  it  is  plain  that  the  delicate  featherwork  of  feldspar  plates  was  floated 
along  in  the  magma  and  its  crystallization  arrested,  and  one  can  see  that 
the  formation  of  the  basaltic  structure  does  not  necessarily  depend  upon 
the  crystallization,  first,  of  the  feldspar  in  a  network  of  bars,  and  then,  second, 
of  the  augite  in  the  interstices  thus  left,  but  rather  upon  the  different 
methods  of  the  crystallization  of  the  two  minerals  simultaneously;  the 
augite,  having  started  a  crystal  in  contact  with  a  feldspar  blade,  tended  to 
increase  this  to  a  large,  stout  crystal,  while  the  feldspar,  rapidly  shooting  out 
new  blades,  inclosed  and  bounded  the  augite  on  all  sides,  hindei'ing  the  for- 
mation of  crystal  faces. 

Hematite  is  quite  abundant  in  the  rock,  blood-red,  with  botryoidal 
fibrous  structure,  showing  the  black  cross  abundantly,  and  aggregate  polari- 
zation, and  especially  surrounding  the  inclusions  of  quartz  and  microcline. 
It  also  occurs,  with  blood-red  color  and  fibrous  structure,  pseudomorph  after 
olivine.  The  olivine  form  is  sharp  and  clear,  2  P  oo  (021)^99°  15'  (cal- 
culated 99°  06'),  and  this  sharp  dome  is  combined  with  the  prism.  When 
traces  of  the  original  mineral  remain  they  extinguish  longitudinally. 
Irregular  cracks  run  across  the  mineral  as  in  olivine  and  bound  separate 
fibrous  masses,  the  fibers  being  at  right  angles  to  the  fissures.  I  conclude 
that  an  olivine  very  rich  in  iron — a  fayalite — ^lias  changed  into  hematite, 
more  or  less  mixed  with  serpentine.  The  pseudomorphs  are  always  sur- 
rounded by  a  whitish,  semiopaque  halo,  probably  from  the  silicic  acid 
expelled  from  the  primary  mineral.  Other  similar  forms  are  olive-green 
and  polarize  only  in  traces,  and  seem  to  be  olivine  changed  to  serpentine. 
They  have  also  the  white,  opaque  halo.     Very  rarely  a  rounded  grain,  which 


THE  NEWER  (JOKES  AND  SHORT  DIKES.  487 

still  polarizes  l)rilli;uitl>',  is  surrouiuled  by  a  broad  layer  of  fibrous  structure, 
the  fibers  radiatiuyaud  wholly  amorphous. 

MayiictUe  is  rare  and  in  small  grains  only. 

The  groundmass  is  made  up  of  angular  and  rounded  grains  0.001- 
0.005™'"  across,  which  can  at  times  be  seen  to  be  twins,  and  they  seem  to  be, 
in  part  at  least,  augite,  as  they  show  an  extinction  at  42°.  A  specimen 
from  the  north  edge  of  the  dike  has  the  large  feldspars  so  filled  by  these 
minute  augites  that  they  occupy  the  whole  space  as  closely  as  they  do  in 
the  surrounding  groundmass.  Indeed,  it  appears  as  if  a  portion  of  the 
groundmass  having  a  regular  crystalline  outline  had  been  preserved  intact 
from  all  decomposition,  so  that  the  interstices  of  the  grains  have  not  been 
filled  with  the  fine  dust  of  limonite,  kaolin,  etc.,  which  renders  the  rest  of 
the  ground  clouded.  With  polarized  light  the  grains  are  seen  to  be  optic- 
ally orientated  in  the  feldspar,  as  they  extinguish  together,  and  the  feldspar 
bands  can  be  distinctly  seen  shining  through.  The  groundmass  is  for  the 
most  part  the  same  in  the  portions  included  in  the  large  feldspar  crystals  as 
outside,  but  some  inclusions  are  red-brown  and  apparently  glass.  I  can  not 
detect  with  certainty  any  glass  in  the  groundmass  itself  The  inclusions 
are  plainly  from  granite :  quartz  with  sheets  of  pores,  some  containing  mov- 
ing bubbles,  and  rutile  needles,  microcline,  centrally  decomposed  albite  with 
extinction  angle  4°,  and  orthoclase.  Fragments  of  granite  with  feldspars 
wholly  altered,  and  of  an  amphibolite  quite  fresh  and  closely  resembling  the 
fine-grained  rock  at  the  northeast  corner  of  Amherst,  also  occur. 

A  specimen  from  the  first  cleared  field  north  of  the  brook,  externally 
hke  the  last,  shows  both  the  feldspars  and  the  augite  perfectly  fresh  and 
colorless,  sharply  defined,  and  distantly  scattered  in  the  ground.  There  is 
so  much  hematite  that  it  takes  up  a  considerable  portion  of  the  surface. 
One  quartz  inclusion  is  surrounded  by  a  colorless  radiated  fibrous  layer,  and 
outside  this  by  a  broad  band  of  hematite.  The  hematite  so  often  sun-ounds 
the  foreign  inclusions  in  a  rock  otherwise  fresh  that  one  is  tempted  to 
assume  it  to  have  been  a  cement  covering  the  grains  before  their  envelop- 
ment in  the  lava. 

A  great  number  of  bodies  are  present  having  exactly  the  shape  of 
olivine  crystals  and  a  bright-yellow  or  red  color.  The  yellow  scarcely 
polarizes  at  all,  some  few  fibers  or  isolated  spots  showing  faint  color,  and 
it  seems  to  be  a  yellow  serpentine  pseudomorph.     The  red  shows  a  peculiar 


488  GEOLOGY  OP  OLD  HAMPSHIEE  COUNTY,  MASS. 

aggregate   or    patchy   polarization,   and  seems  to  be    a   hematite  pseudo- 
morph  after  ohvine. 

Another  specimen  from  the  vicinity  of  the  last  has  a  very  difiFerent 
structure.  In  a  granular  groundmass  (0.01-0.02™°^)  there  are  regularly 
disseminated,  well-formed  octahedra  of  magnetite,  visible  with  a  lens  in  the 
slide,  and  abundant  diabantite-filled  cavities.  Small  lath-shaped  plagioclases 
and  augites  are  distantly  scattered  and  inconspicuous.  The  rock  resembles 
that  of  the  dike  from  the  house  south  of  the  ruined  leather  mill  below 
Mount  Tom  station,  on  the  west  of  the  river. 

The  above  descriptions  had  been  written  before  I  received  the  first 
accounts  of  Mr.  Diller's  discovery  of  quartz-basalt  at  the  Cinder  Cone,  in 
California.  On  sending  him  fragments  of  the  rock  here  described,  he  wrote 
that  the  quartz  resembled  closely  that  of  the  Cinder  Cone,  and  was  more 
abundant. 

It  will  be  seen  from  my  own  descriptions  that  the  idea  that  the  quartz 
was  original  in  the  rock  had  not  occurred  to  me.  It  does  certainly  resem- 
ble the  Cinder  Cone  quartz  very  closely,  and  it  is  hard  to  see  how  a  great 
quantity  of  foreign  sand  could  be  included  in  an  erupted  dike,  and  espe- 
cially how  it  could  fail  to  bring  with  itself  moisture  enough  to  make 
the  rock  vesicular.  The  shapes  of  the  grains  and  the  high  greasy  luster 
are  not  like  granite-quartz.  I  have  not  been  able  to  verify  my  obser- 
vation that  the  slides  contain  microcline  and  mica,  as  the  slides  are  not 
now  a,ccessible,  but  the  presence  in  the  diabase,  among  many  quartz 
grains,  of  a  large  fragment  (5"'"  across)  made  up  of  quartz  and  orthoclase 
is  certain.  The  quartz  was  exactly  the  same  rounded,  bluish,  greasy  quartz 
as  the  rest,  and  the  flesh-colored  feldspar  gave  the  optical  tests  of  orthoclase, 
so  that  I  feel  quite  certain  that  the  unusual  constituents  have  come  in  as 
foreign  inclusions. 

The  structures  produced  by  the  introduction  of  this  large  amount  of 
foreign  material  into  the  liquid  trap  resemble  those  described  from  the 
Greenfield  bed  in  Chapter  XIII  (p.  419),  where  the  sand  has  risen  up  into 
this  lava  from  below.  This  locality  was  studied  many  years  ago,  before 
the  Grreenfield  and  Holyoke  beds  were  understood,  and  I  can  not  say  what 
modification  of  the  above  description  might  come  from  a  new  examination 
of  the  place  with  new  light.  The  blue  color  of  the  quartz  may  be  due  to 
tension  produced  by  heating,  or  the  quartz  may  be  derived  from  Algonkian 
blue-quartz  gneiss.     (See  page  29.) 


o 


488 


(I- 
is  iHji 

as  till;  .^. 

SO  that  I 

foreign  inck 

The  str 


oreif(n  mat«  rial 


Cireenfield  b 


this  lava  fron  b^-^' 


the  Greenfie 
raodificatiou 
of  the  place 


'  ;  ■    '■ 


■•^Hiin  onrycrft-^  u,j,>; 


I    §ir^of  tlie|j 
j^     5,  (fi.Ol-O.OiJi 
^  -6'Li'32'Metite,^i.' 


imui 


icmaiue  p.-^-cai 

has  a  very  differ*  nt 
there   are  regulaily 
e  with  a  lens  in  \ 
tli^haped  plagioola  ,e.s 
lie  rock  resembles 


i  the  ill 
Cone, 


seen  '.             \ 

0    5 

i  the  rock        y 

0 

r  (joiif  <pi;irtz  ^ 

'    COLtlii 

mil    to 

it 

TIm.  . 
•ontain 

\  y 

ler*.'  '/(.'.smoeti.  hi-  wi 
i^'  /  -.-as  TiK 


it  ■ 

iV(- 


u.seii   inoi.stiii'e 
H  2Tains  aid  the, 


)f)s  certainly  re^^e  ii 
;o  sue  how  a  g-r,  lat 
erupt  3d  dike,  and  esjic!- 
enough  to  nuillcr 
high  gi'easy  lus 


:or 
r- 


tot  been   ible  t/>  verify  my  obs 

and  m|ica,  a|  the  slides  are  i.ot 
the    diabiise,  ai« 


ua 


ict. 


d  in  1. 


dai 

of  tlie  a'' 
with  uvjH' 


y  fei 

A 

^S- 

A 

i"^ 

\ 

^  e 

CM      \ 

^^ 

5  \ 

31 

^  ) 

II 

V 

lonjj-    iiiaiu 
^  ade  iiplof  ijuliitz  and  in-tiiocl; 
$>-  '•  rounded,  blsish,  ffrf^asy  qua 
<5^  g:c  tlii  op^;al  \^sts  of  orthocla 

2    &■  !  .•.  aistitcftmit^ 


liav<'  oorno 


iipii  of  this /large  amount  oi 
jiost'  deBcribed  from  <|li 
iie  sandfhas  i-isen  wv 
•  •;ny|years  ago.  1mi,» 
,can  M(»t  ..ix  V 
a  Yie^^' 


•St 
in 


f/ 


1/ 


in  produced  by  heat 
I uartz  gneiss.     (See  pa 


i  ■<-■  m  % 


•m: 


O     tu 

o   8 


>     E 


THE  NEWER  CORES  AND  SUORT  DIKES.  489 

THE   TENTH   CORE. 

The  w()(mI  road  that  runs  north  into  the  mountain  west  of  Moody 
Corners  branches  after  crossing  the  eleventh  trap  mass,  and  the  western 
branch  in  a  few  rods  runs  out  on  the  sands  of  the  large  Glacial  lake 
described  below.  Here,  at  a  pair  of  bars  giving  entrance  to  the  field, 
near  a  small  brook,  begins  a  long  outcrop  of  trap,  which  continues  50 
rods  west,  forming  the  bluff  which  made  the  south  shore  of  the  lake. 
The  coarse  arkose  surmounts  it  on  the  south,  and  it  is  by  the  downward 
pitch  below  the  sands  of  this  sandstone  on  the  east  and  the  west  that  the 
outcrop  of  the  trap  in  those  directions  is  limited,  while  the  sands  conceal  its 
northern  limit.  Near  its  western  end,  where  a  stone  wall  runs  across  the 
sands,  at  the  foot  of  a  marked  bluff,  the  sandstone  resting  on  the  trap  can 
be  seen  to  be  well  baked  by  it,  and  as  the  trap  is  wholly  fine-grained  and 
without  steam  holes  it  is  plainly  intrusive. 

THE  ELEVENTH  OR  BLACK  ROCK  CORE. 

Looking  southeast  from  the  Mountain  House,  on  the  top  of  Mount 
Holyoke,  one  sees  a  prominent  ridge  of  dark  rock  running  parallel  to  the 
mountain — indeed,  duplicating  it  on  a  smaller  scale,  repeating  its  easy 
southern  slope  and  sharp  northward-facing  bluff  and  making  with  it  the 
great  sweeping  curve.  It  differs  radically  from  it  in  its  origin,  the  larger 
deposit  having  been,  as  I  have  shown,  a  bed  spread  out  over  the  subjacent 
sandstone,  and  this  an  injected  dike  cutting  across  the  latter.  (See  PL 
IX,  p.  446.)  This  bluff,  as  seen  from  the  mountain,  is  called  "The  Black 
Rock,"  and  I  have  chosen  this  name  to  designate  the  core,  and  also  the 
whole  series  of  the  newer  trap  intrusions.  Seen  from  the  west  side  of  the 
river  above  Smiths  Ferry,  it  simulates  exactly  a  volcano  with  sharp  slopes 
and  central  depression. 

The  core  is  best  studied  at  Batterson's  quarry,  in  the  northwest  corner 
of  South  Hadley,  near  the  last  house  (E.  H.  Lyman's)  before  the  town  line 
is  reached.  As  seen  in  the  accompanying  view  (PI.  X),  the  nearly  horizon- 
tal sandstones  are  a  remnant  resting  with  their  edges  against  the  diabase. 

The  latter  not  only  cuts  across  the  sandstone  at  this  point,  but  sends 
into  it  apophyses  of  finer  grain  than  the  main  mass,  which  have  altered  the 
sandstones  in  places  for  4  feet  from  the  contact  and  have  fused  themselves 
into  firm  union  with  the  latter  at  their  junction.  The  thin-bedded  mica- 
ceous sandstones  are  delicately  plicated  by  the  intruded  trap. 


490  GEOLOGY  OF  OLD  HAMPSHIEB  COUNTY,  MASS. 

Following'  the  vertical  wall  of  the  diabase  north  335  feet  from  the 
quarry — a  wall  which  is  the  contact  surface  against  wliich  the  sandstones 
formerly  rested — one  comes  upon  a  most  interesting  point,  where  this  wall 
is  continued  as  sandstone,  a  fine  contact  being  exposed,  and  the  boundary 
line  of  the  diabase  and  sandstone  goes  into  the  hill  at  a  right  angle.  Climb- 
ing to  the  top  of  the  bluff,  one  can  follow  this  contact  east,  the  sandstone 
at  a  distance  of  4  feet  from  the  diabase  being  baked  into  a  dark-blue, 
hornstone-like  rock.  When  the  boundary  bends  round  from  east  to  north 
the  thin-fissile  sandstones  have  the  imusual  position,  strike  N.  70°  W.,  dip 
40°  E.,  being  thus  thrown  off  from  the  eruptive  rock.  Continuing,  the 
boundary  returns  westwardly,  and  thus  embraces  a  great  projection  of  the 


FiQ.  27. — Section  of  contact  of  Black  Kock  plug  and  the  Mount  Holyoke  diabase  bed. 

sandstone  which  extends  far  into  the  diabase,  and  then  turns  round  to  the 
east,  parallel  to  the  direction  of  the  older  bed. 

For  a  long  distance  one  can  follow  up  the  bed  of  Dry  Brook  I'unning 
on  the  back  of  the  older  diabase,  while  its  left  (south)  bank  is  a  vertical 
wall  of  sandstone  dipping  southward  and  ending  abruptly  against  the 
diabase  of  the  Black  Rock  dike,  as  indicated  in  fig.  27. 

At  the  point  where  the  first  outcrop  of  the  sandstone  on  the  brook 
appears,  about  590  feet  from  the  contact  in  the  vertical  wall  last  described, 
occurs  a  curious  metamorphosed  limestone-breccia,  with  garnet,  near  the  base 
of  the  sandstone.  This  nearness  of  the  two  diabase  bodies  continues,  and 
one  goes  east  a  long  distance  thi-ough  a  valley  with  its  right  or  north  side 


THE  NEWER  COKES  AND  SHOliT  DIKES.  491 

till-  back  of  the  main  diabase  bed,  rising  gradually  north  to  the  Holyoke 
House,  its  left  or  south  side  the  vertical  wall  of  the  Black  Rock  dike,  its  face 
veneered  to  a  varying. distance  upward  with  the  remains  of  the  sandstone. 

When  one  comes  out  where  one  can  look  down  on  the  cleared  sand  flats 
of  the  post-Glacial  lake  mentioned  above,  one  sees  that  the  boundary  of  the 
Mount  Holyoke  bed  continues  east,  while  that  of  the  great  crater  swings 
round  southeast  and  extends  to  the  deep  gorge  of  the  little  brook  which 
drains  the  basin  of  the  lake  above  mentioned,  and  has  cut  deeply  through 
the  diabase  to  enter  Elmer  Brook,  just  north  of  H.  White's.  The  diabase 
continues  to  rise  high  and  to  carry  a  thin  remnant  of  the  sandstones  in  con- 
tact with  its  vertical  face,  which  sandstone  shows  contact  effects  and  can 
often  be  plainly  seen  to  abut  against  and  not  to  underlie  the  volcanic  rock, 
toward  which  it  dips.  Wliere  the  boundary  of  the  diabase  runs  southeast 
the  sandstone  preserved  its  east-west  strike  in  the  main,  but  in  places  dips 
toward  the  diabase  with,  the  abnormally  high  angle  of  80°. 

At  the  west  end  of  the  mass  the  diabase  appears  in  the  road  at  the 
Lyman  house,  and  its  westward  extension  is  concealed  by  sands.  This  is 
also  the  case  with  its  southern  border.  The  outcrop  at  the  point  where 
Elmers  Brook  ci'osses  the  road  is  so  brecciated  and  its  fissures  are  so  filled 
with  druses  of  small  rhombohedra  of  hematite  that  it  is  probably  near  the 
southern  contact. 

On  following  the  southern  edge  along  to  a  point  about  north  of  the 
schoolhouse,  where  the  road  to  South  Hadley  starts,  it  is  seen  that  sand- 
stones appear  on  the  south  of  the  trap,  strike  N.  65°  E.,  dip  15°  S. — fine- 
grained, calcareous  sandstones,  blue-black  as  if  baked  or  loaded  with  vol- 
canic ashes,  and  rusting  slowly  inwardly,  like  the  diabase,  and  between 
them  and  the  diabase  is  a  band,  apparently  10  to  15  feet  wide,  of  the  most 
perfect  tuff,  made  up  wholly  of  angular  trap  fragments  of  the  size  of  a  pea, 
with  here  and  there  one  as  large  as  an  acorn,  all  greatly  decomposed.  The 
exact  relation  of  the  tuff  to  the  other  beds  could  not  be  made  out. 

The  boundary  can  be.  closely  followed  eastward  to  the  brook  east  of 
White's  wood  road,  to  which  the  northern  boundary  has  already  been 
followed.  The  exact  contact  can  not  be  seen,  but  the  dark  rusting  sand- 
stones dip  south  away  from  the  diabase,  while  the  latter  rock  in  the  imme- 
diate proximity  to  the  contact  (6  to  8  feet  distant)  is  compact,  coarse- 
grained, and  not  porous. 


492  GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

Approaching  the  brook  the  boundary  bends  northeast,  as  that  on  the 
north  side  had  bent  southeast,  and  down  the  slope  to  the  brook  the  diabase 
is  amygdaloidal  where  nearest  the  sandstone.  The  boundaries  have 
approached  each  other  so  that  in  the  deep  side  of  the  narrow  brook  gorge 
only  a  fourth  of  the  width  of  the  great  mass  appears,  but  this  is  well  exposed, 
and  a  great  talus  of  fragments  of  a  quite  coarse  diabase  makes  up  the  greater 
portion  of  its  width.  The  bottom  of  this  narrow  gorge  is  covered  with  sand. 
In  its  opposite  east  wall  one  can  trace  from  the  south  the  southward-dipping 
tuffs,  and  from  the  north  in  fine  cliffs  the  light-buff  sandstones  with  the  same 
dip,  to  where  they  approach  the  eastward  continuation  of  the  diabase ;  and 
although  the  contacts  are  covered,  it  can  be  pretty  plainly  seen  that  from 
both  sides  the  sedimentary  rocks  abut  against  the  diabase.  The  latter  is  very 
fine-grained  and  has  only  a  small  fraction  of  the  .width  it  had  on  the  other 
side  of  the  gorge.     This  gorge  is  1  mile  northwest  of  Moody  Corners. 

Going  east  it  cuts  through  the  tuff,  and  where  this  is  coarse  and  both 
are  decomposed  it  is  very  difficult  to  separate  them.  In  one  place  the  dia- 
base is  quite  coarse,  light-colored,  and  greenish  from  the  abundance  of 
diabantite,  like  that  just  east  of  White's  wood  road,  and  like  the  rock  of 
the  Deerfield  bed  at  the  Deerfield  Notch.  Followed  still  farther  east, 
where  it  is  crossed  by  the  wood  road  north  from  Moody  Corners,  the 
diabase  is  on  the  north  dark,  fine-grained,  and  bounded  on  the  north  by 
sandstones  which  for  a  long  distance  east  abut  against  the  high  wall  of 
the  diabase,  as  already  described.  Its  boundary  against  the  tuffs  on  the 
south  is  less  clear.  Where  the  road  crosses,  the  distinctly  columnar  diabase 
rises  in  a  ridge  about  35  feet  wide,  and  yet  in  this  is  a  mass  of  tuff  nearly  a 
meter  across,  containing  fragments  of  granite.  To  the  south  a  narrow 
swamp  separates  it  from  a  rock  which  seems  to  be  a  coarse  volcanic  agglom- 
erate made  up  of  angular  fragments  often  10  to  16  inches  across,  which  in 
much-weathered  exposures  can  hardly  be  distinguished  from  the  normal 
diabase. 

PETROGRAPHICAL  DESCRIPTION. 

1.  A  section  taken  from  the  second  outcrop  by  the  roadside  going  in 
from  Mr.  Lyman's  house  and  Batterson's  quarry  is  the  typical  gray  diabase, 
not  distinguishable  by  the  lens  from  the  Iron  Gate  rock  taken  as  a  type 
above  (page  461),  and  the  microscope  reveals  little  distinction  between  the 
two,  either  in  structure  or  stage  of  decomposition.     Pyrite  occurs  in  excep- 


THE  NEWER  COUBS  AND  SHOKT  DIKES.  493 

tional  almiidiuu'd.     Tlie  feldspars  are  wholly  decomposed  and  the  rock  is 
full  of  spots  of  diabautite. 

2.  In  various  sections  cut  from  specimens  taken  at  different  distances 
up  to  3,300  feet  from  the  edge  of  the  dike  no  distinction  could  be  observed, 
but  in  one  taken  from  very  near  the  center  the  augites  were  in  large,  dis- 
tinct crystals,  very  abundant,  and  plainly  anterior  to  the  feldspars. 

3.  Slides  taken  from  the  south  edge  of  the  dike,  where  Elmers  Brook 
finally  leaves  the  trap,  showed  a  large  development  of  the  finely  granular 
groundmass  (grains  0.005°™)  so  common  in  the  rock  of  the  tenth  dike. 

4.  Sections  were  cut  from  the  long,  narrow,  eastward  prolongation  of 
the  dike  where  the  Moody  Corners  wood  road  crosses  it  and  at  its  inter- 
section by  the  two  roads  next  east.  They  resemble  the  type  closely.  The 
augite  is  in  the  main  subsequent  to  the  feldspars,  but  is  a  little  more  dis- 
tinctly individualized  in  long  blades.  Olivine  changed  to  an  olive-green 
serpentine  and  distinct  traces  of  the  unaltered  mineral  occur  sparingly. 

5.  In  sections  cut  from  the  edge  of  the  small  apophyses  sent  off  by 
the  main  mass  into  the  sandstone  and  exposed  in  Batterson's  quarry,  we  get 
additional  proof  that  the  larger  feldspars  are  of  earlier  consolidation.  These 
porphyritic  feldspars  are  of  the  common  size,  1  to  2™™  across,  and  are  asso- 
ciated with  deep-green,  well-formed  olivines  in  an  extremely  fine-grained 
groundmass,  so  that  it  seems  that  they  had  already  separated  out  in  the 
magma  before  its  injection  into  the  narrow  fissure  in  the  sandstone,  in  which 
it  cooled  so  rapidly  that  the  customary  ophitic  structure  was  not  produced 
but  was  replaced  by  the  semicrystalline  development  described  below. 

The  main  groundmass  is  a  felted  mass  of  finest  fibers  0.0016"""  across, 
quite  possibly  feldspar  microlites,  which  are  not  rigidly  straight,  but  wavy, 
often  beaded,  and  are  clearly  margarites ;  generally,  however,  they  polarize 
distinctly.  These  fibers  have  a  radiated  arrangement,  which  gives  the 
whole  groundmass  a  spherulitic  structui-e.  The  fibers  polarize  sheafwise, 
although  they  are  not  parallel. 

The  presence  of  olivine  in  the  fresh  fine-grained  diabase  dikes  in  the 
granite,  and  especially  in  the  minute  dikes  I  have  described  (p.  416),  as 
also  its  presence  in  the  newer  diabase  of  the  volcanic  plugs,  particularly  in 
that  one  which  has  been  described  as  so  full  of  quartz  grains  (p.  483),  may 
seem,  when  contrasted  with  the  absence  of  olivines  in  the  great  Deerfield 
and  Holyoke  beds,  to  indicate  that  the  two  former  occurrences  are  to  be 


494       GEOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 

associated  together  as  of  the  same  age  and  contrasted  with  the  two  latter 
and  older  occurrences;  but  olivine  occurs  in  considerable  abundance  in  the 
base  of  the  Holyoke  bed  at  the  west  foot  of  Provens  Mountain  in  Westfield. 
It  is  strange,  however,  that  where  the  inclusions  of  quartz  are  most  abun- 
dant olivine  is  also  most  abundant. 

NORTHAMPTON. 
THE    TWELFTH   OR   BURNT    MILL    CORE. 

Beneath  the  railroad  bridge  over  the  brook  which  crosses  the  railroad 
a  mile  above  Smiths  Ferry  the  contact  of  the  sandstone  dips  steeply  south- 
east beneath  the  postei'ior  trap,  and  this  contact  can  be  followed,  clearly 
exposed,  along  the  south  side  of  the  brook  beneath  the  road  bridge  and 
past  the  ruined  leather  mill,  and  along  the  south  side  of  the  mill  pond. 
The  conformable  posterior  trap  bed  extends  southeast  of  this  line.  (See 
p.  465.)  Just  north  of  the  brook  and  below  the  dam  one  sees  the  outcrops 
of  an  intrusive  dike  or  plug,  which  comes  up  apparently  along  a  transverse 
fault  that  can  be  traced  west  across  the  mountain  from  this  point.  The  trap 
cuts  across  the  strata  of  sandstone  that  underlie  the  posterior  trap  bed  at 
every  angle,  and  adjacent  to  the  north  end  of  the  dam  bakes  the  sandstone 
for  6  or  8  feet,  so  that  the  line  of  contact  between  trap  and  sandstone  is 
seen  with  difficxilty. 

A  long  ridge  of  the  trap  extends  west  along  the  northwest  side  of  the 
pond,  and  appears  also  on  its  south  side,  and  can  be  followed  thence  south 
for  20  rods.  At  the  water's  edge  trap  and  sand  are  confusedly  blended. 
In  the  bluff  above,  just  south  of  the  head  of  the  pond,  appears  a  well-marked 
fault.  The  posterior  trap  abuts  on  the  sandstone.  It  is  the  continuation  of 
the  Mount  Tom  fault,  and  the  newer  trap  comes  up  at  the  intersection  of 
the  two  faults.  A  large  part  of  the  trap  is  fresh,  compact,  and  breaks  with 
sharp  splintery  fracture;  a  portion  of  the  surface  is  crumbly  and  much 
weathered.     This  represents  a  part  of  the  surface  of  the  old  laccolith. 

The  trap  of  the  plug  may  be  followed  down  the  brook  on  its  north 
side  to  the  road,  and  just  east  of  the  road  several  offshoots  from  it  appear  on 
both  sides  of  the  brook.  On  the  north  is  a  4-foot  dike,  on  the  south  a  4-inch 
dike  at  the  water's  edge  and  a  1-foot  dike  a  few  feet  up.  The  latter  con- 
tinues under  the  road  to  the  dam.  A  few  rods  farther  east  one  comes 
upon  the  most  southern  of  two  outcrops  of  trap  at  the  Lyman  railroad 
crossing,  which  is  doubtless  the  eastern  edge  of  the  plug,  since  it  is  com- 


THE  NEWER  CORES  AND  SMALL  DIKES.  495 

posed  of  the  same  type  of  trap  aud  contains  as  inclusions  portions  of  coarsely 
araygdaloidal  trap,  derived  doubtless  from  the  posterior  trap  sheet,  or  the 
tuff,  through  which  it  has  been  intruded. 

THE  SMITHS  FERRY  CORE. 

Directly  opposite  the  Smiths  Ferry  station  and  at  the  edge  of  the  low 
ten-ace  sands  just  south  of  the  extensive  dog  kennels  the  tuff  is  interrupted 
by  an  area  of  trap,  about  6  rods  on  a  side,  which  seems  to  be  intruded 
through  the  tuif,  since  it  has  angular  masses  of  the  tuff  6  inches  across 
included  in  its  mass.  It  does  not  rise  above  the  level  of  the  tuff,  as  is  usual 
with  the  more  compact  plug  trap,  and  I  at  first  considered  it  a  portion  of 
the  surface  of  the  posterior  sheet  exposed  where  the  tuff  had  been  worn 
tlirough,  but  the  inclusions  of  trap  are  foreign  to  the  posterior  sheet  and  the 
erosion  of  the  old  lake  shore-line  may  have  lowered  the  plug  at  this  point. 
(See,  however,  page  474.) 

CORE  AT  THE  ELECTRIC  RAILROAD  CROSSING  OF  ROARING  BROOK. 

Where  the  Holyoke  Electric  Railroad  track  leaves  the  main  road  to 
go  to  Forest  Park  it  crosses  Roaring  Brook.  Just  south  of  this  crossing  is 
a  surface  of  trap,  exposed  by  the  excavations  for  the  road,  which  is  weath- 
ered and  breaks  up  into  spheres  at  the  surface  and  rests  on  the  sandstone 
in  the  brook  just  below.  This  is  the  south  exposure  of  the  posterior  trap 
sheet.  Just  across  the  brook  the  raih'oad  cutting  exposes  a  splintery  trap  of 
fine  grain  and  perfect  freshness,  which  seems  to  be  the  southernmost  of  the 
small  plugs  accompanying  the  posterior  sheet. 

SUIVOIAEY  OF  HISTORY  OF  THE  COISTSTECTICTTT  RIVEK  SAlSTDSTOlSnE. 

The  mountain-making  forces  which  folded  up  the  Appalachian  chains 
acted  against  the  mass  of  the  Archean  rocks  in  the  Adirondacks,  as  seen 
by  the  great  curve  which  these  chains  make  as  they  run  southward  beyond 
its  influence.  The  outlines  of  the  Connecticut  Basin  were  laid  in  pre- 
Devonian  time,  since  the  Bernardston  Devonian  is  bordered  by  shore  con- 
glomerates which  coincide  with  the  borders  of  the  basin  and  the  later  Hmits 
of  the  Trias.  The  sinking  of  the  great  block  south  of  the  Connecticut 
shore-line,  which  broke  this  curve  of  the  Appalachian  chains,  prepared  the 
way,  perhaps,  for  the  second  admission  of  the  waters  into  this  narrow 
channel,  which  in  shape  and  position  resembled  the  Bay  of  Fundy. 


496       GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

The  tides  of  this  bay  were  ou  a  scale  which  for  a  bay  of  this  width 
have  no  counterpart  at  the  present  time.  They  passed  strongly  np  the 
west  side  and  down  the  east  side,  and  were  here  reenforced  by  the  prevail- 
ing west  winds,  so  that  they  formed  very  coarse  conglomerates  on  the  east. 
The  currents  sweeping  up  the  west  side,  past  shores  and  over  bottoms  of 
coarse  and  deeply  decomposed  granites,  swept  granitic  debris  far  north,  over 
the  area  of  black  schists.  Those  passing  south  swept  argillite  and  quartzite 
debris  far  south  along  the  pegmatite  shore-line  of  the  east  side,  and  the  peg- 
matite material  south  along  the  tonalite  and  schist  terrane,  and  only  where 
the  bay  widened  was  there  in  its  center  an  elaboration  of  quartz  sand  to 
form  the  brownstones.  In  the  narrower  parts  of  the  bay  the  two  shore  con- 
glomerates meet  along  a  central  suture,  so  to  speak,  and  this  ends  so  abruptly 
at  the  north  end  of  the  basin  as  to  suggest  that  it  extended  much  farther 
north  and  was  perhajDS  a  strait  opening  into  a  larger  area  to  the  north. 

The  network  of  faults  which  bounds  and  intersects  this  basin  permitted 
the  sinking  of  its  bottom,  in  which  movement  the  block  from  Amherst  to 
Northfield  participated  in  a  much  less  degree  than  did  the  rest.  In  the 
great  transgression  which  followed,  the  waters  slowly  rose  upon  the  bottom 
and  the  slopes  of  the  basin  and  found  a  great  abundance  of  material  ready 
for  transportation  and  redistribution,  because  the  rocks  had  become  deeply 
disintegrated  during  the  long  period  of  emergence  which  was  now  brought 
to  a  close. 

I  have  examined  both  shores  of  the  Bay  of  Fundy  as  well  as  the 
fiords  of  Norway  and  Scotland,  and  in  comparison  the  work  done  here 
seems  to  me  to  indicate  stronger  currents,  a  larger  amount  of  material, 
more  rapid  change  of  level  of  the  sea,  and  more  rapid  deposition,  than  can 
be  found  in  any  modem  examples.  The  sea  seems  to  have  risen  over  the 
flats  and  slopes  of  deeply  softened  rock  more  rapidly  than  it  could  remove 
the  material,  and  therefore  advanced  without  forming  a  fixed  and  deep-cut 
coast  line.  It  often  moved  the  softened  d^bi'is  in  such  large  quantity  to  its 
present  resting  place  that  it  is  scarcely  sorted  or  rounded  even  when  quite 
coarse  gravel.  Indeed,  the  study  of  this  Triassic  transgression  has  thrown 
more  light  upon  the  ancient  and  more  widespread  Cambrian  transgression 
(Chapter  V)  than  I  have  gained  from  the  examination  of  more  modern 
instances. 

It   is  very  remarkable   how  entirely  the  finest  clayey  material   was 


SUMMARY  OF  HISTOKY  OP  THE  TRIASSIO  BEDS.  497 

\vlioll\-  removed  troTU  the  basin  during  the  deposition  ol"  beds  of  so  great 
thickness.  At  a  certain  time  in  the  midst  of  this  rapid  deposition  came 
the  great  eruptions,  apparently  synchronous,  of  the  Deerfiekl  and  Holyoke 
beds.  The  bottom  of  the  bay  at  this  time  presented  a  surface  covered  in 
(Hfterent  parts  by  beds  of  every  degree  of  coarseness  along  its  borders  and 
grading  toward  the  center  into  finer  beds,  as  is  indicated  by  the  character 
of  tlie  substratum  on  vs^hich  the  trap  beds  rest. 

Along  beneath  the  trap  of  the  Holyoke  range  from  west  of  Mount 
Holyoke  to  beyond  Mount  Tom  much  argillaceous  limestone  is  inclosed  in 
the  trap  at  its  base,  and  in  Holyoke,  at  Ashley's  pond,  the  same  limestone 
occurs  in  the  inclusions  at  the  surface  of  the  same  trap  sheet. 

I  explain  the  above  structure  by  the  imder-rolling  of  the  surface  of 
the  sheet.  A  limited  amoimt  of  calcareous  mud  was  washed  by  the  strong 
convection  currents  onto  the  submerged  surface  of  the  advancing  sheet 
(which  was  superficially  solidified)  and  blended  more  or  less  with  this  sur- 
face, which  by  the  continued  advance  of  the  mass  became  in  part  under- 
rolled,  like  the  surface  of  an  unrolling  carpet,  thus  protecting  the  sand 
below  from  baking,  and  bringing  the  highly  vesicular  trap  loaded  with 
limestone  to  the  base  of  the  bed.  A  similar  structure  occurs  at  the  base  of 
the  trap  sheet  east  of  Greenfield,  but  not  at  its  surface.  This  was  caused 
by  the  frothing  up  of  the  muddy  bottom  into  the  liquid  trap. 

It  is  quite  probable  that  these  trap  sheets  were  poured  out  through 
fissures — the  Holyoke  sheet  through  an  east-west  fissure  passing  beneath  the 
line  of  small  volcanic  cores  a  mile  south  of  the  main  outcrop  of  the  main  bed, 
and  continuing  as  a  north-south  fissure  passing  tlii-ough  the  same  series  of 
plugs  west  of  the  Connecticut.  The  focus  of  most  intense  and  long-con- 
tinued action  was  about  a  mile  south  of  the  point  where  the  river  cuts 
through  the  main  ridge  and  where  these  fissures  intersect.  The  Deei-field 
fissure  can  not  be  exactly  located.  It  was  beneath  or  east  of  the  present 
outcrop,  because  artesian  wells  at  Turners  Falls  cross  the  trap  sheet  just 
east  of  this  outcrop,  and  there  is  no  trace  of  intrusive  trap  west  of  the 
present  western  bluffs.  Its  focus  was  probably  just  east  of  Greenfield. 
These  sheets  produced  no  disturbance  in  the  distribution  of  sediments  and 
almost  no  tuffs,  and  the  arkose  which  covers  them  is  often  buff  and  nearly 
free  from  iron  and  lime.    . 

The  sands  which  spread  over  the  basin  soon  covered  the  great  trap 

MON  XXIX 32 


498  GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

sheets,  and  then  a  second  period  of  volcanic  activity  followed.  The  lava 
broke  out  at  a  point  on  the  fissure  through  which  the  older  lava  had  come, 
and  flowed  in  a  broad  sheet  down  the  bottom  of  the  valley.  The  place 
where  the  lava  came  up  is  preserved  in  Little  Mountain,  east  of  Mount 
Tom,  and  the  outcrop  of  the  lava  sheet  extends  north  and  south  from  here, 
and  has  been  described  as  the  posterior  sheet. 

The  next  episode  in  the  history,  following  immediately  on  this  outflow 
of  lava,  was  an  explosive  eruption  of  diabase  forming  the  beds  of  tuff  from 
the  Belchertown  ponds  to  Holyoke.  The  center  of  eruption  seems  to  have 
been  at  the  focus  mentioned  above,  not  far  from  Smiths  Ferry,  since  the 
bombs  there  are  a  foot  across  and  decrease  in  size  in  both  directions.  The 
tuffs  produced  a  marked  change  in  the  fucoidaP  beds  (the  Longmeadow 
sandstone)  above,  into  which  they  grade,  as  compared  with  the  older  beds 
beneath  the  tuff.  By  shallowing  of  the  water  the  beds  are  rendered  finer, 
and  they  are  made  deep-red  and  calcareous  from  the  decomposition  of  the 
tuff.  These  red  beds  extend  south  from  the  lunate  band  of  tuff,  but  this 
tuff  only  accelerated  and  intensified  a  process  which  extended  far  south 
beyond  its  influence,  and  which  had  its  cause  in  the  width  of  the  basin,  its 
shallowness,  and  the  presence  of  northward  cuiTents  along  its  west  side 
and  southward  cvirrents  along  its  east  side.  These  cm-rents  kept  the  sides 
of  the  basin  deeper  and  made  them  a  seat  of  coarser  sedimentation,  and 
between  them  was  a  central  area  of  conflicting  and  shifting  currents— a  sort 
of  Sai'gasso  Sea,  in  which  the  finer  fucoidal  sandstones  were  deposited  and 
so  frequently  exposed  by  the  retreating  tides  that  almost  every  part  shows 
mud-cracks,  rain-drops,  tracks,  thin  films  of  coal,  or  some  trace  of  exposure. 

The  northern  or  Montague  basin  reached  only  this  stage,  the  broad 
development  of  the  central  fucoidal  sandstones,  and  there  was  no  tuff 
outburst  or  development  of  shales.  In  the  wider  southern  or  Springfield 
basin  a  central  area  of  still  greater  quiet  developed  with  the  widening 
of  the  channel,  in  which  at  last  marly  sediments  were  retained  within 
the  area,  marked  by  numerous  salt  pseudomorphs,  and  in  wliich  a  later 
circulation  of  the  waters  has  concentrated  the  lime  into  bands  of  concre- 
tionary limestone. 

'  These  paragraphs  were  written  when  the  rodlike  markings  in  the  "fucoidal"  sandstones  were 
supposed  to  be  plant  remains.  I  now  think  them  to  be  concretions,  as  explained  under  "Plants,"  p. 
395.  There  may  thus  be  added  to  the  effects  of  the  impregnation  with  iron  the  abundant  rod-shaped 
concretions  which  have  been  mistaken  for  plant  remains  and  called  "fucoids." 


SUMMARY  OP  HISTORY  OF  THE  TRIASSIO  BEDS.  499 

The  beds  coutaiuing'  reptile  tracks  are  almost  without  exception  above 
the  great  trap  sheets,  and  in  most  cases  not  very  far  above  them  vertically. 
Some  of  the  localities  situated  far  to  the  east  have  been  brought  up  by 
faulting.  These  central  exposed  mud  flats  seem  to  have  been  caused  by 
shallowing  of  the  waters,  which  resulted  from  the  flowing  of  the  great  sheet 
out  over  the  bottom. 

The  present  dips  are  the  result  of  three  actions  difficult  to  separate: 

(1)  Deposition  upon  an  inclined  plane,  especially  that  between  the 
central  shallower  portion  and  the  deeper  portion  on  the  border.  This 
seems  to  be  the  case  across  Hatfield  and  Deerfield,  on  the  western  side 
of  the  basin,  where  the  finer  central  beds  dip  slightly  west  toward  the 
coarser  beds  near  the  shore,  and  across  South  Hadley,  Springfield,  and 
farther  south,  where  the  finer  central  beds  have  a  low  dip  eastward  toward 
the  shore  beds.  In  these  cases  the  beds  have  been  moved  but  little  since 
their  deposition. 

(2)  A  slight  excess  of  sinking  on  the  eastern  side  or  an  increment  in 
the  strength  of  the  eastern  currents,  or  both,  by  which  the  finer  central 
beds  were  in  their  eastern  portion  encroached  upon  and  covered  by  a 
broad  transgression  of  the  eastern  conglomerates,  so  that  all  down  the  east 
side  the  fine-grained  beds  dip  normally  beneath  the  coarse. 

(3)  Later  tilting,  largely  to  the  east,  but  bending  to  the  south  in  the 
Holyoke  range,  and  generally  of  the  monoclinal  type,  the  important  excep- 
tion being  at  the  mouth  of  Millers  River,  where  there  is  a  great  syncline 
whose  axis  pitches  sharply  a  few  degrees  south  of  west.  By  this  later 
monoclinal  tilting  the  covered  bed  of  fucoidal  sandstone  is  brought  up 
several  times  in  the  mass  of  Mount  Toby. 

A  third  period  of  volcanic  activity  occurred  in  the  southern  basin 
about  the  time  of  the  close  of  sedimentation  and  the  final  tilting  of  the 
sandstones.  Nearly  a  score  of  volcanoes  formed  a  chain  running  from  the 
Belchertown  ponds  first  west  to  the  Connecticut  River  and  then  south  to 
Holyoke,  apparently  caused  by  the  reopening  of  weak  points  along  the 
great  fissures  which  had  supplied  the  material  of  the  earher  sheet.  One  of 
these  shows  indications  of  having  been  a  laccolith  sending  out  a  long 
fissure-filling  in  the  sandstone.  Another  is  diabase  filled  with  granitic 
inclusions.     The  rest  are  small  plugs. 

The  final  tilting  was  much  more  severe  in  the  northern  portion  of  the 


500       GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

basin,  and  has  here  a  large  component  of  north-south  motion,  and  thus  of 
east-west  strikes.  The  limit  of  this  severe  action  is  the  east-west  fault 
mai-ked  by  the  line  of  craters  just  mentioned.  Many  baryta-lead  veins  in 
the  sandstone  and  the  crystalline  rocks  on  its  borders  seem  to  have  been 
formed  at  this  period. 

In  his  review  of  the  question  whether  the  rocks  of  the  Connecticut 
Valley  were  deposited  in  a  separate  basin,  as  has  been  maintained  in  the 
preceding  pages,  or  were  connected  across  western  Massachusetts  and 
Connecticut  and  eastern  New  York  with  the  New  Jersey  Triassic,  which 
culminates  in  the  Palisade  range.  Professor  RusselP  still  maintains  the 
opinion  he  had  advanced  in  earlier  papers.  The  localities  described  in  the 
preceding  pages  where  coarse  conglomerates  and  coarse,  unworn  arkose 
beds  rest  on  the  crystalline  rocks  along  the  western  border,  and  the  relation 
of  these  beds  to  the  great  granite  areas  directly  west,  make  it  quite  certain 
that  the  upper  end  of  the  bay  in  Massachusetts  had  its  western  shore- line 
quite  exactly  at  the  present  western  border  of  the  Triassic  beds.  These 
latter  are  mainly  formed  from  bottom  to  top  of  the  coarse  ddbris  of  mus- 
covite-granites  such  as  now  form  their  western  border,  while  if  they  had 
transgressed  but  a  few  miles  westward  they  would  have  covered  entirely 
all  this  coarse  granite  area,  and  there  is  no  similar  area  from  which  the  arkose 
could  have  been  derived  farther  west,  where  the  shore-line  must  have  been. 

THE  USE  OF  THE  TRAP  AS  ROAD  MATERIAL. 

It  is  well  known  that  the  trap  furnishes  the  best  material  for  road 
making,  and  as  the  legislature  of  Massachusetts  has  wisely  entered  upon 
an  extensive  and  carefully  arranged  scheme  looking  to  the  extension  of 
macadamized  roads  throughout  the  State  those  places  where  the  trap  is 
found  in  large  quantity  and  of  good  quality  and  near  to  railroads  will  be 
of  economic  value.  The  city  of  Springfield  has  for  a  long  time  worked  a 
quarry  at  the  point  in  Westfield  where  the  Boston  and  Albany  Railroad 
crosses  the  main  or  Holyoke  trap  sheet.  Recently  (1895)  the  Massachu- 
setts Stone  Crushing  Company  has  established  an  extensive  plant  on  the 
south  side  of  the  Deerfield  River  at  Cheapside,  with  a  capacity  of  about 
100  tons  per  diem.  The  company  has  spur  tracks  to  the  Turners  Falls 
branch  of  the  Canal  Railroad  and  can  distribute  its  product  readily  by  rail 


^  Correlation  Papers,  The  Newark  System,  Bull.  U.  S.  Geol.  Survey  No.  85,  1892,  p.  101. 


TRAP  AS  ROAD  MATERIAL.  501 

fi'om  Nortliampton  or  Greeniield.  This  work  is  on  the  main  Deerfield 
tru})  sheet.  The  New  England  Trap  Rock  Company,  of  Westfiekl,  has 
opened  another  laa-ge  quarry  on  the  west  line  of  West  Springfield,  on  the 
Ilolyoke- Westfiekl  road,  with  a  spur  track  to  the  railroad  which  connects 
these  towns.  It  has  two  large  crushers  with  a  capacity  of  700  tons  per 
diem,  and  can  deliver  the  rock  on  the  cars  at  65  to  75  cents  per  ton.  A 
crusher  has  also  been  set  up  at  the  west  foot  of  Mount  Tom,  in  Easthamp- 
ton,  which  supplies  this  town  with  road  material.  It  is  directly  under  the 
most  picturesque  portion  of  the  palisaded  bluff,  and  although  it  is  at  present 
working  in  the  trap  talus,  later  the  operations  may  seriously  mar  the  north 
wall  of  the  mountain.  The  great  dike  beside  the  spur  track  of  the  quarries 
of  W.  N.  Flynt  &  Co.,  in  Monson,  has  been  opened  by  that  company,  and 
will  supply  material  of  the  very  best  quality. 

The  city  of  Northampton  has  for  several  years  established  its  cruslaing 
works  near  the  north  line  of  the  town  and  at  a  distance  from  railroads,  and 
works  the  Hatfield  tonalite  or  hornblendic  granite,  which  is  a  partly  decom- 
posed rock,  more  brittle  than  the  trap,  and  in  many  ways  an  inferior  rock 
for  road  ballast.  The  city  has  access  beside  the  road  or  railroad  within  its 
own  limits  to  several  better  ledges  than  the  one  it  works  now.  In  1897  the 
city  of  Ware  opened  a  quarry  on  the  Coys  Hill  dike  on  the  mountain  side 
east  of  the  railroad  station.  The  dike  is  here  5  rods  wide,  favorably  situated 
for  quanying,  and  will  furnish  the  best  material  in  inexhaustible  quantity. 

The  other  localities  where  the  rock  occurs  in  good  quantity  and  qiiality 
and  convenient  of  access  to  the  railroad  are :  Where  the  Fitchburg  Railroad 
crosses  the  Deerfield  trap  sheet,  on  the  north  side  of  the  Deerfield  River 
and  directly  opposite  to  the  present  works;  along  the  Connecticut  River 
Railroad  below  Mount  Tom  station,  especially  at  the  first  crossing,  and  at 
Delaney's  quarry  on  the  north  line  of  Holyoke;  at  Tatham  Cutting,  in  West 
Springfield;  and  finally,  all  the  later  volcanic  cores  marked  on  the  map,  and 
especially  the  dikes  of  the  trap  marked  in  the  crystalline  rocks  on  the  east 
of  the  Triassic  area,  furnish  a  rock  more  fresh  and  firm  than  the  trap  of  the 
main  sheet. 

.  West  of  the  Triassic  no  beds  of  trap  are  found  and  the  hornblende- 
schist  of  Chester  or  the  Becket  gneiss  will  be  the  best  substitute  for 
local  use. 


CHAPTER     XIV. 

MINERAL  VEINS. 

The  only  mineral  veins  in  the  area  are  of  the  "baryta-lead  formation," 
though  in  some  of  the  fissures  occupied  by  these  veins  there  seems  to  have 
been  an  antecedent  "fluorspar-calcite  formation."  Many  of  these  veins  seem 
to  have  been  first  filled  with  fluorspar  and  calcite  and  various  ores.  These 
are  now  scarcaly  represented  except  by  the  many  pseudomorphs  of  quartz 
after  fluor  and  calcite.  The  circulating  waters  bearing  silica  first  dissolved 
out  or  replaced  the  fluor  and  calcite.  This  forms  the  beginning  of  the 
second  stage  of  vein  filling,  and  the  veins  soon  became  quartz-barite-galena 
deposits,  with  chalco23yrite  and  sphalerite  at  times  replacing  the  galena.  It 
is  quite  possible  that  the  fluorspar-calcite  formation  dates  from  the  time  of 
the  post-Carboniferous  folding,  and  entirely  probable  that  the  barj^ta-lead 
veins  coincided  with  the  folding  of  the  Triassic  rocks,  since  they  occur 
both  in  the  Triassic  sandstones  and  in  the  older  rocks. 

All  the  minerals  which  occur  in  the  veins  mentioned  above  are 
described  in  detail  in  the  author's  Mineralogical  Lexicon  of  the  three 
counties^  and  in  the  supplement  to  the  same  in  Chapter  XXII  of  this 
monograph. 

The  other  beds  in  which  mining  is  done — the  emery  bed  and  the  pyrite 
and  hematite  beds  in  the  Hawley  schist — are  in  the  main  contemporaneous ' 
beds,  interstratified  with  the  schists  which  contain  them,  and  the  workable 
ores  were  either  originally  present,  as  in  the  emery  bed,  or  were  formed 
largely  by  replacement  of  other  beds,  so  that  it  has  been  more  natural  to 
discuss  them  in  connection  with  their  coimtry  rock. 

Westliampton ;  the  Londville  vein. — On  July  27,  1679,  the  little  plan- 
tation of  Nonotuck,  now  Northampton,  held  a  town  meeting  and  voted, 
"after  much  discourse  and  agitation,"  that  the  town  have  a  general  interest 

'  Bull.  U.  S.  Geol.  Survey  No.  126, 1895. 
502 


MINERAL  VEINS.  503 

in  a  k'ud  iniue  newly  discovered  within  its  limits.     There  is  but  one  other 

entry  on  this  subject  in  the  early  records  of  the  town,  viz  : 

At  a  legal  meeting  Oct.  16,  1679,  they  then  having  further  Conference  about  the 
lead  mine  which  Robert  Lyman  found  out,  they  then  voted  that  all  such  persons 
as  would  Join  in  the  Carrying  on  of  that  design.  Should  meet  on  the  23d  of  this 
instant  at  Sun  one  hour  high  at  night,  and  to  them  or  to  those  persons  that  shall 
then  appear  the  Town  do  hereby  give  up  all  their  right  in  that  mine  lying  about  six 
miles  otf,  at  the  west  side  of  the  Town. 

It  can  not  be  learned  what  came  of  this  vote,  but  bullets  were  cast 
from  lead  smelted  here  during  the  Revolution.^  The  shaft  was  opened 
before  1769,  and  again  in  October,  1809.  It  was  reported  upon  by  Ben- 
jamin Silliman  in  October,  1810,  and  the  report  was  printed  as  an  article 
in  Brace's  American  Mineralogical  Journal.^  The  shaft  was  then  60  feet 
deep,  the  adit  25  to  30  feet,  and  the  vein  was  "a  very  magnificent  one,  6  to 
8  feet  in  diameter."  In  1815  the  adit  was  726  feet;  the  shaft  entering  500 
feet  from  the  mouth  was  90  feet  deep.^  In  1818  Amos  Eaton  described  the 
rocks  of  the  adit  carefully.  It  was  then  800  feet  deep,  666  feet  in  sand- 
stone, 134  feet  in  granite-schist  and  serpentine,  containing  veins  carrying 
quartz,  fluor,  calcite,  chalcopyrite,  and  one  small  vein  of  galena.*  In  1823 
the  adit  was  990  feet  long  and  had  cost  $20,000." 

In  1827  druses  containing  more  or  less  calcite  crystallized  among  the 
crystals  of  quartz  had  occurred  in  the  last  200  to  300  feet  of  the  adit^  and 
a  company  opened  a  new  mine  with  a  drift  on  what  was  supposed  to  be  the 
same  vein  3  or  4  miles  southwest;  the  vein  being  6  inches  to  a  foot  wide. 
In  the  next  year  the  vein  was  opened  one-half  mile  north.''  In  1832  Presi- 
dent Hitchcock  mentions  with  apparent  regret  that  work  had  been  stopped 
on  the  adit  at  900  feet,  largely  because  the  pi-ice  of  lead  had  decreased 
greatly,  from  western  competition,  and  expresses  the  belief  that  the  vein 
would  have  been  struck  in  a  few  feet.  The  mine  was  opened  again  in 
1855  "with  prospect  of  success."^ 

The  mine  was  again  opened  in  about  1862,  and  I  remember  visiting  it 


'  Evert's  History  of  the  Connecticut  Valley  in  Massachusetts,  Vol.  I,  1879,  p.  17. 

^Ibid.,  Vol.  I,  p.63. 

^E.  Hitchcock:  North  American  Eeview,  Vol.  I,  p.  335. 

"Amos  Eaton:  Am.  Jour.  Sci.,  1st  series,  Vol.  I,  p.  137. 

'■E.  Hitchcock :  Am.  Jour.  Sci.,  1st  series,  Vol.  VI,  p.  201. 

"A.  Nash,  The  lead  mines  of  Hampshire  County:  Am.  Jour.  Sci.,  Ist  series,  Vol.  XII,  p.  258. 

'E.  Hitchcock:  Am.  Jour.  Sci.,  1st  series,  Vol.  XIII,  p.  218. 

8  E.  Emmons,  American  Geology,  p.  183. 


504  GEOLOGY  OP  OLD  HAMPSHIEB  COUNTY,  MASS. 

then,  in  my  freshman  year,  and  rowing  the  length  of  the  adit.  The  Manhan 
Silver-Lead  Company  was  formed,  which  erected  extensive  buildings  and 
installed  expensive  machinery.  I"  have  been  informed  that  the  enterprise 
failed  because  of  the  fall  in  the  price  of  lead  at  the  close  of  the  war,  and 
that  the  machinery,  costing  about  $60,000,  was  sold  to  the  Chester  Emery 
Company  for  about  $17,000. 

The  vein  produced  lead  with  about  12  J  ounces  of  silver  per  ton  from 
galena.  Sphalerite,  chalcopyrite,  pyrite,  and  bornite  occurred  more  rarely; 
barite  and  quartz  in  abundant  ciystals  was  the  gangue.  As  decomposition 
products,  malachite  appeared  with  wulfenite,  cerussite,  and  anglesite,  and 
the  finest  pyromorphite  occurred.  Pseudomorphs  after  calcite  and  fluorite 
*j  indicated  the  former  more  abundant  presence  of  these  gangue  minerals. 

y'^  — ,  The  most  interesting  article  that  has  been  published  on  the  lead  veins 
of  Hampshire  was  by  a  wholly  self-taught  man,  Mr  A.  Nash,  and  this  seems 
to  ha;^e  been  his  only  essay  in  authorship.  Professor  Shepard,  who  then 
did  editorial  work  on  the  American  Journal  of  Science,  told  me  that  it  took 
much  editing  to  make  the  paper  intelligible.  Much  of  what  follows  comes 
from  that  paper.^ 

Whatehj. — This  vein  is  in  the  southwest  part  of  the  town,  on  the 
summit  of  a  high  mountain  of  granite.  The  vein  is  3  to  4  feet  wide; 
considerable  galena  occurs  in  a  quartz  g-angue;  the  range  and  vein  strike 
northeast.     (Nash.)     I  have  searched  for  this  without  success. 

WJiately. — In  the  northwest  part  of  the  town.  The  vein  runs  north 
and  south.  It  has  been  traced  100  yards  to  the  edge  of  Conway.  The 
ends  of  the  vein  are  in  mica-schist;  the  middle  is  in  granite;  6  to  7  feet 
wide.  The  gangue  is  quartz;  the  ore,  galena  only.  (Hitchcock.^)  Shows 
graphitic  slickensides;   crushed  veins  with  quartz,  calcite,  and  green  fluor. 

Conway. — Southeast  part,  3  miles  from  meetinghouse,  and  southeast 
of  the  manganese  vein.  It  contains  quartz  and  galena.  (Nash.)  Maybe 
the  same  as  the  last. 

'  Chesterfield. — A  copper  mine  is  put  down  on  Nash's  map  east  of  the 
Lily  Pond  Brook,  but  not  mentioned  in  the  text. 

Goshen. — Sixty  rods  east  of  Congregational  meetinghouse;  galena  in 
crystallized  masses  of  quartz  on  the  ground;  no  vein  seen.     (Nash.) 

I  Am.  Jour.  Sci.,  1st  series,  Vol.  XII,  p.  238;  map. 
''Am.  Jour.  Sci.,  Ist  series,  Vol.  VI,  p.  204. 


MINEEAL  VEINS.  505 

Williamsburg. — Northeast  part;  vein  not  seen;  larg-e  blocks  of  (quartz 
occur  in  great  profusion  in  a  range  several  rods  wide  and  one-quarter  of  a 
mile  long;  the  quartz  is  radiated  and  rich  in  galena  and  chalcopyrite. 
(Nash.) 

WiUiamshurg. — Vein  runs  northwest,  then  north,  and  then  northeasterly 
into  Whately;  quartz  partly  green  and  amethystine  with  pyrolusite  and 
galena,  which  increases  northerly.     (Nash.) 

WiUiamshurg. — Extending  into  Whately  one-half  mile  east  of  the  above. 
Contains  galena  and  pyrolusite  in  quartz.     (Nash.) 

Williamsburg. — ^At  northwest  corner  of  Northampton,  near  the  argentite 
locality  (see  Mineralogical  Lexicon,^  under  "Calcite").  It  contains  pseudo- 
moi-phs  of  calcite  and  fluorspar;  the  vein  extends  down  the  brook  one-third 
of  a  mile  on  the  east  side.     (Nash.) 

SMburm.—^orih.  of  J.  Dole's,  1  mile  west  of  Shelburne  Center,  at 
southeast  border  of  gneiss  on  contact  of  hornblende-schist  and  mica-schist; 
vein  2  feet  wide,  containing  pyrite,  galena,  blende,  malachite;  runs  N.  25° 
E.,  dip  40°  E. 

Greenfield. — At  junction  of  diabase  and  upper  sandstone,  on  the  west 
bank  of  the  Connecticut,  100  rods  below  the  mouth  of  Fall  River.  It  goes 
north  obliquely  into  the  diabase  and  south  across  the  sandstone  in  the  river 
bed.  The  principal  vein  is  5  to  6  feet  wide.  It  strikes  north-south;  dips 
90°;  malachite  is  common,  the  sulphuret  is  rare.  There  is  a  second  vein 
about  a  mile  below,  and  narrow  veins  with  fine  slickensides  occur  in  other 
places  between.     (E.  Hitchcock.^) 

Turners  Falls.— West  side  of  the  island  at  the  falls;  strike  north-south; 
dip  90° ;  produced  fine  large  masses  of  chalcopyrite  and  much  siderite ;  is 
in  brecciated  sandstone. 

Hatfield. — Vein  appears  in  the  bluff  of  tonalite  about  2  miles  west  of  the 
town,  60  rods  north  of  the  road  to  Williamsburg.  It  can  be  traced  N.  60° 
W.  for  about  30  rods.  A  slanting  shaft  has  been  sunk  from  the  base  of 
the  bluff;  the  vein  is  1  foot  at  surface  and  3  feet  at  bottom.  Farther  west 
the  vein  has  been  opened  about  20  feet  deep ;  it  is  here  4  feet  wide  at 
surface  and  8  feet  at  bottom.  Back  from  the  vein  the  tonalite  seems  very 
fresh,  but  under  the  microscope  its  feldspar  is  always  much  kaolinized. 

'  Bull.  U.  S.  Geol.  Survey  No.  126,  189.5. 
=  Am.  Jour.  Sol.,  1st  series,  Vol.  VI,  p.  207. 


506  GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

For  several  feet  on  the  border  and  in  the  numerous  "  horses  "  it  is  changed 
to  a  plainly  kaolinized  white  mica-granite,  most  or  all  the  hornblende  being 
removed.  It  contains  rarely  green  fluor  and  calcite,  R',-^R,  weathered  to 
dull  gray  and  both  in  every  stage  of  change  to  hollow  pseudomorphs  of 
quartz.  The  main  filling  of  the  vein — following  the  above  calcite-fluor 
stage — was  quartz,  itself  covered  by  barite,  which  so  abuts  against  the  quartz 
with  its  prismatic  faces  that  the  latter  seems  to  be  the  newer  mineral,  which 
is  rarely  the  case.  Galena,  blende,  pyrite,  chalcopyrite  are  the  ores.  A 
second  generation  of  calcite,  R,  R^,  occurs  in  the  quartz.  Cerussite,  mala- 
chite, pyromorphite,  limonite,  and  pyrolusite  are  the  decomposition  products. 

Leverett. — One  mil6  northwest  of  the  meetinghouse,  on  land  of  Mr. 
Field,  once  considerably  worked,  but  abandoned  on  account  of  its  unprom- 
ising appearance.  (Nash,  1827.)  Was  worked  by  a  company  organized  in 
New  York  a  few  years  ago,  but  did  not  pay.-'  Strike  north-south;  dip  90°. 
(E.  Hitchcock.)  The  vein  is  in  mica-schist  and  granite.  It  is  several  feet 
wide,  and  contains  galena,  chalcopyrite  in  masses  of  the  size  of  one's  fist, 
blende  in  the  best  crystals  obtained  from  any  of  the  veins,  and  pyrophyl- 
lite.  The  gangue  is  baryta.  Hollow  quartz  pseudomorphs  after  pyro- 
phyllite  occur. 

Leverett. — South  line,  "White  Rock  quarry."  Only  few  inches  wide 
at  surface,  but  widening  below.  Galena  and  chalcopyrite  abundant  at  sur- 
face, but  rare  below ;  worked  but  few  feet  down,  there  1  foot  wide ;  nearly 
pure  barite.  (Nash.)  Later  a  long  adit  was  driven  in,  but  caved  many 
years  ago. 

Leverett. — Cut  south  of  railroad  crossing  next  east  of  last  mine;  narrow 
veins  of  barite,  with  little  galena. 

Northampton. — At  the  quarry  east  of  Florence,  in  Northampton  (south 
of  W.  N.  Moore's  house),  the  biotite-muscovite-granite  is  cut  by  joints  run- 
ning N.  60°  E.  and  dipping  60°  N.  These  joints  are  about  a  foot  apart  and 
in  this  and  in  the  next  quarry  to  the  east  are  often  marked  by  fine  slicken- 
sided  surfaces.  Between  two  of  these  fault  planes  a  sheet  of  the  granite 
is  finely  crushed  and  the  parts  recemented,  producing  a  great  crush  fault 
which  runs  beyond  the  limits  of  the  quarry  in  both  directions.  The 
fissures  thus  produced  were  occupied  first  by  calcite,  which  is  now  present 
only  in  a  few  crystals  coated  with  transparent  cubes  of  fluor,  but  is  further 
represented  by  negative  crystals  in  barite  and  quartz.     Barite  followed  the 

'  Evert's  History  of  the  Connecticut  Valley  in  Massachusetts,  Vol.  II,  1879,  p.  73.3. 


MINERAL  VEINS.  507 

cuk'ite  and  sliot  out  through  nil  the  cavities  in  broad  plates  of  extreme 
thinness.  This  Avas  followed  by  an  abundant  deposition  of  quartz,  both  as 
drusy  surfaces  and  as  pseudomorphs  after  calcite,  and  by  barite.  There 
is  idso  an  abundance  of  a  chocolate-colored  tabular  quartz,  slashed  full  of 
fissiu-es  from  which  the  blades  of  barite  have  disappeared,  which  is  a  most 
perfect  pseudomorph  after  the  peculiar  tabular  form  of  calcite  called  argen- 
tine, which  occurs  also  on  the  other  border  of  the  great  granite  area. 

The  quartz  is  followed  by  prelinite  in  broad  surfaces  of  large  crystals, 
simple  or  slightly  rosetted.  The  prehnite  was  followed  by  laumontite  in 
fine  large  crystals  possessing  the  wholly  peculiar  form  characteristic  of  this 
mineral,  but  now  represented  only  by  hollow  incrustation  pseudomorphs  in 
albite,  which  latter  appear  as  minute,  limpid,  very  characteristic  twins.  The 
whole  forms  thus  a  very  peculiar  but  very  clearly  observed  pai-agenesis. 

Bussell. — Mineral  veins  appear  in  the  northwest  part  of  Russell,  show- 
ing drusy  quartz  and  galena.'  Specimens  are  deposited  in  the  Massachusetts 
State  Survey  collection  made  by  E.  Hitchcock. 

Huntington. —  Angel's  mine,  Norwich,  now  Huntington.  Showing 
blende  in  large  masses  and  a  beautiful  drusy  quartz  pseudomorph  after 
barite  and  calcite,^  according  to  the  specimens  in  the  survey  collection. 

iCat.  Agr.  Museum,  1859.     Rept.  Agriculture  Mass.,  Appendix,  p.  LXIX,  No.  XIX,  202,  203. 
« Loo.  cit.,  200,  201, 204-211. 


CHAPTER    XV. 
THE    PLEISTOCENE    PERIOD. 

LITERATURE. 

1818.  B.  Hitchcock.    Geology  of  Deerfield.    Am.  Jour.  Sci.,  1st  series,  Vol.  II, 
p.  107. 

1823.  ,    Geology  of  Connecticut  River.    Ibid.,  Vol.  VI,  p.  80. 

1827.  A.  If  ash.    Lead  Mipes,  etc.,  of  Hampshire  County.    Ibid.,  Vol.  XII,  p.  248, 

1833.  E.  Hitchcock.    Geology  of  Massachusetts,  pp.  33, 135. 

1835.  .    Geology  of  Massachusetts,  2d  edition,  p.  174. 

1841.  .     Geology  of  Massachusetts,  Final  Eeport,  i°,  pp.  306,  332,  357. 

1850.  .    Proc.  Am.  Assoc.  Adv.  Sci.,  Vol.  Ill,  p.  155. 

1852.  .    Ibid.,  Vol.  VI,  p.  264. 

I860.  .    Illustrations  of  Surface  Geology.    Smithsonian  Contributions  to 

Knowledge,  Vol.  IX,  pp.  1-155.    Also  issued  separately. 

1863.  .     Reminiscences  of  Amherst  College,  pp.  260,  311. 

1871.  J.  D.  Dana.    On  the  Connecticut  River  Valley  Glacier.    Am.  Jour.  Sci., 
'  3d  series.  Vol.  II,  p.  233.    Vol.  V^1873,  pp.  198,  217.    Vol.  X,  1875,  pp. 
180,  280,  353,  497.     Vol.  XII,  1876,  p.  125.     Vol.  XXIII,  1882,  p.  87. 
Vol.  XXV,  1883,  p.  440.     Also  published  separately. 

1877.  J.  S.  Diller.    Westfleld  during  the  Champlain  Period.    Am.  Jour.  Sci.,  3d 
series,  Vol.  XIII,  p.  262. 

1877.  .    Westfleld  Times  and  News  Letter,  Vol.  XXXVII,  March  28,  Sep- 
tember 19. 

THE  INTERVAL  BETWEEN  THE  TRIASSIC  AND  THE  GLACIAL  PERIOD. 

DEPOSITS. 

Within  tlie  area  here  under  survey  the  materials  for  a  reconstruction 
of  the  history  of  the  later  Mesozoic  and  the  Tertiary  are  extremely  scanty. 

With  the  exception  of  a  single  trap  talus  beneath  the  lower  till  there 
are  no  known  deposits  left  to  represent  these  long  ages.  The  excavations 
for  the  Turners  Falls  branch  of  the  Canal  Railroad  were  earned  along  the 
south  side  of  the  Deerfield  River  where  the  latter  passes  through  the  notch 
in  the  Deei-field  range  to  reach  the  Connecticut,  and  exposed  at  a  height  of 

508 


PKE-GLACIAL  CONDITIONS.  5()9 

50  feet  above  the  river  a  great  talus  of  trap  fragments — a  pre-Glacial 
"Devils  Garden,"  as  these  desolate  slopes  were  called  by  the  fathers — 
resting  against  the  vertical  wall  of  trap,  which  here  rises  about  100  feet 
above  the  level  of  the  stream.  The  talus  was  exposed  for  a  length  of  90 
feet  and  for  a  height  of  30  feet,  and  it  apparently  extends  down  to  the 
level  of  the  river,  50  feet  below,  but  this  was  not  observed.  Covering  this 
talus  and  extending  up  over  the  trap  was  a  layer  of  very  compact  till,  30 
feet  thick,  of  reddish  color,  made  up  mostly  of  sandstone  with  few  bowlders 
of  mica-schist  from  the  western  hills  and  with  none  of  trap.  At  least  nine- 
tenths  of  the  bowlders,  down  to  those  not  above  2  inches  on  a  side,  were 
finely  striated — a  quite  unusual  proportion. 

A  fresh  vertical  section  of  this  till  produced  by  caving  was  marked  for 
a  long  distance  by  wavy  lines  of  apparent  bedding  so  perfect  that  at  a  dis- 
tance I  had  supposed  the  beds  to  be  the  thin-laminated  Champlain  clays, 
but  the  lamination  proved  to  be  an  unusually  perfect  pressure  cleavage  in 
the  till,  in  planes  dipping  60°  to  70°  NW.,  at  right  angles  to  the  direction 
from  which  the  ice  was  moving  in  the  canyon,  as  marked  by  the  striae 
upon  the  trap  immediately  above.  These  data  prove  that  the  ice  breasting 
the  long  westward-facing  vertical  wall  of  the  Deei-field  trap  range  was 
pressed  into  this  notch  in  the  range  with  exceptional  force,  from  which  we 
may  deduce  that  the  prevalent  southward  motion  of  the  ice  in  the  valley 
was  due  to  its  deflection  from  the  normal  northeast  direction  by  the  north- 
south  walls  of  the  valley  and  of  the  divide  ranges. 

A  further  interesting  deduction  is  that  the  notch  of  the  Deerfield  range 
is,  in  its  present  form,  of  pre-Glacial  origin,  and  since  the  river  flows 
through  without  exposing  rock  at  bottom  the  gorge  was  then  of  even  greater 
depth  than  at  present.  The  Deerfield  Indians  aflirmed  that  it  was  begun 
by  a  squaw  with  a  clam  shell. 

One  other  deposit,  probably  of  Tertiary  age,  is  described  with  the 
"Camp  Meeting  cutting,"  near  end  of  Chapter  XIX.  It  is  a  thoroughly 
sorted,  pink  beach  sand,  and  it  appears  below  the  glacial  beds  on  the  north 
line  of  Northampton. 

PRE-GLACIAL  WEATHERING. 

The  only  important  case  of  the  preservation  of  any  portion  of  the 
deeply  decomposed  surface  rocks  which  must  have  characterized  the 
country  before  the  advent  of  the  ice,  as  they  are  now  characteristic  of 


510  GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

non-glaciated  countries,  is  the  great  bed  of  kaolin  preserved  from  the  ice 
under  the  lee  of  the  great  hill  on  which  Blandford  is  built  (see  p.  330). 
Another  area  is  northwest  of  Roaring  Brook  bridge,  on  the  south  line  of 
Northampton  (p.  474). 

PRE-GLACIAL  DRAINAGE  AND   EROSION. 

The  above  deduction  concerning  the  age  of  the  Deerfield  notch  may 
serve  as  an  introduction  to  the  discussion  of  the  other  similar  notches  in  the 
valley  and  of  its  pre-Glacial  drainage  and  erosion.  (See  map,  PI.  XI.) 
Not  only  does  the  Connecticut  pass  tlii'ough  a  like  notch  in  the  Holyoke 
trap  range  near  its  highest  point  in  a  deep,  short  valley  bordered  by  fine 
rock-cut  terraces  (fig.  28),  while  it  could  have  passed  down  the  western 
lateral  valley  (see  topography  of  the  valley,  p.  8)  without  rising  more  than 
145  feet  above  its  present  height,  but  the  Westfield  and  Farmington  rivers 
also,  like  the  Deerfield,  after  passing  out  of  their  gorges  in  the  crystalline 
rocks,  run  across  the  low  sand  plains  of  the  western  lateral  valley,  make  a 


Fig.  28.— Holyoke  notch  from  Hadley  meadow ;  pre-Glacial  rock  terraces. 

wide  loop  southward,  and  return  to  find  in  each  case  opposite  the  mouths 
of  these  gorges  a  notch  in  the  high  trap  ridge  through  which  they  join  the 
main  stream,  while  in  each  case  they  could  with  a  sHght  rise  have  passed 
southwardly  across  the  sand  plains,  the  Deerfield  to  join  the  Connecticut 
around  the  south  of  Sugar  Loaf,  the  others  to  reach  the  Sound  at  New 
Haven.  Indeed,  this  peculiarity  of  the  valley  system  of  the  Connecticut 
early  attracted  the  attention  of  President  Hitchcock,  who,  after  having 
described  it  with  a  sketch  map  in  the  Geology  of  the  Connecticut,^  writes 
in  the  Greology  of  Massachusetts  (1841,  p.  328): 

The  valleys  through  which  the  Connecticut  and  its  tributaries  flow  are  among 
the  most  remarkable  in  the  State.  The  ordinary  laws  of  physical  geography  seem 
here  to  be  set  at  defiance,  so  much  that  a  late  ingenious  writer  doubted  whether  I 
had  correctly  represented  the  geology  of  the  Connecticut  because  the  course  of 
the  rivers  and  the  direction  of  the  mountain  ridges  were  described  as  having  so 
little  correspondence  with  the  rock  formations. 

'  Am.  Jour.  Sci.,  Ist  series,  Vol.  VI,  1823,  p.  1. 


11 


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PUE  GLACIAL  DRAINAGE  AND  EROSION.  511 

President  Hitchcock  draws  the  inference  from  the  facts  detailed  above 
"that  the  Connectictit  River  did  not  excavate  its  own  bed  through  these 
mountains,  for  liad  the  bamer  at  Northampton  been  more  than  134  feet 
above  its  present  bed  it  must  have  emptied  into  the  Sound  at  New  Haven. 
We  nuist  seek  some  other  cause,  therefore,  for  the  origin  of  the  passage 
between  Holyoke  and  Mount  Tom."  I  draw  the  opposite  conclusion,  and 
belie\e  the  history  of  the  erosion  of  the  valley  to  have  been  as  follows: 

The  streams  occupied  their  present  valleys  in  the  crystalline  rocks 
before  and  during  the  Triassic  (at  levels,  of  course,  much  higher  than  the 
present),  and  entered  the  Triassic  estuary  near  where  their  gorges  now 
end  at  the  border  of  the  sandstone.  On  the  recession  of  the  waters  the 
Connecticut  followed  down  the  deepest  line  in  the  middle  of  the  long 
bay  and  the  tributaries  took  a  dii-ect  course  down  the  slope  to  this  line 
of  greatest  depth  to  join  the  main  river. 

I  imagine  that  the  dislocation  of  the  sandstones  took  place  after  this 
drainage  was  established,  and  so  slowly  that  the  streams  were  not  seriously 
disturbed,  but  cut  down  through  the  sandstones  till  they  reached  the  trap 
sheets,  and  then  through  these  until  the  four  gorges  were  carved. 

Many  facts  point  to  the  conclusion  that  these  valleys  were  cut  much 
deeper  than  the  present  bed  of  the  river,  and  down,  indeed,  to  or  below  the 
present  level  of  the  sea.  Piles  driven  in  clay  at  the  Northampton  bridge 
went  10  feet  below  sea  level.  The  Belden  artesian  well,  south  of  the  North- 
ampton station,  struck  rock  25  feet  below  sea  level,  and  soundings  showed 
the  clays  to  have  great  depth  beneath  the  main  street  crossing;  these  may 
represent  an  old  course  of  the  Mill  River.  Borings  of  the  United  States 
survey  of  the  Connecticut  River  between  Chicopee  and  Longmeadow  were 
can-ied  to  points  19  and  21  feet  above  sea  level  and  43  feet  below  without 
meeting  rock,  and  1^  feet  above  sea  level  striking  rock.-'  In  each  of  the 
four  gorges  here  specially  under  discussion  no  rock  appears  in  the  stream 
beds.  All  the  points  cited  above  lie  along  the  old  channel,  at  places 
specially  sheltered  from  glacial  erosion. 

From  this  one  may  conclude,  in  passing,  that  the  falls  along  the  Con- 
necticut are  located  in  portions  of  its  course  which  do  not  coincide  with 
this  ancient  one. 

•T.  G.  Ellis,  Report  of  survey  of  Connecticut  River:  Ex.  Doc.  101,  Forty-fifth  Congress,  second 
session,  1878,  p.  122. 


512       GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

Parallel  with  this  deepening  of  the  stream  beds  the  unequal  erosion  of 
the  whole  area  wore  back  the  banks  of  the  streams  in  easy  slopes  where 
they  crossed  the  soft  sandstones,  brought  out  the  trap  ridges  in  sharp  relief, 
and  left  thus  the  short  canyons  or  notches  through  these  ridges. 

Thus  on  the  approach  of  the  Glacial  period  a  surface  had  been  reached 
which  coincided  much  more  closely  with  the  present  cultivated  surface  of 
the  valley  than  with  its  present  rocky  floor,  except  along  the  western  lateral 
valley — that  is,  the  broad  depression  west  of  the  trap  ranges — and  north  of 
the  Holyoke  range,  where  the  surface  of  the  sandstones  was  then  probably 
higher  than  the  present  surface  of  the  later  sands.  Then  came  the  Glacial 
ice,  destroying  the  whole  drainage  system  and  removing  an  enormous 
quantity  of  the  soft  sandstone.  Its  work  was  favored  and  localized  in  two 
Avays  by  the  position  of  the  trap  ranges  running  down  the  middle  of  the 
valley.  Where  these  ran  north  and  south  with  bold  westward-facing  bluffs, 
as  in  the  Deerfield  and  Mount  Tom  ranges,  the  ice  coming  from  the  north- 
west was  deflected  southward  and  scoured  out  the  soft  sandstone  at  the 
western  foot  of  these  ranges,  and  where  the  Holyoke  range  runs  clear 
athwart  the  valley  east  and  west  the  ice,  by  its  recoil  as  it  lifted  over  the 
range,  plowed  out  the  sandstone  all  along  its  northern  base  down  to  a  level 
much  lower  than  could  have  been  well  effected  by  ordinary  aqueous  erosion- 

Thus  the  river  channels  between  the  ends  of  the  ravines  in  the  crystal- 
line rocks  and  the  notches  in  the  trap  ridges  were  obliterated  because  they 
were  contained  in  the  comparatively  soft  sandstone,  and  we  have  finally  to 
seek  the  reason  why  the  streams,  upon  the  decrease  of  the  floods  which 
accompanied  the  retreat  of  the  ice,  in  every  case  found  their  way  again 
through  their  old  notches  instead  of  taking  the  more  direct  and  natural 
course  down  the  deep  western  lateral  valley,  from  which  the  ice  had  removed 
the  sandstone  to  so  low  a  level.  The  broad  river  occupied  then  almost 
precisely  the  boundaries  of  the  earlier  Triassic  estuary,  and  the  tributaries 
entered  it  along  the  border  of  the  western  highlands. 

Across  Massachusetts  the  great  river  was,  indeed,  rather  a  series  of  lakes 
than  a  river,  in  that  it  was  filled  mainly  from  the  sides  by  the  great  confluent 
deltas  of  its  tributaries,  which  were  pushed  out  to  a  distance  proportionate 
to  the  importance  of  the  stream  that  furnished  each,  while  down  its  center 
clays  and  fine  sands  were  deposited  in  less  thickness.  Thus  it  came  about 
that  the  great  body  of  sand  delivered  to  the  main  stream  by  each  tributary 
was  spread  diagonally  across  between  the  western  hills  and  the  divide  ranges, 


rKli-GLAOIAL  DRAINAGE  AND  EROSION.  513 

and  in  somevvhut  larger  proportions  in  the  area  just  below  the  mouth  of  the 
tributary  as  a  resultant  of  the  transporting  power  of  the  main  stream  and 
the  tributary,  so  that  upon  the  lowering  of  the  waters  of  the  mam  stream 
and  theii'  retreat  from  the  western  lateral  valley  each  tributary  found  its 
way  southward  dammed  up  by  its  own  delta  deposits,  and,  ponding  back 
behind  them,  flowed  again  through  its  old  notch  to  join  the  diminished 
waters  of  the  Comiecticut.  The  heavy  sands  which  fill  up  the  lateral  valley 
below  each  of  these  tributaries,  from  the  western  border  across  to  the  divide 
range,  do  in  fact  show,  both  by  the  derivation  of  their  material  and  by  their 
structure,  that  they  are  the  ancient  deltas  of  these  streams. 

The  thread  of  the  current  of  the  main  stream,  driven  clear  across  toward 
the  eastern  foot  of  the  divide  range  by  the  great  delta  of  the  Millers  and 
Chicopee  rivers,  had  continued  to  pass  through  (a)  the  narrow  passage 
between  Deei-field  Mountain  and  Mount  Toby  and  (h)  the  Holyoke  notch, 
two  portions  of  its  old  channel,  partly,  perhaps,  because  these  lay  in  the 
main  artery  of  the  pre-Glacial  drainage,  but  more  because  they  were  out 
in  the  center  of  the  lake,  far  from  all  lateral  streams  and  their  deposits,  and 
on  the  recession  of  the  waters  the  western  or  lateral  valley  was  filled  up 
to  such  a  height  by  the  Westfield  River  that  the  Connecticut  was  compelled 
to  shrink  down  to  this  line  and  reoccupy  its  old  notch  in  the  Holyoke  range. 

THE   PRE-GLACIAL   COURSE   OF   THE   CONNECTICUT  AND   ITS    TRIBUTARIES. 

The  pre-Glacial  bed  of  the  Connecticut  across  Massachusetts  lay 
below  the  present  sea  level.  (See  map,  PI.  XI,  p.  510.)  Hence,  where 
the  river  passes  over  rocky  bottonis  with  rapids  and  waterfalls  it  has  been 
expelled  from  its  pre-Glacial  bed  by  Glacial  and  Champlain  deposits.  In 
each  case  the  old  bed  of  the  stream  is  marked  by  a  broad  band  of  depres- 
sions in  the  high  terrace  sands — kettleholes — partly  empty  and  partly 
water-filled.  The  ice  seems  to  have  persisted  in  the  deep  channel  until  it 
was  covered  by  the  flood  sands  and  then  to  have  melted  to  form  the 
depressions.  This  is  most  marked  south  of  Millers  Falls  across  the  Mon- 
tague plain,  in  the  great'  loop  of  Millers  River  and  the  succession  of  ponds 
extending  southward,  of  which  Lake  Pleasant  (its  bottom  about  67  feet 
below  the  plain)  is  the  largest.  From  the  State  line  to  Northfield  farms 
the  river  has  regained  its  old  bed.  South  of  this  point  the  great  delta  of 
Millers  River  crowded  it  6  miles  west  to  the  foot  of  the  trap  ridge  and 
MON  xxis 33 


6i4  GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

compelled  it  to  cut  in  tlie  sandstone  the  French  King  gorge^  and  the  canyon 
of  the  Lily  Pond. 

The  river  regains  its  old  bed  in  the  passage  between  Mount  Toby  and 
Sugar  Loaf,  where  its  fine  pre-Glacial  rock-cut  terraces  which  flank  Mount 
Toby  have  received  the  name  Sunderland  Park,  and  its  course  across  the 
Hatfield-Northampton  meadows  is  closely  given  on  PL  XI,  p.  510.  After 
its  passage  through  the  Holyoke  notch  its  course  is  uncertain,  and  there  I 
give  two  alternatives  on  the  map. 

The  reasons  favoring  the  eastern  course  are  that  it  lies  along  a  line  of 
deep  depressions  in  the  broad  sand  plain,  and  shows  no  rock  outcrops  where 
erosion  has  gone  deepest.  The  reasons  favoring  the  other  course  are  that 
it  passes  over  the  borings  of  the  Grovernment  surveys  of  the  Connecticut 
River,  one  of  which  went  30  to  40  feet  below  sea  level,  and,  like  the  other, 
is  a  line  where  the  deepest  erosion  discloses  no  rock.  (See  "The  Spring- 
field Lake,"  in  Chapter  XIX. 

It  is  certain  that  between  the  Holyoke  notch  and  the  latitude  of 
Springfield  the  river  ran  far  east  of  its  present  course,  because  it  now 
cuts  tlu'ough  rock  all  the  way  from  Mount  Holyoke  to  the  Holyoke  Falls. 

The  justification  for  the  course  given  the  Deerfield  River  and  the 
Westfield  River  has  been  presented  above.  An  inspection  of  the  map  will 
suggest  that  the  Deerfield  River  may  have  run  southeast  from  its  ravine 
through  the  finely  rock-terraced  notch  between  Sugar  Loaf  and  North 
Sugar  Loaf,  and  that  its  present  notch  in  this  range  may  have  been  cut  by 
the  Grreen  River,  but  the  drawing  on  the  map  represents  the  most  pi'obable 
status.  The  Sugar  Loaf  notch  is  not  deep  enough  for  the  Deerfield  River, 
which  probably  ran  south  of  Sugar  Loaf. 

The  notch  which  separates  Sugar  Loaf  from  North  Sugar  Loaf  is  plainly 
water-formed,  and  Whately  Glen  is  its  most  probable  upstream  continuation 
among  the  crystalline  rocks,  as  indicated  on  the  map. 

In  the  same  way  the  main  gap  in  the  center  of  the  Holyoke  range,  to 
which  the  name  "Notch"  is  especially  I'estricted  in  the  valley,  was  the 
result  of  water  erosion  and  was  the  site  of  a  great  waterfall  before  the 
Glacial  period.  It  is  deeply  cut  in  the  trap,  with  vertical  walls,  and  its 
continuation  in  the  sandstone  immediately  south  of  the  trap  sinks  very 
suddenly  to  a  much  lower  level,  forming  the  Orchid  Garden,  celebrated 
among  botanists.     I  think  this  notch  was  in  continuation  of  the  "Freshman 

'  See  footnote  on  pnge  296. 


PRE-GLACIAL  EROSION.  515 

River."  It  was  temporarily  reoccupieil  duriiii^'  the  recession  of  the  ice, 
recei\iu<>-  the  overflow  of"  a  Glacial  lake  which  formed  ou  the  north  flank  of 
the  Holyoke  range,  banked  on  the  north  by  the  ice  of  the  Hadley  basin. 

There  are  two  striking  gorges  in  tlie  west  of  the  town  of  Holyoke, 
both  cutting  the  trap  very  obliquely,  one  occupied  by  Wrights  Brook 
(which  enters  Hitchcocks  Pond),  while  the  Westfield  and  Holyoke  Rail- 
road passes  through  the  other.  These  gorges  seem  to  be  portions  of  the 
bed  of  a  stream  that  gathered  on  the  east  flank  of  Mount  Tom  and  ran 
south  into  the  Westfield  River. 

Another  notch  of  unknown  depth  cuts  the  trap  ridge  just  where  it 
crosses  the  State  line  into  Connecticut.  This  I  have  connected  with  the 
large  brook  which  comes  down  from  Sodom  Mountain,  in  Granville,  and 
have  called  it  on  the  map  the  Southwick  notch. 

Though  the  evidence  is  much  less  clear,  it  seems  probable  that  the 
narrow  canyon  skirting  the  east  front  of  Mount  Toby  was  cut  by  Locks 
Brook.  Its  bottom  has  now  the  shape  of  an  abandoned  water  channel.  It 
is  probable  that  the  portion  of  the  channel  of  Locks  Brook  which  ran  in 
sandstone  between  the  end  of  its  gorge  in  the  crystalline  rocks  and  the 
beginning  of  the  canyon  was  removed  b)^  ice  erosion.  At  the  end  of  the 
Glacial  period  the  ice,  halting  in  the  Montague  basin,  deflected  the  brook 
again  southward  into  this  canyon. 

THE  CHARACTER  AND  AMOUNT  OF    EROSION    DURING    LATER  MESOZOIC  TIME 
AS  COMPARED  WITH  THAT  OF  THE  GLACIAL  PERIOD. 

From  the  preceding  discussions  of  the  crystalline  rocks  and  the  Tri- 
assic  sandstones  it  is  certain  that  the  broad  Connecticut  Valley  was  an 
orographic  feature  of  first  importance  formed  in  the  crystalline  rocks  before 
the  deposition  of  the  sandstones,  its  borders  coinciding  closely  with  the 
present  boundaries  of  the  latter.  Prof  W.  M.  Davis^  has  suggested  that 
there  may  have  been  a  pre-Triassic  penei^lain  over  this  area.  The  places 
where  the  crystalline  rocks  break  through  the  Trias  are  at  such  different 
levels  in  places  very  near  one  another  that  this  is  not  probable. 

This  valley  was  then  deeply  filled  by  the  sands  of  the  Trias,  indeed 
above  and  beyond  the  present  lips  of  the  basin,  and  has  been  since  so  thor- 
oughly eroded  a  second  time  that  only  remnants  of  this  filling  remain.  It 
seems  quite  certain,  that  the  walls  of  the  valley  during  and  at  the  close 


1  Bull.  Geol.  Soc.  America,  Vol.  II,  p,  549.     .Jour.  Geol.,  Vol.  IV,  p.  678. 


516  GEOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 

of  the  Trias  were  much  higher  than  now  or  that  the  sandstones  once 
extended  much  farther  east  and  west. 

Mount  Toby,  wholly  made  up  of  sandstone  and  conglomerate,  is  1,275 
feet  above  sea  level  (1,170  feet  above  the  river),  but  to  obtain  its  true 
height  as  a  measure  of  the  height  of  the  Triassic  at  its  maximum  we  must 
add  a  considerable  but  unknown  amount  for  subaerial  and  glacial  erosion. 
It  is  possible  that  we  must  subtract  something  also  to  offset  the  elevation  of 
the  mass  during  the  disturbances  which  have  tilted  the  rocks.  I  imagine 
it  would  be  an  overestimate  of  the  latter  movement  if  we  should  assume  it 
to  have  been  great  enough  to  counterbalance  the  depression  of  the  old  sur- 
face by  erosion.  If,  then,  we  take  the  present  height  of  Mount  Toby  or 
Mount  Tom  as  that  of  the  sandstone  at  the  close  of  its  deposition  and  run 
a  contour  line  at  this  level  along  the  sides  of  the  valley  to  obtain  the  orig- 
inal boundaries  of  the  sandstones,  on  the  assumption  that  the  valley  walls 
were  then  about  their  present  height,  this  line  would  lie  so  far  back  from 
the  present  border  of  the  sandstone  and  run  into  so  many  sheltered  valleys 
that  we  should  encounter  greater  difficulty  in  explaining  why  the  sandstones 
are  wholly  absent  from  these  broad  areas  on  each  side  of  their  present 
limits  than  in  assuming  a  very  considerable  degradation  of  the  walls  of  the 
valley  since  it  served  as  an  estuary  for  the  accumulation  of  the  Triassic 
sediments.  Indeed,  we  may  say  directly  that  the  present  border  of  the 
sandstones  represents  closely  the  old  border  of  the  estuary,  because  the 
coarse  angular  conglomerates  and  rudely  sorted  feldspathic  sandstones  can 
have  been  transported  but  a  very  short  distance,  and,  as  their  mineralogical 
character  indicates,  must  have  been  derived  largely  from  beds  immediately 
adjacent,  which  would  have  been  covered  if  the  waters  of  the  estuary  had 
extended  as  far  as  the  supposed  contour  line,  and  that,  therefore,  the  crys- 
talline border  of  the  valley  must  have  been  sufficiently  higher  than  now  to 
form  retaining  walls  for  the  accumulated  Triassic  gravels.  Within  these 
limits  the  coarse  sandstone  rose,  as  above  indicated,  to  a  height  above  that 
of  Mount  Toby,  filling  the  whole  valley  to  that  level.  The  increased  ele- 
vation may  have  amounted  to  many  hundred  feet. 

It  would  be  interesting  to  follow  the  course  of  the  erosion  by  which  the 
present  ridges  have  been  sculptured  out  of  this  mass  and  to  divide  the  long 
quiet  work  of  the  waters  in  later  Mesozoic  and  Tertiary  times  from  the  work 
of  the  harsher  agencies  of  the  Glacial  period. 


PRE-GLACIAL  EEOSION.  517 

I  think  it  nvAy  be  deduced  from  the  facts  given  above  that  the  greater 
portion  of  this  erosion  was  performed  by  the  first  agent,  but  that  the  ice 
wore  into  the  soft  sandstone  considerably,  and  in  some  places  enormously; 
so  that,  if  the  Pleistocene  deposits  were  removed  from  the  valley,  the  rocky 
floor  below  would  bear  small  resemblance  to  the  surface  upon  which  the  ice 
be"-an  to  act.  I  imagine  that  the  present  surface  of  these  latter  deposits 
would  much  more  nearly  coincide  therewith.  Indeed,  along  all  the  west 
side  of  the  valley  f)"om  Deerfield  to  Southwick  and  beyond,  and  north 
of  the  Holyoke  range,  the  sandstones  may  well  have  been  considerably 
higher  than  the  present  cultivated  surface  of  the  valley.  This  is  deduced 
from  the  consideration  that  if  the  present  drainage  represents  closely  the 
pre-Glacial,  as  shown  above,  the  sandstone  should  rise  by  easy  slopes  from 
the  streams  and  be  highest  in  the  areas  between  them,  or  in  some  way  show 
an  intelligible  relation  to  them.  But  from  this  point  of  view  the  deep 
depression  in  the  sandstone  west  of  the  trap  ridge  in  Deerfield  and  north 
and  west  of  the  Holyoke  range  would  render  such  a  drainage  impossible, 
and  must  be  a  later  work,  which  can  only  have  been  done  by  the  ice.  This 
exceptional  erosion  of  the  ice  depended  largely  upon  the  soft  nature  of  the 
sandstones  and  the  peculiar  position  of  the  trap  ridges. 

From  the  top  of  Mount  Holyoke  I  have  seen  the  valley  fog  rest 
against  the  hiUs  east  and  west  and,  rising  to  my  feet,  spread,  with  a  surface 
level  as  the  sea,  up  and  down  the  valley  as  far  as  the  eye  could  reach.  If 
it  had  risen  a  few  hundred  feet  higher  I  believe  its  mass  would  have 
rudely  equaled  the  pre-Glacial  erosion  of  the  Triassic,  while  I  imagine  the 
present  Pleistocene  deposits  in  the  valley  would  scarcely  equal  the  amount 
removed  by  the  ice. 

As  for  the  crystalline  rocks  which  flank  the  broad  Connecticut  Valley 
on  either  side,  the  fact  that  the  newer  crystallines  are  covered  by  the  Trias 
in  the  bottom  of  the  valley  and  yet  are  abundantly  present  in  the  coarse 
Triassic  conglomerates,  while  the  older  Cambrian  gneisses  are  broadly 
exposed  on  the  east  but  are  not  represented  in  the  adjoining  Triassic  con- 
glomerates, shows  that  there  has  been  large  erosion  over  the  eastern  plateau 
since  the  Trias.  The  suggestion  of  Professor  Pumpelly  that  secular  disin- 
tegration may  have  deeply  prepared  these  rocks  for  glacial  erosion  must 
be  taken  account  of,  and  renders  it  impossible  to  assign  to  pre-Glacial  and 
Glacial  agencies  their  proper  share  of  work. 


CHAPTER   XVI. 
THE    GLACIAL   PERIOD. 

THE   PRESENT   ROCK   SURFACE  AND   THE  AMOUNT    OF   GLACIAE  AND 
POST-GLACIAL  MATERIAL   ON  THE  SAME. 

If  the  unconsolidated  deposits — sands,  clays,  and  gravels — ^were 
removed  from  tlie  valley  we  should  see  a  rocky  floor,  everywhere  almost 
the  exact  surface  upon  which  the  ice  last  lay,  except  where,  from  the  north- 
ward-facing cliffs  of  the  Holyoke  range,  the  frosts  have  since  eaten  into  the 
much  fissured  trap  and  formed  the  talus  of  sharp  fragments  which  rests 
against  its  base,  and  in  limited  areas  where  the  streams  flow  on  rocky  beds. 

The  whole  horizon  would  be  unchanged.  The  high  ridge  which  stretches 
south  from  Mount  Toby,  and  upon  which  North  Amherst,  Amherst  village, 
and  South  Amherst  are  built,  would  be  little  changed  until,  coming  south- 
ward, we  reached  Mount  Pleasant,  the  southern  portion  of  which  would  be 
lowered  to  the  level  of  the  street  at  its  western  base,  and  College  Hill, 
Mount  Doma,  and  Castor  and  Pollux^  would  also  be  absent.  A  ridge  of 
rock  woiTld  also  stretch  southward  from  Mount  Warner,  much  below  the 
present  surface.  The  three  depressions  which,  running  noi'th  and  south, 
bound  these  two  ridges,  would  be  much  deepened,  the  East  street  depression 
by  at  least  50  feet;  the  middle  one,  separating  the  two  rocky  ridges,  to  an 
unknown  depth ;  the  western,  in  which  the  Connecticut  now  rmis,  to  at  least 
110  feet  below  low  water  of  that  river,  and  thus  down  somewhat  below 
the  level  of  the  sea.  On  the  west  of  the  river,  in  Northampton,  the  changes 
would  be  more  extensive,  as  south  of  Elizabeth  Rock  and  Roberts  Hills  and 
east  of  Loudville  all  the  elevated  country.  Round  Hill,  the  Hospital  Hill,  and 
the  rest,  would  be  removed,  and  the  rock  floor  would  be  found  everywhere 
down  near  or  below  the  present  level  of  the  river,  except  along  Mill  River 
near  the  West  street  bridge.  Under  the  Northampton  meadows  it  may 
well  be  a  hundred  feet  below  the  river  level.  I  have  already  indicated 
the  probable  condition  of  the  valley  when  the  ice  began  to  work  upon  it. 


'  Names  given  Ijy  President  Hitchcock  to  drumlins  south  of  College  Grove  and  north  and  south 
of  South  Amherst. 
.518 


THE  PRESENT  KOCK  SUIiFAOE.  519 

ard  the  cause  of  the  extreme  inequality  of  its  effects  over  difiPereut  portious 
of  the  basin  is  to  be  found  primarily  in  the  unequal  resistance  offered  by 
the  different  rocks  of  which  it  is  (composed,  and  secondarily  in  the  influence 
of  the  i)rojecting  masses  of  harder  rock  in  deflecting  the  ice  and  shielding- 
the  softer  rocks  in  their  lee.  Here  the  trap,  so  easily  dissected  by  the 
frost,  proved  most  able  to  resist  the  onset  of  the  ice.  The  ridge  of  trap 
which  makes  the  backbone  of  Deerfield  Mountain  survived  after  the  sand- 
stone had  been  worn  down  on  either  side  and  protected  the  Sugar  Loaf  ^  in 
its  lee,  and,  with  Mount  Warner,  farther  south,  projected  into  the  ice  as  it 
wore  dee})ly  on  their  flanks.  So  Mount  Toby,  built  of  a  conglomerate 
more  durable  than  the  sandstone  beneath,  and  protected  by  Deerfield 
Mountain,  stemmed  the  ice  and  sheltered  the  long  ridge  which  runs  south 
from  it,  so  far  that  a  fragment  of  the  soft  incoherent  sandstone  still  lies 
along  its  eastern  slope  in  Amherst  village. 

But  the  Holyoke  range,  coming  up  from  the  south,  swings  around 
eastward  in  a  great  curve,  commencing  at  Mount  Tom,  and  from  Mount 
Holyoke  on  runs  eastward  to  its  end,  and  the  great  trap  sheet  which 
makes  its  strength  is  so  placed  as  to  present  the  maximum  resistance  to 
the  ice  moving  from  the  north  and  northwest — that  is,  it  dips  every- 
where as  a  continuous  sheet  from  the  crest  of  the  ridge  southward  where 
the  chain  runs  east  and  west,  and  as  the  ridge  swings  round  to  run  south- 
ward the  dip  of  the  sheet  swings  round  to  the  east.  It  received  the 
pressure  of  the  ice,  then,  as  a  log  set  to  brace  a  falling  building  receives 
its  weight.  The  ice,  lifting  over  this  sharp  obstruction  set  right  athwart 
its  course,  wore  into  it  with  great  severity,  and  by  its  recoil  as  it  raised 
its  mass  over  the  opposing  range  wore  to  a  very  exceptional  depth  in  the 
area  just  in  front  of  the  latter,  which  had  been  filled  with  the  soft  sand- 
stone, forming  the  broad,  deep  furrow  which  runs  along  the  northern  and 
western  base  of  the  range,  beneath  the  Easthampton,  Northampton,  and 
Hadley  meadows,  and  in  the  southern  part  of  Amherst,  in  which  furrow 
the  tlu'ee    deep  north-south  depressions  I  have  described    above  ended.^ 


'  The  table-moantain  form  of  Sugar  Loaf  is  probably  due  to  a  capping  of  trap  from  the  southward 
projection  of  the  Deerfield  trap  sheet,  ■which  endured  to  near  the  close  of  the  Glacial  period.  It  is  called 
an  "Eddy  Peak "  by  Prof.  J.  D.  Whitney  (1888) ;  see  bibliography  in  Chapter  XXIII. 

=  It  is  an  interesting  fact  that  a  line  at  the  north  foot  of  the  east  end  of  the  Holyoke  range 
forms  a  boundary  north  of  which  granite  bowlders  are  abundant  in  the  till,  while  south  of  this  line 
they  are  rare.  This  is  because  the  ice  mass  was  greatly  shattered  as  it  lifted  over  the  ridge,  drop- 
ping its  bowlders,  while  it  eroded  strongly  on  the  crest;  or  it  may  represent  the  closing  period  when 
the  ice  wore  over  the  Leverett  granite  and  halted  at  the  north  foot  of  the  Holyoke  range. 


520  GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

It  would  be  tedious  to  detail  all  the  observations  upon  which  this  descrip- 
tion of  the  present  surface  of  the  rocky  substratum  of  the  valley  is  based. 
One  may  trace  on  the  map  the  crystalline  rocks  emerging  from  below  the 
sandstones  of  Mount  Toby  and  appearing  at  the  surface  in  scattered  out- 
crops southward  to  South  Amherst,  and  the  same  thing  may  be  seen, 
though  less  clearly,  south  of  Mount  Warner.  At  East  street  a  well  50 
feet  below  the  lowest  ground  there  failed  to  reach  the  ledge,  and  at  the 
Northampton  bridge  piles  were  driven  in  the  clays  110  feet  below  low 
water  of  the  river  without  reaching  bottom. 

The  most  remarkable  effect  upon  the  present  contour  of  the  basin  of 
this  general  erosion  of  the  ice  was  in  excavating  hollows  so  deep  and  capa- 
cious that — especially  where  they  lay  aside  from  the  direct  line  of  the  cur- 
rents of  the  floods  in  the  subsequent  period — they  have  remained  only 
partially  filled  to  the  present  time,  notably  in  the  case  of  the  East  street  val- 
ley and  the  southern  part  of  the  middle  depression,  which  lies  west  of  the 
village  of  South  Amherst. 

South  of  the  Holyoke  range  the  protecting  influence  of  the  ridge  is  as 
plainly  seen  as  its  agency  in  reenforcing  the  power  of  the  ice  on  its  north 
and  west,  and  the  sandstones  stand  much  higher  and  appear  abundantly 
above  the  surface  of  the  later  deposits  and  doubtless  make  a  continuous 
substratum  for  the  latter,  while  north  and  west,  I  imagine,  the  erosion 
over  much  of  the  deeply  covered  area  must  have  cut  down  through  the 
sandstones  to  the  crystalline  rocks  below. 

The  low  rock-floored  valley  bottom,  everywhere  nearly  at  and  often 
much  below  the  present  river  level,  stretching  across  from  the  Pelham  Hills 
to  the  western  line  of  Northampton  and  broken  only  by  the  Amherst  ridge 
and  Mount  Warner,  not  only  sent  a  lobe  southwardly  tlirough  Easthampton, 
but  another  of  exceptional  depth  up  through  the  Deerfield  Valley  to  the 
north  line  of  that  town,  which  was  continued  still  farther  north  in  a  strange, 
narrow  depression  running  up  the  west  side  of  Grreenfield  and  ending 
abruptly  at  its  north  line — a  depression  which  was  left  unfilled  in  Cham- 
plain  time. 

North  of  Mount  Toby  the  Montague  basin  would  be  also  largely 
increased  toward  the  north  by  the  removal  of  the  drift.  The  immense 
sand  desert  between  Millers  Falls  and  Turners  Falls  and  all  the  hills 
except  one  that  rise  above  it  would  be  removed,  leaving  a  great  depression, 


THE  PRESENT  ROCK  SURFACE.  521 

mucli  of  it,  l)elow  tlie  present  river  level,  with  an  old  bed  of  the  Connect- 
icnt  running-  down  its  middle  and  extending-  north  from  Millers  Falls  to 
the  State  line  with  considerable  increase  of  width.  And  the  removal  of 
the  great  swarm  of  drumlins  which  crowd  the  area  west  of  the  river 
in  the  northern  portion  of  its  course  would  materially  affect  the  contours 
in  Grill  and  Bemardston. 

On  the  higher  ground  west  of  the  valley  the  removal  of  the  loose 
deposits  would  not  so  materially  affect  the  surface  except  in  the  extreme 
west  of  Hampden  County,  and  especially  in  Blandford,  where  over  broad 
areas  the  till  reaches  great  thickness  and  rises  in  drumlins  of  the  first 
magnitude. 

East  of  the  Connecticut  Valley  the  same  remark  holds,  'except  for 
eastern  Hampden  and  southeastern  Hampshire,  where  the  removal  of  the 
heavy  sands  of  the  great  series  of  Glacial  lakes  described  beyond  would 
greatly  modify  the  surface  and  would  probably  show  the  deep  Greenwich- 
Enfield  Valley  to  be  continuous  across  Ware  and  thence,  via  the  Beaver 
Brook  and  Ware  River,  to  Thorndike,  and  thence  straight  south  to  Palmer 
station  and  on  through  the  deep  Monson.  Valley  and  the  narrow  gorge  of 
the  Willimantic  to  the  sea.  (See  map,  PL  XXXV.)  The  Ware  River  also 
seems  then  to  have  run  directly  south  to  Palmer  to  join  the  Swift  River. 

This  basin  stretching  from  Orange  south  across  the  State  to  its  south 
line  at  Monson  is  peculiar  in  many  ways.  It  is  underlain  by  the  Monson 
gneiss  and  widens  and  narrows  with  the  width  of  this  rock.  While  the 
broad  band  of  this  same  rock  which  lies  next  west  of  this  forms  high 
ground,  this  forms  a  deep  flat-bottomed  valley,  in  the  center  of  which  rise 
high,  isolated,  dome-shaped  hills  of  gneiss,  which  may  have  been  preserved 
by  a  capping  of  the  same  quartz  schists  which  form  the  high  walls  of  the 
basin.  The  whole  basin  seems  to  be  the  result  of  deep  disintegration  of 
the  gneiss. 


522 


GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 


GLACIAL   GROOVES  AND   STRI^. 

(See  map,  PI.  XI,  page  510.) 

List  of  glacial  grooves  and  strice  in  Franklin,  Hampshire,  and  Hampden  counties ; 

hearings  corrected. 

[E.H.  =  E.  Hitchcock,  Geology  of  Massachusetts,  1841,  p.  387;  Keport  on  Certain  Points  in  the  Geology  of  Massachu- 
setts, 1853,  House  Doo.  No.  39,  pp.  34-44.      B.  K.  E.  =  the  present  author.] 


Locality. 


Rock 


FEANKLIN  COUNTY. 

Kowe;  near  meetinghouse  and  in 

part. 
Rowe;  near  meetinghouse 


Eo-we;  north  part,  road  to  Whitingham, 
Vt. ;  spot  nearly  as  high  as  Hoosac 
Mountain. 


Heath ;  west  part . 


Heath;  near  center,  highland. 
Charleniont  Village 


Shelburne ;  northwest  part,  high  hill 

Bernardston ;  Williams  farm 

Northfleld;  Gill  station , 

Northfield ;  west  side  of  river  near  Hon. 
S.  C.  Allen's. 

Northfield ;  where  ferry  road  crosses  rail- 
road. 

Northfield ;  north  part  of  village 

Northfield;  north  of  commencement  of 
road  in  Big  Meadow. 

Northfield;  Beers  Plain 

Northfield ;  on  Strowbridge  Hill 

Northfield ;  southern  part  of  village 

Ashfield;  on  north  road  to  Goshen,  on 
hill  northeast  of  school. 

Ashfield;  G.  B.  Hall,  east  of  Ashfleld 
plains. 

Ashfield ;  east  of  Howsville 


Remarks. 


Sometimes  2  to  12  inches 
wide  and  several  deep. 

Sometimes  on  a  slope  of 
10°  southerly  imd  a  still 
greater  northerly  slope. 


The  last  but  one  cuts  the 
last. 

Frequent 


Authority. 


Mica  schist . 
Quartzite 
Gneiss. 
Hornblende  rook. 

Sandstone 


do  .- 

Granite . 


Mica-schist  — 
do 

Conglomerate. 
Mica- schist ... 


Conway  schist. 
do 


S.  5°  W. 


S.  10-12°  W. 
S.  10°  W... 


s.  10=  "w... 

S.  20°W.-. 

S.  8°E 

E 


Ashfield ;  south  of  South  Ashfleld do 

Greenfield ;  opposite  S.  Bullard's Sandstone  . 

Greenfield ;  low  down  on  the  trap  east  of  I  Trap 

Poets  Seat.  | 

Greenfield;  new  road  to  Gill do 

Greenfield;  200  feet  north  of  the  west  i do 

end  of  this  road. 

Greenfield ;  road  down  to  Riverside Sandstone  . 

Do do 


N.-S 

S.  10°  AV.. 
S.  30°  E... 
fS.5°E-... 
IS.  20°  W  . . 
S.40°'W  .. 
S.  30°  W . 
S.  5°  \7  . . . 


Parallel  with  valley  - 


Troughs  1  to  2  feet  wide- 
Distinct 


Arranged  in  order  of  age 
I    newest  above. 

In   valley   among   rugged 
hUls— first  entry  newer. 


S.  5°  "W  .  - 
S.  30°  "W" . 


S.  18°E. 
S.25°  E. 


Grooves  4  inches  wide. 


E.H. 

E.H. 

E.H. 

B.  K.  B. 

E.H. 
B.  K.E. 


E.H. 
B.  K.  E. 
B.  K.  E. 
E.H. 

B.  K.  E. 

B.  K.  E. 
B.K.E. 

B.  K.  E. 
B.  K.  E. 
E.H. 
B.  K.  E. 

B.K.E. 

B.  K.  B. 

B.  K.  E. 
B.  K.  E. 
B.  K.  E. 

B.  K.  E. 
B.  K.  E. 

B.K.E. 
B.  K.  E. 


(ILAGIAL  8TliI^. 
TAst  of  glavial  grooves  and  xtriw,  etc. — Coiititiued. 


523 


Locality. 


KBANKLIN  COUNTY— CODtinUOll. 

Greenliclil :  HouthofC.  andJ.S.  Newton's. 
Greunticlil :  road  to  lieoch  Hill 


Greenliehl ;  north  part  of  Petloral  street. 

Greenfield ;  west  of  factory  village 

Greeniirld ;  one-half  mile  northeast  of 

center. 
Grei'ntiold  ;  near  mouth  of  Mill  Brook. . . 

Gill ;  school  south  of  center 

Gill :  IJ  miles  north  of  Lily  Pond 

Gill ;  northwest  of  factory  village 

ErA'ing :   under  Dressers  Mountain   on 

south . 
Warwick ;  southeast  near  iron-ore  beds . . 

!Newyaleni;  200  rods  south  of  academy. 


Book. 


Sandstone  . 
....do  


....do 

....do 

Sandstone  . 


do 

Conglomerate. 

do 

Sandstone 

Gneiss 


Warwick:  near  meetinghouse 

Deerfield;  south  end  of  trap  nearest  to 

river. 
Deerfield:  mouth  of  gorge  of  Deerfield 

Elver. 

Deerlield ;  southeast  part 

Deerfield ;  northwest  part 

Deerfield;  gorge  of  Deerfield  River  in 

trap  range. 
Deerfield ;  at  west  entrance  of  above  gorge 

Montague ;  southwest  corner 

Montague ;  south  part 


Greentield :  north  edge  of  city,  S.J.  Lyons 


Montague ;  road  up  to  Turners  Falls  from 

lower  suspension  bridge. 
Sunderland ;  north  bend  of  north  wood 

road  onto  Mount  Toby. 

Sunderland ;  north  part,  near  cave 

Sunderland ;  nortbwest  of  cave , 


HAMPSHIRE  CODNTY. 

Plainfield;  south  of  S.  Barton's 

Plainfield;  northwest  corner 

Cummington;  northwest  comer,  oouth  of 
Deer  Hill. 

Ciunniiugton,  School  No  .10 


Cummington  end  of   blind  road   at  I. 

Farling's. 
Goshen;  southeast  part,  deserted  road 

west  of  Hubbard's  ledge. 


Mica-schist . 


Hornblende-schist 
Trap 


Sandstone  . 


Conglomerate. 
Mica-schist  ... 
Trap 


Sandstone 

Conglomerate. 
do 


Sandstone  . 


.do  . 


IConglomerate- 
do 


Sericite-schist . 
Amphibolite .  - . 
Sericite-schist . 


Conway  schist 


Sericite-schist 


Mica-schist . 


Direction. 


S.  30°  W  . 
S.  10°  B  . . 


S.  8°  E  . . . 
S.  25°  W . 
S.  8°  B  . . . 


S.  15°  W  . 
S.  20°  W . 
S.  200  w  . 
S.  25°  W . 
S.  40°  E  . . 

S.130  B.. 

•S.150  E.. 
.8.25°  E.. 
S.13°  E.. 
S.10°  W. 

S.  15°  W. 


S.  8°  E. 
S.8°  E. 
E 


S 

S.  12°  E.. 
,S.8°  E... 
S.  15°  E. . 
S.5°  W.. 
S.20°  W. 

S.50°  W. 

•S.5°  W.. 
Is.  10°  E.. 

S.  8°  W.. 

S.  10°  W. 


S.  35°  E . 
S.36°  E. 
S.60°  E. 

S.  10°  E. 
S.21°  E. 
S.45°  E. 
S.25°  E- 
S.45°  E- 
E 


Kemarks. 


Striae  and    grooves  3 
wide,  8  inches  deep. 
Very  distinct 


Very  distinct 


In  Millers  River  Valley  out 
of  Connecticut  Valley. 

Sometimes  several  feet  wide 
and  a  foot  deep. 

^On  high  ground 


East    slope    of     Deerfield 

Mountain. 
In  the  Connecticut  Valley. 


Finely  preserved 


Frequent 

Striae  runningup  hillside  45° 

Groove  2  feet  wide 

Groove  5  feet  wide,  rising 
slightly. 


In  bottom  of  deep  valley 
running  S.  60°  E. 


Moutonn6  over  a  broad  sur- 
face. 


Authority. 


B.K.E. 
B.K.E. 

E.  H. 
B.  K.  E. 
E.H. 

B.K.E. 
B.  K.  E. 
B.  K.  B. 
B.K.E. 
B.  K.  E. 


B.K.E. 

E.H. 
B.  K.  E. 

B.  K.  E. 

E.H. 

E.H. 

B.  K.  E. 

B.K.E. 
B.K.E. 
E.H. 

B.  K.  E. 


B.  K.  E. 


E.H. 
B.  K.  E. 


B.K.E. 
B.  K.  E. 
B.  K.  E. 


B.  K.  E. 

B.  K.  E. 
B.  K.  E. 


524  GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

List  of  glacial  grooves  and  strim,  etc. — Continued. 


Locality. 


Kock. 


Direction, 


Kemarka. 


Authority. 


HAMPSHIRE  COUNTY — continued. 
Groshen ;  farther  south 


Worthington ;  west  part 

"Worthington ;  west  part,  road  to  Middle- 
field. 
AVortbington  Center 

"Worthington ;  Stephens's  mills 

Worthington;  I  milenorthweat  of  center. 

Worthington;  first  crossroads  west  of 
center. 

Worthington  Center 

Amherst;  nortbeastspurof  Mount  War- 
ner. 

Amherst;  roadside  one-half  mile  north 
of  the  site  of  President  Clark's  house. 

Amherst;  northeast  of  center 

Pelham ;  west  slope  of  ridge  1  mile  north 
of  Hygeia. 

Middlefield  ;  near  meetinghouse 

Middlefield ;  one-half  mile  south 

Middlefield;  east  part,  near  soapstone 
quarries. 

^Northampton ;  high  upon  road  to  Eyrie 
House;  Mount  Nonotuck. 

Northampton;  southwest  corner  Kings- 
ley's  mill. 

Northampton ;  at  Eyrie  House  on  top  of 
the  mountain. 

Northampton ;  below  Smiths  Ferry  bird- 
track  locality. 

Northampton ;  1  mile  south  of  mountain, 
125  rods  northwest  of  where  road  to 
Westfield  branches. 

Hadley ;  second  peak  west  of  G-ap  road . . 


Hadley ;  same  peak,  west  fore  knob 

Hadley ;  same  peak  west  of  this  and  40 
feet  lower,  straight  pass  15  feet  wide, 
wholly  smoothed  and  scratched. 

Hadley ;  Mount  Holyoke  House 


Granby;  mouth  of  forge  pond 

G-ranby ;  north  part 

Granby;  Moody  Corners 

Southampton ;  south  of  center 

Southampton ;  east  of  village 

Easthampton;  Mount  Tom 

Easthampton ;  quarry,  west  shoulder  of 
Mount  Tom. 

Holyoke ;  south  of  Mount  Tom 

Belchertown;  42°  20',  72°  25' 


Micarschist . 


Sericite-schist . 
....do 


-do. 
.do. 
-do. 
.do. 


...-do  . 

Gneiss. 


Granite. 
Gneiss. . 


Sericite-schist . 

-...do  

do 


Arkose 

Granite 

Trap 

Sandstone . 
Trap 


-do. 


-do  . 
.do. 


.do  . 


Sandstone 

do 

do 

do 

Conglomerate - 

Trap 

Conglomerate. 


Sandstone  . 
Tonalite . . . 


S.  76°  W. 


S.22°  E. 
S.22°  E. 

8.40"  E. 
S.50O  E. 
S.650  E. 
S.  43°  E . 


S.  59°  W . 
S.150E.. 


N.  50°  W. 


S.  30°  E  . . 
S.  150  -w . 


S.220  E. 

s 

S 


S.  22°  W . 


S 

S.  25°  E . 
S.  60°  E . 


•S.50  W-- 
,S.2°  E... 
S.150  B.. 
S.8°  E... 
S.50  W.. 
S.  73°  W. 
S.120  W. 
S.8°  E... 
S6.0O  B.. 


S.  60°  E. 
N.80°E. 


Both  follow  direction  of  val- 
ley. 


300  feet  be]ow  top  of  hill. 


Stoss  side  observed.. 


Groove  2  feet  wide,  4  inches 

deep, 
li  feet  wide 


jSee  figs.  29,  30,  pp.  527, 530  -  - 


B.  K.  E. 

E.H. 
B.H. 

B.  K.  B. 
B.  K.  E. 
B.K.E. 
B.K.E. 

B.  K.  E. 
B.  K.  E. 

B.  K.  E. 

B.K.E. 
B.  K.  E. 

E.H. 
B.  K.  B. 
E.H. 

b.b:.e. 

E.H. 
B.  K.  E. 
B.K.E. 
B.  K.  E. 

B.  K.  E. 

B.  K.  B. 
B.K.E. 

B.K.E. 

B.K.E. 

E.H. 

B.K.E. 

E.H. 

B.K.E. 

E.H. 

B.  K.  E. 

B.K.E. 
G.  H.  Bar- 
ton. 


GLACIAL  STRI^. 

List  of  glacial  (jrooves  and  striw,  etc. — Continued. 


525 


Locality. 

Rock. 

Direction. 

Kemurka. 

Authority. 

HAMPDEN  CODNTT. 

Cheater:  top  of  Round  and  of  Gobble 
hills 

Blandford ;  one-balf  mile  north  of  meet- 
inghouse. 

Blandford;  North  stroet,  north  of  meet- 
inghouse. 

Emery 

Serioite-schist 

do 

do 

S.8°E?.... 
S.  8°E  ? 

Deeply   grooved    and 
smoothed. 

C.U.Shep- 

ard. 
E.H. 

B.K.E. 

B.  K.  E. 
B.K.E. 

B.K.E. 

E.H. 

B.K.E. 

B.K.E. 

E.H. 

B.K.E. 

B.K.E. 

B.K.E. 

B.K.E. 

E.H. 

E.H. 

E.H. 

E.H. 

E.H. 
E.H. 
E.H. 

E.H. 
E.H. 

E.H. 
B.  K.  E. 

S.  20°  E 

8.35-10°  E. 
S.  25-40°  E. 

Blandford;  North  street,  farther  north, 
crotch  in  road. 

do 

..  do 

S.40°  E.... 
8.73°  W... 

8.15°  W... 

Beautiful  deep  flutings,  8  to 

IS  inches  across. 
(Drumlins  here  run  south. 

B.K.E.) 

Westfieldj      sonthweat    from     Cowle's 
quarry,  south  of  mouth  of  gorge  of 
Little  River. 

Sandstone 

Conglomerate 

Trap      

8.30°  E 

Sandstone 

Hornblen  de-  schi  8 1 

8.73°  W... 

8.40°  E 

Tolland;  northeast  of  Noyes  Pond 

Tolland ;  south  of  mouth  of  Noyes  Pond. 

8  20°  E 

do 

8.10°  E 

do 

8.15°  E 

Granville;  middle,  1  mile  west  of  meet- 
inghouse. 

Granville;  north  part.Tnouth  of  deep 
gorge  in  Sodom  Mountain  opening  into 
Connecticut  Valley  in  Southwick,  near 
west  end,  near  house  of  Mrs.  Jones. 

do 

8.22°  E 

Mica-schist 

do 

8.60°  E.... 

8.62°  E.... 
8  20°  B 

630  feet  above  sea 

Thought  by  Dr.  Hitchcock 
to  have  been  a  local  gla- 
cier. 
do 

GranviUe;   2  miles  northwest  of   east 
Tillage,  Blandford  road. 
Do 

do 

.  ...do 

8.62°  E 

do   

do 

8  12°  E 

...  do 

N.80°E..  . 
8  80°  E     .. 

Thought  hy  Dr.  Hitchcock 
to  have  been  a  local  gla- 
cier. 
do 

do 

Russell;   southwest,  north  bank  Little 

River,  1,100  feet  above  sea. 
Russell;   southwest,  north  bank  Little 

River,  at  mouth  of  gorge. 

Agawam   and  Suffield,  Conn.;  one-half 
mile  east  of  east  foot  of  trap  ridge. 

do 

Sandstone 

N.80°E... 

Thought  by  Dr.  Hitchcock 
to  have  been  a  local  gla- 
cier. 

On  the  map,  PL  XI,  p.  510,  all  the  glacial  strise  tabulated  above  are 
entered,  together  with  some  from  the  map  in  the  Surface  Geology  of  Presi- 
dent Hitchcock.^  The  latter  are  transferred  as  accurately  as  possible,  and 
appear  without  indication  of  the  divergence  from  the  meridian,  as  that  is  not 


'  Surface  Geology,  Amherst,  1860,  pi.  8. 


526       GEOLOGY  OP  OLD  HAMPSHIRE  COUNTY,  MASS. 

given  upon  the  original  map.  So  far  as  the  southern  ]3art  of  the  State  Is 
concerned,  this  map  is  the  same  as  the  one  accompanying  the  report  of  1853, 
cited  above;  but  the  striae  with  abnormal  westerly  direction,  at  Kingsley's 
mills,  in  the  southwest  corner  of  Northampton  (southwest  of  Florence  on  the 
map  of  the  1853  report),  are  omitted  from  the  later  map.  Hence  we  may 
suppose  that  President  Hitchcock  came  to  doubt  the  observation  as  to  the 
stoss  side  being  on  the  east.  I  have  entered  the  strige  with  the  probable 
direction — namely,  east. 

The  map  (PI.  XI)  is  very  interesting  as  a  composite  of  (1)  the  general 
direction  of  the  ice  across  the  area  under  consideration;  (2)  the  simulta- 
neous deflection  of  the  ice  at  base  in  the  long  trough  of  the  Connecticut 
Valley ;  (3)  minor  deflections  around  prominent  obstructions  and  in  gorges, 
also  afi^ectiug  only  the  base  of  the  great  ice  sheet;  (4)  later  deflections  of 
frontal  lobes  of  the  ice  by  prominent  valleys ;  (5)  fanning  out  of  frontal  lobes. 

(1)  The  normal  direction  is  S.  35-40°  E.,  and  this  is  more  regularly 
manifest  beyond  the  confines  of  the  map  on  the  west. 

(2)  The  influence  of  the  Connecticut  Valley  in  deflecting  the  ice  south- 
ward seems  felt  for  a  considerable  distance  out  over  the  western  plateau. 

(3)  The  southward  deflection  in  the  valley  is  well  exhibited  and  is 
most  remarkable  on  the  top  of  the  Holyoke  range. 

(4)  The  local  influence  of  the  Greenfield  and  Deerfield  trap  ridges  of 
the  Cummington  Valley  and  the  Fall  River  and  Deerfield  River  notches  are 
well  marked,  producing  in  both  the  latter  cases  striae  at  right  angles  within 
and  without  the  gorges.  The  same  is  seen  at  both  ends  of  the  Mount  Tom 
range. 

(6)  The  curious  fanning  out  of  the  striae  north  of  Westfield,  S.  73°  W. 
and  S.  60°  E.,  seems  to  indicate  a  valley  lobe  of  the  ice  extending  south 
between  Mount  Tom  and  Mount  Pomeroy  to  the  west,  and  expanding  to 
the  south  where  the  valley  widens  toward  Westfield.  A  similar  fanning 
out  is  indicated  in  the  main  Connecticut  Valley  by  the  direction  S.  50°  W. 
in  Agawam  and  Suffield. 

The  southwesterly  direction  above  Shelburne  Falls  and  the  easterly 
direction  down  all  the  valleys  opening  from  the  western  highlands  into  the 
main  valley  were  due  to  later  lobes  in  the  retreating  ice  front. 

The  most  remarkable  groovip.g  and  fluting  is  found  along  the  whole 
crest  of  the  Holyoke  range  on  the  hard  trap.     Near  the  Prospect  House, 


GLACIAL  STRIJB.  527 

on  ALouut  llolyoko,  are  some  of  the  most  remarkable  grooves  I  have 
seen.  One  northeast  of  the  house,  between  tlie  two  iron  boundary  posts, 
is  at  tlie  north  end  2  feet  wide  and  shallow,  at  the  south  end  1  foot  wide 
and  8  inches  deep.  Several  other  grooves  almost  equally  marked  occur 
near  this.     Their  direction  is  S.  2°  E. 

A  curious  groove  (fig.  29)  comes  out  from  mider  the  house  on  the 
southwest  side  and  runs  in  a  southwesterly  dii-ection.  This  is  exposed  best 
in  the  bottom  of  an  unused  reservoir,  and  can  be  traced  for  a  length  of 
12  feet.  It  is  about  2  J  feet  wide  by  10  inches  deep,  the  greatest  depth 
being  at  the  east  side,  which  is  overhanging,  being  fluted  regularly  like  a 
letter  S.  This  seems  to  me  to  have  been  caused  possibly  by  water  run- 
ning beneath  the  ice  and  to  be  a  true  "  lapiaz,"  as  they  occur  beneath  the 
ice   of  the  Alpine   glaciers.      It 

must,   then,  have  been  polished  ^^  ,, .  ....^. ^ 

by  the  ice  at  a  later  time.  ,/ 

High  up  on  the  road  to  the 
Eyrie  House,  on  Mount  Nono- 
tuck,  deep  strise  run  S.  22°  W., 
deflected  westward  in  the  direc- 
tion of  the  Easthampton  valley, 

while  on  the  summit  above  broad,  ^"^-  29.— eiacial  groove  on  compact  aiabase,  Prospect  House, 

-  Mount  Holyoke. 

deep   grooves    abound,    running 

north  and  south.  South  of  the  Holyoke  range,  at  Smiths  Ferry,  the 
strise  run  S.  25°  W.,  on  trap.  At  Batterson's  sandstone  quarry,  south  of 
Moimt  Holyoke,  at  E.  H.  Lyman's  house,  the  fine-grained  sandstone  is 
grooved  and  fluted  and  sca-atched  most  beautifully  over  a  broad  surface 
(see  PI.  X,  p.  488).  The  ice  met  the  vertical  and  overhanging  face  of  the 
sandstone  and  fitted  itself,  so  exactly  to  it  that  scratches  and  polishing  occur 
on  surfaces  placed  at  all  angles  to  the  horizon,  even  upon  the  under  side  of 
projecting  ridges.  In  the  vertical  westward-facing  wall  the  basset  edges  of 
the  horizontal  sandstone  beds  are  polished  like  glass,  and  one  thin,  softer, 
shaly  bed  is  cut  in  deeply  to  form  a  long  groove  10 J  inches  deep  and  only 
3  inches  wide  at  the  mouth,  but  polished  to  the  bottom,  where  it  is  but  a 
half  inch  wide.  The  direction  of  the  scratches  is  here  very  irregular,  going 
to  all  points  both  in  altitude  and  azimuth.  The  prevalent  direction,  how- 
ever, over  the  broader,  flatter  surfaces  is  south. 


528  GEOLOGY  OF  OLD  HAMPSHIEB  COUNTY,  MASS. 

I  hardly  need  call  attention  to  the  magnitude  and  the  peculiar  char- 
acter of  the  force  which  has  done  this  work,  grinding  down  all  the  pebbles 
of  a  conglomerate,  hard  and  soft  alike,  to  a  common  level,  as  can  be  well 
seen  on  the  road  which  goes  over  the  north  shoulder  of  Mount  Toby  just 
after  leaving  the  Sunderland  road,  and  cutting  grooves  in  the  trap,  a  rock 
so  tough  that  one  rarely  attempts  to  drill  a  hole  in  it,  preferring,  when  it 
is  necessary  to  remove  it,  to  do  the  work  by  building  fires  upon  it  and 
drenching  the  rock  with  water,  by  which  means  it  is  crumbled  and  slowly 
removed.  Two  men  and  a  holder  drill  only  8  feet  a  day  in  trap.  These 
grooves  are  of  all  dimensions,  ranging  from  fine  lines,  visible  only  in 
oblique  light  with  a  lens,  to  broad  troughs. 

Even  more  striking  is  the  polishing  of  the  surface  of  the  great  emery 
vein  in  Chester,  which  for  a  distance  of  several  rods  near  the  summit  of  each 
mountain  has  been  deeply  grooved  and  polished  by  glacial  action.  That 
the  friction  producing  this  effect  must  have  been  enormous  is  apparent  from 
the  size  and  depth  of  the  channels,  and  that  it  could  not  have  been  the 
result  of  running  water  is  demonstrated  by  recurring  to  the  example  of 
river  action  in  the  Westfield  River  upon  another  portion  of  the  same  bed, 
where  we  have  an  eroded,  pitted  surface  from  which  the  coarse  crystalline 
particles  of  the  hard  emery  are  left  projecting.^ 

Another  point  deserving,  perhaps,  further  consideration  here  is  the 
great  degree  of  irregularity  in  the  direction  of  the  striae,  since  these  give 
accurately  the  direction  of  the  motion  of  the  ice  at  the  time  they  were 
made.  For  many  of  these  differences  of  direction  we  may  assume,  as  above, 
(p.  526)  that  they  were  variations  in  the  direction  of  the  motion  of  the  ice 
at  different  times.  For  most  we  must  assume  that  the  great  ice  sheet  was 
affected  by  the  greater  irregularities  of  the  bottom  over  which  it  flowed, 
just  as — to  use  the  illustration  given  by  Prof  J.  D.  Dana  (to  whom  we  owe 
this  explanation  and  its  application  to  the  anomalous  north-south  direction 
of  the  ice  in  the  Connecticut  Valley) — a  mass  of  pitch  flowing  down  an 
inclined  board  upon  which  strips  had  been  nailed  at  various  angles  to 
the  line  of  inclination  would  in  its  under  parts  be  deflected  behind  the 
strips  and  flow  in  the  direction  of  the  grooves  thus  produced.  Ice,  in  short, 
though  moving  with  extreme  slowness,  comports  itself  like  a  fluid  and 
obeys   the   laws   of  hydraulics.     Thus  the  line  of  motion   for  the   great 

'  C.  U.  Shepard,  Report  on  Chester  Emery  Mine,  p.  5. 


GLACIAL  NOTCHES.  529 

mass  of  tlie  ice  over  Hampshire  County  was  S.  35°  E.,  while  the 
lowest  portions  in  the  broad  depression  of"  the  Connecticut  Valley  moved 
with  that  valley  from  north  to  south,  and  even  west  of  south  along  the 
Mount  Tom  range.  While  this  explanation  is  surrounded  with  difficulties, 
it  does  explam  in  a  very  satisfactory  way  many  peculiarities  of  the  character 
and  distribution  of  the  till  in  the  valley,  as  will  be  made  clear  in  the  next 
sections. 

GLACIAL  NOTCHES. 

Another  remarkable  series  of  phenomena,  which  we  may  possibly  refer, 
in  whole  or  part,  to  the  direct  action  of  the  ice  upon  the  rocky  floor  over 
which  it  moved,  is  to  be  found  in  the  succession  of  notches  of  varying  depth 
which  cut  the  Holyoke  chain  transversely  in  its  east-west  portion  and 
give  it  the  appearance  of  a  sierra  in  miniature.  One  of  these  cuts  the 
ridge  to  its  base,  forming  the  notch  through  which  the  river  flows.  Two 
cut  down  deep  into  the  heart  of  the  mountain,  forming  low  cols, 
thi'ough  the  western  of  which  the  road  runs.^  Others  are  shallower,  and 
one  may  find  a  quite  complete  series  connecting  them  with  the  ordi- 
nary glacial  grooves  and  scratches.  The  larger  notches  are  themselves 
scratched  and  polished,  and  the  direction  of  the  scratches  coincides  with 
the  axis  of  the  notches  themselves. 

Another  circumstance  harmonizes  with  the  idea  that  they  were  formed 
by  a  force  like  that  of  moving  ice,  the  direction  of  whose  action  was  in  great 
degree  independent  of  the  relative  hardness  and  direction  of  the  ridge. 
The  Holyoke  range  lies  like  a  blowpipe  with  the  mouthpiece  pointing  south 
and  the  point  directed  east.  So  long  as  the  chain  runs  east  and  west  the 
grooves  cross  it  at  right  angles,  running,  as  did  the  ice  in  the  valley,  north 
and  south,  while  as  the  ridge  swings  round  from  west  to  south  the  succeeding 
notches  run  parallel  to  the  first  and  cut  the  chain  more  and  more  obliquely 
TUitil  the  last  coincides  with  the  southward  prolongation  of  the  mountain 
and  splits  it;  and  one  looking  at  the  trap  from  the  west — in  Southampton 
or  Easthampton,  for  instance — sees  the  almost  vertical  cliff  of  trap  bounded 
above  by  a  line  which  deviates  little  from  horizontality,  instead  of  the 
serrate  sky  line  of  the  Holyoke  range  proper  as  seen  from  Amherst. 

'This  used  to  be  called  the  East  Crack,  the  deep  notch  just  east  of  the  Holyoke  Mountain  House 
being  known  as  the  West  Crack,  and  there  was  once  a  road  through  this  also ;  and  the  deepest  depres- 
sion between  these  was  the  Low  Place. 
MON  xxix 34 


530 


GEOLOGY  OP  OLD  HAMPSHIRE  COUNTY,  MASS. 


This  rule  is  not  without  exceptions,  since  the  pass  which  separates 
Mount  Tom  from  the  next  peak  trends  a  Httle  north  of  east,  and  the  next 
passage  north  trends  east  and  west.  President  Hitchcock  argued  as  follows 
concerning  the  matter :  ^ 

If  these  notches  had  been  determined  by  anything  in  direct  relation  with  the 
trap  of  the  mountain,  the  most  probable  cause  would  have  been  a  Assuring  of  the 
bed  of  trap  during  its  upheaval,  and  as  this  Assuring  would  have  occurred  most 
naturally  at  right  angles  to  the  axis  of  the  chain,  the  Assures  would  have  con- 
verged on  a  point  south  of  the  mountain,  somewhere  about  the  northwest  corner  of 
Ludlow. 

So  he  concluded  that  if  tlie  first  notches  he  noticed  (those  cutting  at 
right  angles)  were  caused  by  Assuring,  those  farther  west  would  be  also 

at  right  angles  to  the  chain  there 
and  parallel  with  the  dip  there; 
and  when  he  found  this  was  not 
the  case,  he  explained  them  as  a 
strange  result  of  the  great  north- 
em  diluvial  current  which  did 
duty  then  in  place  of  the  ice  cur- 
rent of  more  modern  theories.-' 

The  larger  notches  seem  to 
have  been  caused  hj  the  system 
of  faults  which  cut  the  range, 
and  to  have  been  enlai'ged  by 
pre-Glacial  streams  (see  PL  XI, 
p.  510)  in  case  of  two  or  three 
of  the  deeper  ones.  Where,  as  is 
often  the  case,  these  faults  fail  to  run  north  and  south,  the  notches  may 
have  been  remodeled  by  the  ice  and  given  a  new  direction,  and  the  great 
number  of  smaller  notches,  all  parallel  with  the  direction  of  the  ice,  do 
not  seem  explicable  as  a  result  of  water  action,  but  rather  as  the  work  of 
the  ice  acting  on  the  irregular  rim  of  the  trap  sheet,  which  emphasized 
irregularities  where  this  rim  ran  athwart  the  course  of  the  ice,  as  in  the 
Holyoke  range,  and  smoothed  them  down  whfere  the  rim  ran  with  the 
ice,  as  in  Mount  Tom. 


Fig  30 East  slope  of  a  large  glaciated  groove  behind  the  bowl 

ing  alley  on  Mount  Holyoke. 


'  Geology  of  Massachusetts,  1841,  p.  389. 


GLACIAL  NOTCUES.  531 

'I'hus  it',  atU'V  cxaniiuiiif''  the  marked  grooves  under  and  noi'tli  of  the 
Prospect  Mouse  on  Mount  Holyoke,  one  goes  a  few  rods  east  to  the  groove, 
about  12  feet  deep  and  of  equal  width,  just  beliind  the  bowling  alley  (see  fig. 
30),  one  will  find  it  hard  to  draw  the  line  between  them.  And  if,  after  exam- 
ining the  grooves  and  striae  on  the  second  peak  west  of  the  notch,  one  goes 
down  west  into  the  deep  groove  about  40  feet  across,  the  similarity  in  direc- 
tion and  shape  will  lie  foun.d  very  striking;  and  such  cases  are  quite  common. 

PSEUDO-GLACIAIj  STEI.^   on  DEVONIAN  ARGILLITES. 

While  examining  the  garnetiferous  mica-schists  at  Purple's  quarry,  in 
the  east  part  of  Bernardston,  I  was  attracted  by  a  peculiar  striation  which 
occurred  upoii  a  broad,  flat  cleavage  surface  of  the  nearly  horizontal  slates 
and  continued  beneath  the  superincumbent  beds.  The  surface  in  question 
was  just  at  the  north  edge  of  the  water  which  fills  the  abandoned  quarry, 
and  was  certainly  in  place  and  undisturbed,  and  I  raised  the  slates  which 
rested  upon  it  and  followed  the  striation  beneath,  for  a  foot  or  more  inward 
without  seeing  anything  which  suggested  to  me  that  these  upper  layers 
were  not  also  in  place  and  undisturbed. 

Clear  impressed  lines,  from  those  so  fine  as  to  be  seen  only  with  a 
lens  up  to  those  a  millimeter  in  diameter,  covered  the  broad,  flat  surface — 
in  average  about  an  inch  apart — the  larger  showing  a  delicate  longitudinal 
striation.  These  grooves  vary  in  length  between  quite  wide  limits — 1  to  6 
inches.  The  larger  number  are  straight,  or  nearly  so ;  very  many  form 
easy  open  curves,  single  or  double.  Over  most  of  the  surface  two  distinct 
systems,  making  an  angle  of  40°  with  each  other,  were  apparent,  the  one 
having  the  longer  and  finer  lines  and  most  of  the  long  curving  lines,  the 
other  being  somewhat  broader,  shorter,  and  more  rigidly  parallel  and 
straight.  Their  length  varied  very  little  from  an  inch,  and  they  were  often 
slightly  gouged  out  at  the  end.  On  putting  several  parts  together,  so  as  to 
get  a  broad  surface,  the  finer  lines  of  the  first  system  are  seen  to  bend  and 
continue  in  the  second  system. 

The  whole  impression  was  quite  like  that  of  the  rain-marks  on  a  car 
window  before  and  after  starting.     Faint  traces  of  a  third  system  at  right 
angles  to  the  first  are  also  present.     The  direction  in  the  rock  was  not  taken, 
as  the  marks  were  supposed  to  be  of  mineral  or  organic  origin;  many  of 
them  strikingly  resemble  in  size,  curvature,  etc.,  impressions  of  Graptolithus 


532  GEOLOGY  OP  OLD  HAMPSHIEE  COUNTY,  MASS. 

minutus.     A  suggestion  of  long  needles  of  hornblende  or  chiastolite  also 

occurred. 

On  further  examination  the  minute  garnets  on  the  surface  were  found  to 
be  polished  down  and  scratched  like  the  rest.  At  one  portion  of  the  surface 
unmistakable  glacial  striae  were  found  adjoining  the  problematical  grooves. 
That  the  marks  were  formed  by  movement  of  an  upper  layer  of  the  slate  on 
the  underlying  ledge  seemed  clear,  and  that  the  garnets  fixed  in  the  bottom 
of  the  upper  moving  stratum  furnished  the  grooving  tools.  The  change 
in  the  direction  was  caused  by  a  change  in  the  direction  of  the  moving 
mass,  some  portion  of  the  bottom  becoming  fixed  and  forming  a  pivot 
around  which  the  rest  revolved.  That  the  mass  was  moved  only  a  slight 
distance  from  its  original  position  was  also  clear.  Whether  this  motion 
was  caused  by  glacial  ice,  by  the  expansion  and  contraction  of  the  rock, 
or  by  earthquake  action,  I  can  not  decide. 

POT-HOLES. 

President  Hitchcock  notes  ^  the  absence  of  pot-holes  among  the  results 
of  the  diluvial  currents  which  were  supposed  to  have  originated  the  till  and 
the  glacial  striae,  and  concludes  therefrom  that  these  phenomena  were  not 
the  work  of  rivers  but  of  widespread  currents  without  falls  of  much  magni- 
tude. He  describes  later  a  great  series  of  pot-holes  west  of  Shelburne  Falls, 
on  the  road  to  Charlemont,  in  an  old  bed  of  the  Deerfield  River,  85  feet 
above  the  present  stream,  which  may  have  belonged  to  a  pre-Grlacial  bed  of 
the  river  or  may  be  of  Glacial  age. 

Pot-holes  occur,  of  course,  along  the  channel  of  the  Connecticut  and 
its  tributaries,  in  the  former  especially  below  its  falls  in  the  canyon  formed 
by  their  recession,  in  the  latter  on  the  bottoms  of  the  deep  gorges  they 
have  cut  through  the  crystalline  rocks. 

Striking  illustrations  are  to  be  seen  in  the  Westfield  River,  at  the 
Crescent  Paper  Mills,  in  the  extreme  north  of  Russell.  Just  below  Russell 
station  also  a  great  dike  of  granite  formerly  obstructed  the  stream,  but  has 
been  cut  through,  and  here  are  many  pot-holes.  One  interesting  one  was 
half  removed  as  the  stream  cut  down  its  bed,  and  the  remaining  half  is 
still  to  be  seen  in  the  wall,  about  10  feet  above  the  water.  It  is  regularly 
urn-shaped,  with  bent  constricted  neck,  and  is  about  6  J  feet  deep. 

'  Final  Report,  1841,  p.  392. 


THE  TILL.  533 

liy  far  the  finest  development  of  river  pot-holes  is  in  the  almost  inac- 
cessible canyon  of  the  south  branch  of  Westfield  River,  one  of  which  is 
25  feet  deep  and  20  by  10  feet  at  the  mouth.  They  exist  abundantly 
along  the  coiu-se  of  Deerfield  River,  in  many  cases  high  above  the  present 
level  of  the  river,  as  noted  by  President  Plitchcock.  I  counted  more  than 
50  on  a  single  reef  of  sandstone  which  projects  into  Deei-field  River  at  the 
most  northerly  point  reached  by  the  stream  before  it  turns  towai'd  its 
notch  in  the  trap  range.  One  is  found  by  the  road  to  the  south  side  of 
Catamount  Hill,  in  Colerain,  2  feet  deep  and  1^  feet  wide. 

The  only  pot-hole,  however,  which  I  can  without  hesitation  assign  to  the 
Glacial  period  I  found  by  the  roadside  under  the  steep  southern  face  of 
Sugar  Loaf,  in  South  Deerfield.  It  is  in  red  sandstone  at  a  point  130  feet 
above  sea,  and  is  2  feet  deep  and  2  feet  wide.  From  its  position  it  must 
have  been  formed  during  some  phase  of  the  Glacial  period,  as  it  lies  apart 
from  any  probable  stream  bed,  and  the  surface  of  the  sandstone  around  it 
is  striated.  I  have  surmised  that  these  usual  accompaniments  of  glacial 
action,  which  we  should  especially  expect  to  find  in  so  irregular  a  region, 
may  have  been  many  times  formed  and  again  eroded  and  destroyed  by  the 
ice,  and  that  tliis  may  be  the  origin  of  many  of  the  spherical,  ovoid,  and 
flat-ellipsoidal  pebbles  of  quartz  which  occur  here  in  considerable  numbers 
in  the  true  till  and  which  agree  quite  exactly  in  form  with  the  polishing 
stones  of  a  pot-hole.  However,  they  may  belong  to  a  coarse-pebble  beach 
of  inter-Glacial  age,  synchronous  with  the  pink  sands  described  below. 

THE  TILL. 

INTRODUCTION. 

Pure  ice  moving  over  the  country  would  by  its  thrust  tear  off  project- 
ing portions  of  the  subjacent  ledges,  but  could  not  alone  polish  and  scratch 
the  rocks  as  we  find  them  now.  The  agents  of  this  work  were  the  stones 
themselves,  which,  torn  from  their  places  and  frozen  in  the  ice,  trans- 
formed it  into  an  immense  rasp  and  increased  its  eroding  power  many  fold. 
By  the  melting  and  freezing  of  the  lowei-  surface  and  by  the  slow  intestinal 
motion,  as  well  as  by  the  sudden  fissuring  of  the  mass,  its  lower  portion 
would  become  filled  with  a  large  and  varying  quantity  of  loose,  rocky 
material. 

Also,  where,  by  secular  decomposition,  as  indicated  on  page  374,  the 
rocks  had  become  softened  to  great  depth,  the  whole,  soaked  with  water,, 


534  GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

might  be  frozen  into  a  solid  mass,  and  the  snows  gathering  on  this,  it  might 
with  httle  change  become  the  base  of  the  glacier  and  be  moved  on  bodily 
Mnch  of  the  same  material  was  pushed  along  beneath  the  ice,  its  parts 
crushed  and  ground  against  each  other,  whereby  all  the  softer  rocks  were 
soon  reduced  to  an  impalpable  mud,  the  larger  and  the  harder  ones 
enduring  longer,  but  all  at  last  yielding  to  the  same  fate,  unless,  worked 
up  into  the  ice  itself  or  gathered  in  thick  accumulations  beneath  it,  they 
were  shielded  from  the  more  violent  action  of  its  mass.  The  ice  was, 
however,  constantly  providing  itself  with  new  material,  and  soon  wore  the 
fragments  into  the  peculiar  shapes  so  characteristic  of  glacial  accumula- 
tions, three-  and  four-sided  forms,  with  irregular  ends  more  or  less  elongate 
as  the  rock  was  more  or  less  schistose,  the  sides  flat  or  broadly  convex, 
joined  by  rounded  edges  and  scratched  in  various  directions. 

These  peculiar  forms,  called  by  the  G-ermans  "  dreikantner,"  are  as 
characteristic  of  the  till  as  graptolites  of  the  Silurian.  Thus  the  ice 
elaborated  in  immense  quantity  a  peculiar  subglacial  material  of  varying 
but  always  characteristic  composition,  and  spread  it  with  unequal  and 
sometimes  with  very  considerable  thickness  upon  the  rocky  surface.  For 
the  ice  did  not  everywhere  and  ahvays  rest  with  its  rasping  surface  upon 
the  rock  and  grind  into  it  without  interaiission.  Over  a  given  surface  it 
might  wear  for  a  long  time  continuously,  but  by  this  means  a  new  surface 
would  be  gradually  produced,  partly  by  the  unequal  force  of  the  ice,  partly 
from  the  varying  hardness  of  the  rock,  and  this  would  react  upon  the 
ice,  producing  slight  variations  in  its  subordinate  currents,  transferring  its 
intenser  action  to  another  area  and  alloAving  it  to  deposit  material  over 
the  first  area.  At  a  later  time  the  maximum  of  eroding  power  might  be 
transferred  back  to  its  former  position  and  the  accumulation  so  laboriously 
brought  together  would  be  again  swept  away.  In  this  way  one  may 
explain  some  of  the  cases  where  the  rock  surface  shows  striae  in  two 
directions,  for  the  local  movement  of  the  ice  might  be  somewhat  different 
at  widely  separated  times. 

Very  commonly  the  ice  heaped  up  its  accumulations  in  the  rear  of  some 
obstruction  in  a  long  ridge  projecting  from  the  obstructing  rock  in  the  direc- 
tion in  which  the  ice  was  moving,  as  the  water  arranges  sands.  At  other 
places,  especially  in  broad  open  portions  of  a  valley,  the  ice  molded  its  fine 
clayey  moraine  material  into  massive  hills,  called  drumlins,  rounded  and 


THE  TILL.  535 

eloii<j'iitr  ill  tilt'  (lii-('cti(tn  of  its  iiiotidii,  like  ;iii  iuvert(!(l  cHiioe.  These 
one  may  compiirc  \\itli  the  l)iir.s  of  a  river,  and  thus  complete  the  almost 
perfect  i)arallel  between  the  two. 

Tlie  study  of  these  deposits  is  very  difficult  (the  hardest  ]iroblems  in 
the  g-eolog'ical  book  are  at  the  beginning  and  the  end)  because  they  often 
blend  intricately  with  succeeding  deposits  and  are  largely  concealed  by 
them,  and  because  they  can  be  successfully  studied  only  in  fresh  exca- 
vations. In  a  few  days  the  exposure  caves  and  sinks  into  a  slope  which 
often  loses  all  its  characteristic  peculiarities  of  the  deposit.  For  this  realson 
the  following  desci'iptions  have  reference  almost  always  to  fresh  exposures, 
and  especially  where  the  color  or  consistency  of  the  bed  is  discussed  the 
reference  is  to  a  surface  newly  opened  up  and  still  moist. 

The  deposits  of  the  basin  which  we  may  refer  to  the  "moraine  pro- 
fonde"  of  the  inland  ice  and  which  we  may  believe  to  have  rested  beneath 
the  ice  wholly  completed  in  the  form  in  which  we  now  find  them,  at  a  time 
when  the  ice  was  so  far  thinned  by  melting  that  it  had  ceased  to  advance 
and  only  awaited  its  final  dissolution,  may  be  divided  into  three  groups  of 
only  local  value,  whose  diiTerences  in  structure  depend  in  large  degree  upon 
their  position  in  the  valley  or  their  altitude  above  it.  These  are  the  upland 
di'ift,  the  fine  valley  drift,  and  the  coarse  valley  drift. 

THE    UPLAND    DRIFT. 

Using  the  old  word  drift  (although  it  has  somewhat  gone  out  of 
fashion  in  late  years,  and  although  it  contains  always  some  reminiscences  of 
earlier  theories  now  wholly  abandoned)  for  the  explanation  of  the  phenomena 
with  which  we  are  now  occupied,  we  will  take  the  section  exposed  by  the 
ditch  for  the  wa,ter  main  from  the  west  village  of  Pelham  eastward  to  where 
the  Shutesbury  road  branches  off.  In  this  exposure  a  face  1,300  feet  long 
and  5  feet  deep,  320  feet  above  sea,  in  many  places  showing  the  underlying 
rock,  was  open  for  study. 

This  mass  is  wholly  free  from  clay  qr  fine  sand,  and  consists  in  the 
main  of  fragments  of  rock  of  various  sizes  up  to  4  feet  on  a  side,  with  a 
considerable  preponderance  of  those  about  1  foot  in  diameter.  These 
bowlders  are  almost  wholly  local — that  is,  they  consist  of  the  ordinary 
Pelham  gneiss  upon  which  they  rest — with  very  rarely  a  fragment  of  the 
compact  trap  which  occurs  a  few  rods  north. 


536  GEOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 

A  careful  search  of  the  material  thrown  out  of  the  ditch  revealed  a 
single  well-worn  bowlder  of  the  Vermont  quartzite,  and  one  of  an  epidotic 
quartz-diorite  (tonalite),  which  may  have  com^  across  the  valley  from  Hat- 
field, but  is  more  probably  derived  from  the  outcrop  of  the  same  rock  half 
a  mile  north.  All  the  fragments,  with  the  exception  of  the  far-traveled 
bowlder  of  quartzite,  are  quite  angular  and  unworn,  and  the  gneiss  ledges 
upon  which  the  deposit  rests  is  jagged  and  serrate,  the  rock  dipping  25° 
west  and  being  jointed  at  right  angles  to  the  bedding.  It  is  manifest  that 
the  ice  was  here  not  polishing  but  rudely  tearing  mp  the  ledge  and  moving 
onward  the  fragments,  and  in  several  cases  great  masses  could  be  seen,  3  or 
4  feet  in  diameter,  which  had  been  moved  but  small  distances  from  the  ledge 
and  could  be  fitted  back  into  the  places  from  which  they  had  come.  A 
coarse  sand  fills  the  interstices  of  the  larger  fragments  and  here  and  there 
constitutes  the  greater  portion  of  the  mass.  The  whole  is  reddish  for  2  feet 
down,  then  bluish  or  whitish  to  the  bottom.  In  one  place  it  is  blackened 
with  carbonaceous  material  for  a  rod  to  a  depth  of  4  feet,  and  below  this 
blackened  area  and  for  several  feet  on  either  side  it  is  blue.  Here  a  swale 
crossed  the  line  of  the  ditch  and  the  decomposing  carbonaceous  material 
deprived  the  infiltrating  waters  of  the  oxygen,  which  has  over  the  rest  of  the 
section  peroxidized  the  iron  to  a  depth  of  about  2  feet  in  most  places, 
though  sometimes  the  reddening  extends  below  the  bottom  of  the  ditch  5 
feet.  It  is  clear  that  this  locality,  placed  high  upon  the  eastern  rim  of  the 
basin  and  facing  westward  into  the  valley,  received  the  full  impact  of  the 
ice,  while  the  waters  moving  beneath  the  latter,  produced  in  part,  perhaps, 
by  the  very  friction  of  the  work  whose  effects  we  see  here  so  plainly, 
washed  out  all  the  finer  material  into  the  valley  below. 

The  above  section  may  be  taken  as  a  typical  illustration  of  a  deposit 
spread  in  a  broad,  irregular,  interrupted  sheet  on  the  rock  over  much  of 
the  elevated  country  bordering  the  basin.  It  is  irregular  in  thickness,  dis- 
tribution, and  internal  structure.  Upon  bi'oad  surfaces  of  naked  rock  the 
ice  rested  and  deposited  nothing,  or  in  later  times  atmospheric  agencies  have 
removed  what  was  laid  down.  In  sheltered  places  it  was  heaped  up  in 
great  thickness ;  in  other  places  it  is  represented  only  by  scattered  bowlders 
resting  upon  the  bare  ledges.  And  when  examined  as  to  its  internal 
structure  it  is  found  to  vary  greatly  in  the  size  of  the  stones  constituting 
the  mass  and  in  the  proportion  of  far-traveled  bowlders  entering  into  its 
composition.      All  around  the  valley  the  line  of  the  highest  lake  terrace  is 


THE  TILL.  537 

(juite  distinctly  traceable  as  the  lower  limit  of  continuous  forest  growth- 
The  Florence  plain  on  the  west,  the  Long  plain  in  Leverett  on  tlie  east, 
and  the  Bay  road  on  the  south  mark  this  level  in  Hampshire  County,  tlie 
Sj)i'ingtiel(l  and  Hampden  plains  in  Hampden  County,  and  the  Montague 
and  Northfield  plains  in  Franklin  County.  Above  tliis  line  the  surface  is 
almost  everywhere  formed  by  this  deposit,  the  only  exceptions  being  where 
the  bare  ledges  appear  or  where  it  is  covered  by  the  heavy  sand  of  the 
Glacial  lake  beds  described  further  on.  It  is  interesting-  to  see  how  o-en- 
erally  around  the  whole  border  of  the  basin  the  upoer  limit  of  the  culti- 
vated fields  coincides  with  this  purely  geological  line  which  I  have  drawn 
as  the  upper  limit  of  the  later  lake  deposits  of  the  valley.  Above  that, 
especially  if  we  make  exception  of  the  broad  sand  reaches  in  Pelham, 
Shutesbury,  and  farther  south,  most  of  the  region  is  a  rocky  waste  suitable 
only  for  growing  wood  or  pasturage,  although  where  the  deposit  is  fine 
enough  to  furnish  any  earth  at  all  it  is  a  soil  of  very  considerable  fertility 
and  one  not  easily  exhausted.     It  is  an  especially  good  grass  land. 

THE    FINE   VALLEY    DRIFT    OF    THE    EAST    SIDE    OF    THE    VALLEY. 

Very  unlike  the  coarse  incoherent  drift  of  the  uplands  is  the  stratum 
of  the  same  age  spread  over  the  bottom  of  the  valley.  It  has  been  called 
by  various  names,  as  "drift,"  "unmodified  drift,"  "till,"  "lower  till," 
"bowlder  clay,"  "hardpan;"  and  the  last,  the  common  name  of  the  deposit 
over  New  England,  is  most  characteristic.  It  is  an  excessively  compact, 
wholly  unstratified  clay  of  a  somber  gray  color,  always  more  or  less 
sandy,  and  stuck  full  of  glaciated  bowlders,  those  from  5  to  8  inches  in 
length  predominating  greatly,  while  of  those  above  a  foot  in  diameter 
very  few  occur  in  the  many  sections  of  the  true  lower  till  which  I  have 
examined  in  this  basin. 

When  examined  under  the  microscope  it  is  found  to  contain  only  a 
very  small  quantity  of  true  clay  or  kaolin,  the  iisual  product  of  the  decom- 
position of  feldspar.  It  is  more  properly  described  as  an  extremely  fine 
rock  flour,  the  sharply  angular  grains  of  which  are  mostly  quartz  and 
feldspar.  And  this  is  easily  explicable  when  we  consider  its  origin — that  it 
is  produced  not  by  the  slow  decomposition  of  the  rocks  and  the  sorting 
out  of  the  finer  clayey  portion  by  running  water,  but  that  it  represents  the 
finer  portion  of  material  produced  by  the  grinding  up  of  rocks  largely 


538  GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

undecomposed  and  also  largely  siliceous.  Small  pockets  of  water-washed 
saud  occur  somewhat  rarely,  generally  as  broad  sheets  less  than  a  foot  in 
thickness  and  dipping  often  at  a  high  angle.  .They  merge,  often  with 
various  contortions  of  their  layers,  into  the  normal  till,  and  are  plainly 
remnants  of  deposits  made  by  subglacial  water  seams,  which  were  not 
wholly  molded  into  the  common  mass  by  the  later  work  of  the  glacier. 

The  exceeding  compactness  of  the  mass  is  a  factor  of  prime  impor- 
tance in  any  consideration  of  the  origin  of  the  deposit,  since  it  caii  be 
explained  only  by  assuming  it  to  have  been  caused  by  the  great  weight 
of  the  ice  which  rested  upon  it.     For  a  long  time  I  thought  it  possible  to 
explain  this  as  due  to  the  slow  compacting  of  a  mass  of  loose  material  of 
various  sizes  aided  by  the  percolation  of  water,  but  when  once  dug  up  and 
thrown  in  heaps  it  becomes  compact  again  only  when  drj^,  as  does  also 
the  Champlain  clay,  which  hes  above  it.      When  water-soaked,  however, 
it  sinks  i-eadily  into  fine  mud.     When  both  are  in  their  original  position 
aaid  have  not  been  disturbed  and  are  still  permeated  with  water,  one  can 
easily  pusli  a  cane  several  feet  into  the  clay,  but  could  scarcely  penetrate 
the  till  more  easily  than  the  sandstone.     Where  this  till  is  well  developed 
a  workman  will  often  not  remove  more  than  a  yard  of  it  in  a  day.     In 
dio-jring  the  cellar  of  the  Amherst  House  the  attempt  was  made  to  split  it 
off  in  blocks  by  means  of  large  wedges  and  sledges,  but  the  best  steel 
was  rapidly  blunted,  and  these  were  abandoned  in  favor  of  powder,  and 
the  mass  was  blasted  out  as  if  it  had  been  a  rock.     In  digging  a  well  at 
the  residence  of  the  late  President  Clark  it  was  also  necessar}^  to  blast 
in  the  same  deposit.     Masses  of  the  till  brought  up  from  a  depth  of  55 
feet  from  the  well  sunk  at  the  first  house  south  of  the  Amherst  College 
o-rounds,  where  the  whole  excavation  was  in  the  typical  bowlder  clay, 
could  be  trimmed  into  hand  specimens  with  the  hammer  while  still  fresh, 
and  broke   with  a  smooth,  broad  conchoidal  fracture,  like  flint,  and  pro- 
jecting  pebbles  would  be   broken  by    a   blow  without  being  dislodged 
from  then-  places.     Near  the  bridge  in  Leeds  an  excavation  made  several 
years  ago  exposed  a  vertical  wall  30  to  40  feet  high,  and  it  has  since 
scarcely  crumbled  at  all.     The  deep  raih-oad  cutting  south  of  Leeds  and 
the  steep  eastern  bank  of  the  river  at  that  place  are  also  good  examples  of 
its  durabihty.     It  is  chai-acteristic  of  the  valley  di-ift  no  less  than  of  the 
upland  drift  already  described  that  it  is  a  wholly  amorphous  and  unstrati- 


THE  TILL.  539 

tied  (l(>|)osit,  iind  one  needs  only  to  exjunine  n  Iresli  exposm'e  of  it  and  see 
how  all  its  parts  are  thrown  together  in  confusion,  without  any  assorting- 
accordino-  to  the  weight  and  size  of  the  stones — here  a  large  bowlder 
])rojecting,  there  many  small  ones  grouped,  and  again  over  broad  surfaces 
the  dark-gray  compacted  clay  occurring  almost  free  from  stones  of  con- 
siderable size  and  lacking  all  signs  either  in  the  color  or  the  grain  of  a 
lamination  or  an  assortment  into  parallel  layers — one  needs  only  to  make 
these  observations  and  then  for  comparison  examine  the  clay  banks  or  sand 
and  gravel  beds  so  well  exposed  in  the  river  banks,  remembering  that  they 
are  instructive  only  in  a  somewhat  fresh  exposure,  to  be  convinced  that  all 
the  characteristics  of  water  action — the  delicate  sorting  and  arranging,  like 
with  like,  according  to  size  and  weight — are  here  markedly  absent,  and  that 
it  is  quite  impossible  to  explain  the  bed  as  formed  in  this  way. 

If  one  has  reached  this  conclusion  by  carefully  compai'ing  the  two 
formations  and  has  the  opportunity  to  examine  many  sections  of  the  drift 
where  it  is  a  fine  sandy  clay,  he  will  be  almost  startled  to  find  isolated 
patches  which  seem,  to  show  a  true  and  delicate  lamination — a  series  of  fine, 
horizontal,  parallel  fissures,  a  few  millimeters  apart,  usually  gently  undu- 
lating. At  times  the  undulations  of  adjoining  lines  meet  at  equidistant 
points  like  a  flat-meshed  net,  or  like  the  cleavage  of  hornblende,  so  that  the 
clay  is  separated  into  a  bundle  of  flat,  sharp-edged  blades.  These  lines 
fade  away,  however,  in  all  directions  into  the  general  formless  mass,  and 
constitute  not  a  lamination  in  the  technical  sense — a  result  of  deposition 
in  water — but  a  pressure  cleavage  caused  by  the  same  force  which  had 
compacted  the  whole  stratum.  The  effect  of  considerable  pressure  in 
producing  cleavage,  or  a  tendency  to  split  at  right  angles  to  the  direction 
of  the  force  applied,  may  be  seen  in  a  variety  of  instances,  and  its  recog- 
nition has  thrown  light  upon  important  problems  of  geology,  such  as 
the  delicate  banding  of  glacier  ice  and  the  smooth  splitting  of  roofing 
slates.  Gun-cotton  pressed  into  cakes,  or  thick  pasteboard  calendered  under 
heavy  pressure,  may  be  separated  easily  into  thin  layers,  and  even  the 
splitting  of  a  common  cracker  or  the  flaking  of  pastry  is  a  structure  pro- 
duced by  the  pressure  of  rolling  out  the  dough  and  developed  afterwards  in 
the  baking.  This  structure  was  well  seen  in  the  waterworks  ditch  opposite 
Phoenix  Row  in  Amherst,  and  in  the  canyon  of  Deerfield  River  through  the 
divide  i-ange,  described  in  the  first  section  of  Chapter  XV,  p.  509. 


540  GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

In  another  way,  though  rarely,  the  till  may  simulate  the  bedding  of 
sedimentary  deposits,  where  it  is  thickened  into  dome-shaped  drumhns,  and 
it  will  be  seen  later  on  that  these  are  common  in  the  valley.  I  have  once 
or  twice  seen  a  rude  separation  into  thick,  irregular  layers  molded  into  each 
other  and  distinguishable  only  in  a  view  of  a  broad  surface  at  a  distance. 
This  occurs  at  the  section  mentioned  at  the  bridge  in  Leeds.  It  would  seem 
that  the  ice  pushed  one  layer  after  another  into  the  accumulating  mass  and 
so  gradually  built  it  up. 

In  the  foregoing  discussion  of  the  various  phenomena  of  the  valley 
drift  I  have  assumed  its  siibglacial  origin,  though  many  of  the  details  per- 
haps would  fit  equally  well  with  the  idea  that  the  mass  was  pushed  out 
from  the  front  of  the  ice  as  it  retreated  northward  with  various  oscillations. 
The  great  compactness  of  the  whole  and  the  pressure  cleavage  would  hardly 


.  .     ^Safla/sfv/)*rW/Wistr/ateaLsiJrfacf 

IVater/eveJ  be/oiv  c/sm     |        cont/nuedont/iesurfaceoff/tet/'/la-^ob. 
'Ground  moraine  lof^^r. 


-G.  31— Section  on  the  left  bank  of  the  Mill  Elver  at  tlie  hoe  factory,  N'orthampton,  taken  after  the  washout  of 
1878,  which  carried  the  dam  away,  showing  the  striae  on  the  surface  of  sandstone  continued  on  the  surface  of  the  till  below. 

be  explicable  upon  this  assumption,  and  I  have  now  to  describe  two  sections 
which  render  it  certain  that  the  whole  mass  is  of  subglacial  formation. 

On  the  night  of  December  10,  1878,  the  Mill  River,  flooded  by  the 
very  abundant  rains  and  by  the  breaking  away  of  several  dams  on  its  head- 
waters, rose  in  Northampton  to  a  height  greater  than  on  the  occasion  of  the 
flood  of  May  16,  1874,  which  caused  so  great  a  loss  of  propei'ty  and  life, 
and  was  less  destructive  only  because  the  earlier  flood  had  done  its  work 
so  thoroughly.  It  carried  away  the  western  part  of  the  dam  at  the  hoe 
factory  in  Northampton  and  wore  deejDly  into  the  western  bank,  exposing 
the  section  seen  in  fig.  31. 

The  dam  had  been  built  on  a  reef  of  coarse  red  sandstone  which  ran 
diagonally  across  the  stream  from  northwest  to  southeast,  the  stream  flowing 
here  from  north  to  south,  and  the  section  runs  in  the  latter  direction.     The 


THE  TILL.  541 

surface  of  the  saiulstoiie  is  rounded  and  retains  everywhere  the  glacial 
scratches  perfectly.  These  are  broad,  deep  grooves,  uniformly  directed 
S.  30-40"  E.  On  the  south  side  the  sandstone  was  uneven  and  ended 
abruptly  in  a  nearly  vertical  wall,  against  which  rested  a  mass  of  dark-gray 
till  of  stony  compactness,  the  surface  of  which  was  an  exact  continuation  of 
the  broad,  convex,  striated  surface  of  the  sandstone,  showing  that  the  ice  had 
passed  over  them  both  together  and  planed  them  down  to  a  common  level. 
Ao-ain,  in  changing  the  grade  of  the  Canal  Railroad,  near  the  South 
street  bridge  in  Northampton,  a  section  was  exposed  where  the  compact 
stony  clay  abutted  on  the  east  against  the  red  sandstone,  continuing  the 
curvature  of  the  convex  roche  moutonnde  surface  of  the  sandstone  in  the 
same  way.  In  each  case  the  drift  and  the  sandstone  were  covered  by 
the  Champlain  clays  in  such  a  way  as  to  show  that  the  exact  surface  of  the 
drift  upon  which  the  ice  rested  had  been  covered  with  the  clays  immediately 
after  the  disappearance  of  the  latter,  a  point  I  have  developed  more  fully  in 
discussing  the  clays  and  their  relation  to  the  valley  drift  at  the  beginning  of 
Chapter  XX. 

THE   COARSE   VALLEY   DRIFT. 

On  the  west  side  of  the  river  in  Northampton  the  bay  formed  by  the 
retreat  westward  of  the  crystalline  rocks  is  much  deeper,  the  drift  accu- 
mulated there  is  more  abundant,  and  the  drumlins  are  on  a  larger  scale. 
The  deposit  is,  however,  much  more  masked  by  the  later  accumulation  of 
sand  in  the  flood  period,  by  which  the  whole  surface  is  brought  up  to  the 
level  of  the  highest  terrace.  While  the  deposit  is  probably  the  exact 
equivalent  of  the  valley  drift  already  described  from  the  east  side  of  the 
river,  I  have  thought  it  best  to  describe  it  separately,  both  because  it 
occurs  in  a  separate  portion  of  the  basin  and  because  it  presents  several 
points  of  difference  when  compared  with  that. 

While  the  paste  is  clayey  and  well  compacted,  it  is  generally  much 
coarser,  bowlders  above  a  foot  in  length  often  making  up  three-fourths  of 
the  mass,  and  masses  above  3  or  4  feet  in  length  being  in  places  very 
abundant.  The  three  outcrops  already  described  in  the  preceding  section 
from  the  west  side  of  the  river  agree  in  their  fineness  and  exceeding  com- 
pactness with  the  fine  valley  drift  with  which  they  are  associated,  and,  like 
it,  certainly  rest  directly  upon  the  older  rocks.  I  have  not  been  able  to 
ascertain  if  this  was  the  case  with  regard  to  the  coarse  valley  drift  here 


542  GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

under  discussion.  The  latter  differs  from  the  former  also  in  the  origin  of 
its  material.  On  the  east  the  bowlders,  except  the  abundant  far-traveled 
quartzites,  are  mostly  fi'om  Mount  Toby  and  the  granite  south  of  it.  I 
have  rarely  found  a  piece  of  the  spangled  mica-schist  of  the  great  western 
range,  although  the  bowlders  of  2:)silomelane  and  yellow  cavernous  jasper 
found  across  Amherst  seem  certainly  to  have  come  from  the  locality  in 
Conway  on  the  northwest.  On  the  west  all  the  rocks  to  the  north  and  west 
are  abundantly  represented  by  large  bowlders,  and  very  large  masses  of  the 
Vermont  quartzites  are  also  abundant ;  one  taken  from  near  D.  Denniston's 
now  adorns  the  old  Whitney  homestead,  on  King  street,  in  Northampton, 
and  is  about  6  feet  in  diameter.^  I  have  been  inclined  to  connect  the  excep- 
tional coarseness  and  abundance  of  the  subglacial  debris  gathered  here  with 
the  peculiar  direction  of  motion  impressed  upon  the  lower  portion  of  the  ice 
by  the  trend  of  the  great  valley.  As  the  ice  moved  toward  the  valley  from 
the  northwest  it  came  upon  its  western  rim  well  charged  with  bowlders 
from  the  area  it  had  crossed,  and  was  below  deflected  southward  by  the 
trend  of  the  valley,  and  still  farther  deflected  to  the  west  of  south  and 
obstructed  by  the  transverse  Holyoke  range,  and  its  morainic  material  was 
gathered  in  a  sort  of  eddy  under  the  western  cliffs  or  swept  southward  in 
the  valley,  and  so  failed  to  reach  the  eastern  side  of  the  basin. 

DISTRIBUTION   OF   THE   COARSE   VALLEY   TILL   WEST   OF   THE   RIVEE. 

The  most  northerly  exposure  of  the  bowlder  clay  in  the  river  side  is  at 
the  westernmost  point  of  the  great  Hadley  bend,  where  the  river  has  worn 
into  it,  and  the  bowlders,  accumulating  upon  the  shore,  have  formed  a  natural 
"riprap"  and  thrown  the  current  across  against  the  Hadley  side,  where  it 
will  in  time  cut  off  the  point  of  the  bend  and  leave  its  present  channel. 

This  exposure  seems  to  be  the  northern  end  of  a  long  ridge  or  series  of 
drumlins  which  runs  in  a  general  way  southward  across  Northampton, 
mostly  covered  by  the  later  sands.  It  is  exposed  on  Slough  Hill,  west  of 
the  north  end  of  King  street,  and  deeply  cut  into  by  the  Canal  Railroad  at 
the  Black  Pole  bridge.  Its  further  prolongation,  Round  Hill,  is  a  mass- 
ive drumlin.  Under  the  Forbes  Library,  Smith  College,  and  the  asylum 
the  bowlder  clay  rises  to  the  surface  and  reaches  just  the  same  level  as  the 
surrounding  sands  which  form  the  level  surface  of  Elm  street.     These  two 

'It  has  been  placed  over  the  grave  of  Prof.  Josiah  D.  Whitney,  late  professor  of  geology  in 
Harvard  University. 


THE  TILL.  543 

liills  (if  drift  are  separated  to  tlie  depth  of  the  present  bed  of  Mill  River, 
as  is  shown  by  the  height  of  the  bowlder  clay  in  the  section  at  the  hoe 
factory,  ah-eady  described.  West  of  the  asylum  Sunset  Hill  and  the  long 
wooded  hills  between  which  runs  the  road  to  Loudville  form  the  most 
elevated  and  extensive  accumulation  of  drift  in  the  valley.  The  first  of 
these  hills,  starting  from  the  northwest  corner  of  the  asylum  grounds,  runs 
southwesterly  and  is  continned  across  the  Loudville  road  by  the  higher  and 
more  massive  hill  which  is  conspicuous  at  a  distance  from  the  number  of 
great  bowlders  of  whitened  quartz-diorite  (tonalite)  that  cover  the  broad 
benches  on  its  southeastern  side.  The  road  to  Easthampton  skirts  this 
hill  for  a  long  distance  on  its  southern  side,  and  the  sands  of  the  high 
terrace  abut  upon  its  other  slopes. 

This  completes  the  chain  of  ridges,  and  a  glance  at  the  map  will  show 
how  they  are  swung  in  a  broad  curve,  from  Elizabeth  Rock  to  the  West- 
hampton  Hills,  across  the  mouth  of  the  deep  bay  formed  by  the  recession 
of  the  crystalline  rocks.  Within  this  bay  two  other  prominent  drumlins 
take  the  same  west-of-south  direction — the  wooded  hill  east  of  Florence 
and  the  long  steep  elevation  above  Bay  State  on  the  north.  And  finally, 
all  the  broad  wooded  area  west  of  Mill  River  opposite  Bay  State  is  a  con- 
tinuous tmdulating  ai'ea  of  bowlder  clay,  and  from  a  point  below  Florence 
nearly  all  the  way  to  the  asylum  Mill  River  is  wearing  into  it,  and  its 
western  bank  is  covered  with  abundant  bowlders  from  which  the  stream 
has  washed  out  the  finer  material,  and  here  are  the  best  permanent  sections 
m  the  bowlder  clay  to  be  found  in  the  valley. 

Farther  south,  across  Southampton  and  Westfield,  the  Champlain 
sands  occupy  the  greater  portion  of  the  valley  bottom,  and  where  the  till 
appears  it  is  usually  with  an  undulating  surface  and  is  made  up  of  rather 
fine-grained,  reddish  material,  derived  mainly  from  the  red  sandstone,  very 
compact,  with  bowlders  nearly  all  under  1  foot  in  greatest  length,  and 
thus  is  very  different  from  the  upland  till.  This  is  notably  the  case  in  all 
the  west  half  of  Southwick. 

DRUMLINS. 

Perhaps  the  most  notable  contribution  to  science  made  by  the  Second 
Geological  Survey  of  New  Hampshire  was  the  recognition  of  this  interesting 
and  peculiar  form  of  drift  hills,  coupled  as  it  was  with  a  careful  mapping  of 
their  distribution  and  a  satisfactory  explanation  of  their  origin. 


544  GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

The  credit  due  for  this  piece  of  excellent  original  work  is  certainly 
not  impaired  by  the  fact  announced  by  Prof.  W.  M.  Davis,  in  his  historical 
rdsumd  of  the  literature  of  the  subject,^  that  the  same  forms  had  been 
observed,  mapped,  and  correctly  explained  by  Mr.  M.  H.  Close,^  in  Ireland, 
at  an  earlier  date.  As,  moreover,  the  name  "lenticular  hills,"  proposed  by 
Messrs.  Hitchcock  and  Upham,  is  certainly  not  a  very  satisfactory  one,  and 
seemed,  indeed,  not  wholly  satisfactory  to  its  authors,  it  is  a  matter  of  con- 
gratulation that  the  earlier  paper  proposes  a  name  from  the  Irish,  which, 
with  the  Scotch,  is  so  much  richer  in  names  for  the  varieties  of  surface 
form  of  the  land  than  is  our  own  dialect.  Indeed,  if  the  word  could  come 
into  general  use  it  would  be  a  valuable  addition  to  our  synonyms  for  hill 
forms,  while  its  more  precise  use  follows  a  custom  already  set  in  this 
department  of  study. 

The  comparison  of  drumlins  with  the  sand  banks  formed  beneath 
flowing  water  seems  quite  satisfactory.  I  have  also  been  interested  to 
compare  them  with  roches  moutonndes,  with  which  they  are  associated  in 
origin  beneath  the  ice. 

Fig.  31,  p.  540,  is  a  representation  of  a  vertical  bank  of  clay  and  till 
resting  against  red  sandstone.  A  broad  roche  moutonnee  of  the  red  sand- 
stone, beautifully  striated,  was  exposed,  and  abutting  against  the  southern 
vei'tical  and  unstriated  wall  of  the  rock  was  a  till  of  almost  equal  com- 
pactness with  the  rock  itself,  bounded  above  by  a  curved  surface,  which 
was  the  exact  continuation  of  that  of  the  sandstone.  The  curve  sank 
under  the  water  above  and  below.  This  may  with  some  propriety  be 
called  half  roche  moutonnee  and  half  drumlin,  and  illustrates  the  close 
similarity  of  the  cause  originating  the  two  rock  forms — the  differential 
pressure  of  the  ice  upon  its  substratum.  In  several  other  cases  rock  takes 
part  in  the  formation  of  the  drumlin,  at  times  as  a  nucleus  with  steeper 
slopes  than  those  of  the  drumlin  itself,  but  appearing  along  its  crest;  yet 
this  is  the  exception  here  as  elsewhere. 

The  distribution  of  these  hills  along  the  valley,  as  shown  in  PL 
XXXV,  is  interesting,  and  may  throw  some  light  upon  the  question  of  the 
north-south  motion  of  the  ice  in  the  valley  as  compared  with  the  northwest- 
southeast  motion  on  the  higher  ground  on  either  side. 

1  Am.  Jour.  Sci.,  3d  series,  Vol.  XXVIII,  1884,  p.  407. 

2  Jour.  Royal  Geol.  Soc,  Ireland,  1886,  p.  1207. 


DRUMLINS.  545 

If  one  could  remove  ;ill  the  newer  deposits — sands  and  t-luy.s — which 
still  await  our  discussion,  and  then  raise  this  great  stratum  of  stony  clay 
which  overspreads  the  valley,  as  one  lifts  a  plaster  mask  from  the  face,  it 
would  be  found  that  its  under  surface  had  been  exactly  molded  to  every 
line  and  curve  of  the  rocky  substratum;  but  its  upper  surface  would  have 
the  effect  of  a  comic  mask,  swelling  with  unequal  thickness  over  every 
prominent  feature,  distorting  and  concealing  its  true  form,  and  sending  up 
great  protuberances  due  wholly  to  a  thickening  of  its  own  mass  and  not 
molded  on  any  projecting  ledge  below.  The  protuberances  formed  thus 
by  the  local  thickening  of  the  drift  sheet  appear  now  as  dramlins — massive 
domed  hills,  in  shape  like  an  inverted  canoe,  with  the  long  axis  pointing  in 
the  direction  of  the  glacial  motion,  from  north  to  south.  Where  they  are 
most  symmetrical  they  slope  away  rapidly  and  equally  toward  the  east 
and  west,  more  gradually  but  equally  north  and  south,  and  very  naturally 
suggest  the  name  "hogbacks,"  by  which  they  are  often  known  inland,  or 
"whalebacks,"  as  they  are  called  near  the  sea.  They  rise  hke  islands  out 
of  the  sands,  which  wrap  around  their  bases  to  a  maximum  height  of  150  to 
200  feet  above  the  present  low  ground  of  the  valley,  and  often  the  thick- 
ness of  the  till  composing  them  seems  to  be  greater  than  that. 

The  two  hills  just  north  and  south  of  the  village  of  South  Amherst 

named  Castor  and  Pollux  by  President  Hitchcock,  from  their  close  simi- 
larity— another  to  the  east  of  the  former,  and  two  others  farther  south  and 
west,  are  all  cast  in  the  same  mold.  Farther  north  the  hill  south  of  Col- 
lege Grove— named  the  Occident  by  President  Hitchcock— the  College  Hill, 
and,  finally,  all  the  group  of  hills  occupying  the  space  between  Amherst, 
East  Street,  and  North  Amherst  villages  are  of  the  same  origin  and  pre- 
serve in  varying  degrees  the  common  form. 

In  the  case  of  all  the  hills  around  South  Amherst,  except  Castor,  there 
are  no  neighboring  outcrops  by  which  one  can  judge  of  the  elevation  of  the 
subjacent  ledges  and  so  fix  the  thickness  of  the  drift  stratum  forming  the 
hill.  The  surface  of  the  rock  may  be  concave  beneath  them  and  the  thick- 
ness of  the  till  much  greater  than  their  height  above  the  valley  bottom.  In 
Castor  the  gneiss  and  granite  appear  high  up  on  the  shoulder  of  the  hill  on 
the  east  and  the  west,  and  if  it  runs  under  the  drift  at  the  same  level  the 
thickness  of  the  latter  would  be  about  30  feet,  which  is  probably  more  than 
the  real  thickness. 

MON  XXIX 35 


546  GEOLOGY  OF  OLD  HAMPSHIEE  COUJSTTY,  MASS. 

The  ledg-e  seems  to  me  to  be  very  deep  below  the  surface  of  the  Occi- 
dent, the  hill  south  of  College  Grrove,  but  no  certain  data  are  attainable. 
The  well  on  the  east  slope  of  this  hill  at  R.  W.  Greene's  was  sunk  in 
"hardpan"  46  feet,  as  he  informed  me.  In  the  College  Hill  the  Octagon 
cellar  showed  that  the  surface  was  the  true  till  The  college  well  is  25  feet 
deep,  and  about  45  feet  below  this  the  well  already  mentioned  was  sunk 
55  feet,  and  another  on  the  southwest  slope  of  the  hill,  at  the  east  end  of 
Short  street,  was  sunk  to  the  same  depth,  giving  the  till  an  ascertained 
thickness  of  100  feet,  and  the  whole  thickness  is  certainly  much  greater. 

The  high  lull  north  or  northwest  of  East  Street  has  in  perfection  the 
form  of  a  drumlin,  and  is  doubtless  of  common  origin  with  those  already 
described.  There  is,  however,  at  its  top  a  broad  expanse  of  red  sandstone, 
which  appears  nowhere  upon  its  slopes,  either  at  the  surface  or  in  wells.  It 
has,  therefore,  a  nucleus  of  rock  of  different  configuration  and  with  sharper 
slopes  than  the  present  hill.  Between  the  Center  and  North  villages,  finally, 
and  bounded  on  the  west  by  the  road  and  on  the  east  by  the  railroad 
between  these  places,  is  a  group  of  these  hills,  so  blended  that  the  symmetry 
is  somewhat  lessened,  in  which  different  summits  resemble  the  several  hills 
already  described.  Under  the  hill  on  which  Professor  Tyler's  house  is 
built,  and  its  prolongation  eastward,  the  red  sandstone  is  everywhere  near 
the  surface  and  the  till  is  thin. 

West  of  Mount  Pleasant  the  gneiss  is  near  the  surface;  it  is  50  feet 
below  the  surface  under  the  house  at  the  south  end  of  Mount  Pleasant,  and 
rises  to  the  surface  a  few  rods  north  of  the  site  of  the  residence  of  the  late 
President  Clark.  An  examination  of  the  map  will  make  it  plain  that  these 
hills  rest  upon  a  concealed  ridge  of  older  rocks  running  south  and  a  few 
degrees  west  of  south  from  North  Amherst  City  to  South  Amherst,  and  that 
they  lie  in  the  lee  of  the  high  ground  consisting  of  crystalline  rocks  which 
projects  westward  north  of  the  former  village,  and,  finally,  that  there  is  a 
close  similarity  in  the  arrangement  of  the  drumlins  on  both  sides  of  the 
river,  those  on  the  west  lying  in  a  line  curving  to  the  westward  and  in 
the  shadow  of  the  projecting  heights  of  Elizabeth  Rock,  as  described  in  the 
preceding  section. 

The  most  striking  series  of  drumlins  in  the  valley  is  found  in  Bernards- 
ton  and  Gill.  They  are  of  the  largest  size  and  of  most  symmetrical  form. 
A  fine  view  of  them  may  be  had  from  the  railway  in  Northfield  village. 


DEUMLINS.  547 

across  the  river  U)  the  west.  They  cover  the  first  range  of  hills  above 
tlio  highest  ten-ace  and  rise  one  behind  the  other,  their  long,  curving  lines 
overlapping  re]ieatedly  and  forming  an  ideal  drumlin  landscape.  Standing 
on  top  of  the  tallest  of  these  hills  east  of  the  village  of  Bernardston  and 
lookin"-  southward,  one  can  see  the  train  of  drumlins  crossing  the  plain, 
where  they  are  in  part  submerged  in  the  Champlain  sands,  and  then  rising 
high  upon  the  great  mass  of  Triassic  sandstone  which  forms  the  town  of 
Gill,  though  not  reaching  its  top.  The  surface  of  the  sandstone  beyond 
and  higher  up  is  molded  into  drumlin-like  forms.  Descending  the  south- 
ward slopes  of  the  sandstone  mass,  or  following  the  eastward  side  of  the 
valley  southward,  one  finds  no  drumlins  except  a  single  small  but  well- 
formed  one  beside  the  railroad  just  north  of  the  station  in  Whately.  Nor 
is  any  trace  of  them  to  be  seen  north  of  or  up  the  north  slope  of  Mount 
Toby,  which  holds  a  situation  in  the  valley  quite  similar  to  the  Grill  mass. 

It  is  a  peculiarity  of  these  hills  in  Bernardston  that  while  they  in 
many  places  obscure  the  geology  of  the  region  fatally,  the  interspaces  are 
over  considerable  areas  almost  driftless,  so  that,  outside  the  regular  oval 
base  of  the  hill,  fragments  on  the  surface  are  quite  safe  indications  of  the 
ledges  which  lie  but  a  little  distance  below. 

As  indicated  upon  the  map  the  boundary  of  the  crystalline  rocks 
wMcli  form  the  western  border  of  the  valley  follows  the  east  line  of  Ber- 
nardston near  the  river  and  then  turns  west  along  the  south  line  of  that 
town  and  Leyden,  and  again  south  along  the  west  line  of  Greenfield, 
Deerfield,  and  Whately,  to  Northampton,  where  it  is  again  set  back  by  the 
width  of  the  latter  town,  and  runs  thence  southerly  to  the  south  line  of 
the  State.  Along  this  sloping  border  of  the  valley  between  Greenfield  and 
Northampton  runs  a  train  of  drumlins,  some  having  their  bases  nearly  100 
feet  above  the  level  of  the  high  terrace  sands  (Northampton  high  terrace 
305  feet,  Greenfield  357  feet,  above  sea),  while  others  are  more  or  less 
submerged  in  these  sands;  indeed,  in  several  cases  wholly  submerged  and 
beautifully  regular  drumlins  have  been  exposed  in  the  extensive  railroad 
cuttings  up  this  side  of  the  valley.  In  one  most  interesting  case  at  the 
Camp  Meeting  cutting  on  the  north  line  of  Northampton  (see  PI.  XV), 
what  seemed  to  be  a  broad  terrace  of  coarse  sand  contained,  to  the 
dismay  of  the  contractors,  a  fine  drumlin  of  rocky  hardness  which  had 
to  be  blasted  away  in  front  of  the   steam  shovel,  and  was  capped  by 


548  GEOLOGY  OF  OLD  HAMPSHIEB  COUNTY,  MASS. 

three  later  glacial  deposits  with  as  many  intervening  sands,  which  could  be 
followed  for  3,350  feet  in  the  open  cutting. 

Several  of  these  hills  of  most  regular  shape  are  so  built  up  on  the 
steeply  sloping  rocky  valley  side  (the  valley  runs  here  north  and  south) 
that  looking  up  from  below  one  seems  to  have  before  one  a  drumlin  of  the 
largest  size,  while  looking  down  from  higher  up  the  hillside  one  sees  only 
a  small  ridge  interrupting  the  eastward  slope.  These  hills  are  directed 
southerly,  as  are  the  neighboring  strise,  but  they  He  near  the  western 
boundary,  between  the  areas  of  southeast  and  of  southern  motion  of  the 
ice,  like  a  line  of  bars  between  two  currents  meeting  from  different  direc- 
tions; and  in  Northampton,  where  the  ice  was  deflected  in  the  valley 
southwestward,  the  drumlins  have  the  same  direction  and  swing  in  a  great 
curve  across  the  reentrant  angle  in  the  rocky  border. 

In  the  town  of  Amherst  nearly  every  hill  is  a  drumlin,  and  in  several 
cases  they  are  laid  side  by  side  in  pairs  and  coalesce  laterally.  It  is  fur- 
ther interesting  that  this  group  of  drumlins  in  Amherst  runs  right  up  to  the 
steep  northern  base  of  the  Holyoke  range,  which  here  traverses  both  the 
valley  and  the  direction  of  the  ice,  and  whose  crest  of  trap  is  finely  covered 
with  north-south  striae. 

I  have  mentioned  above  that  the  drumlin  exposed  in  the  Camp 
Meeting  cutting,  a  little  higher  in  the  valley,  is  covered  by  three  sepa- 
rate glacial  beds,  representing,  doubtless,  as  many  oscillations  in  the  ice 
at  the  time  of  its  retreat,  which  shows — what,  indeed,  hardly  admitted 
of  doubt — that  the  drumlins  were  formed  beneath  the  thick  ice  of  the 
general  glaciation;  and  the  position  of  this  last  group,  carried  with  north- 
south  axes  right  up  to  the  foot  of  the  steep  Holyoke  range,  which  itself 
is  striated  in  the  same  direction,  bears  strong  evidence  against  the  exist- 
ence of  a  separate  Connecticut  Eiver  glacier  which  should  explain  the 
north-south  striation  of  this  valley.  Indeed,  these  north-south  drumlins 
are  carried  up  so  high  on  the  sides  of  the  valley  that  when  one  imagines 
ice  of  the  smallest  thickness  needful  to  build  them  and  compress  them  to 
their  present  rock-like  density,  one  sees  that  the  ice  would  have  risen 
above  the  boundaries  of  the  valley  and  have  overflowed  fan-like,  as  in  the 
great  lobes  found  in  the  Western  States.  The  facts  seem,  then,  to  accord 
better  with  the  theory  proposed  by  Professor  Dana  of  a  differential 
motion  of  the  lower  portion  of  the  ice  in  the  valley,   and  the  long  line 


MORAINES  AND  BOWLDER  TRAINS.  549 

of  flrumlins  carried  down  the  western  border  of  the  valley  mark  the  line 
alon<>-  wliicli  the  ice  was  deflected  southwardly  into  its  new  direction. 
South  of  the  Holyoke  range  and  east  of  the  Mount  Tom  range  the  drum- 
lins  are  broader,  flatter,  and  fewer  in  number  than  farther  north. 

On  the  hills  east  and  west  of  the  valley  drumlins  are  rare  oi  wanting. 
I  have  noted  only  one  train — this  of  hills  of  the  largest  size — which  enters 
the  northwest  corner  of  Blandford  from  Becket,  with  direction  S.  35°  E. 
A  very  fine  one  is  situated  a  little  southwest  of  the  center  of  Granville. 

MORAINES    AND    BOWLDER    TRAINS. 

The  great  ridge  of  bowlders  of  tonalite  which  passes  the  Catholic  church 
in  Thorndike  and  extends  southwardly,  going  to  the  west  of  the  group  of 
high  hills  southwest  of  this  village  and  appearing  in  exceptional  force  near 
E.  Brown's  house,  just  west  of  Palmer  village,  and  crossing  the  river  to  mount 
the  high  hill  just  south  (Bald  Peak,  in  Monson),  is  a  portion  of  a  true  ter- 
minal moraine  of  a  lobe  of  the  ice  which  shut  up  the  gorge  through  which 
the  Quabaug  River  passes  northwestward  from  Palmer  village,  and  fur- 
nished the  barrier  for  the  Palmer  Lake  (see  PI.  XXXV  and  Chapter  XVII). 
In  the  latter  part  of  its  course  its  bowlders  are  exclusively  of  Monson  gneiss 
and  of  very  large  size,  one  26  by  16  by  7  feet. 

From  the  large  dike  of  granite  in  the  center  of  Middlefield  a  well- 
marked  bowlder  train  is  carried  across  Chester,  passing  through  the  center 
of  the  town  and  traceable  for  a  distance  of  5  miles. 

Just  west  of  the  road  running  north  from  the  village  of  Leverett  a 
prominent  hill  of  granite  is  continued  for  a  long  distance  southward  by 
a  mass  of  bowlders  so  densely  packed  that  it  seems  like  the  continuation 
of  the  hill  itself,  and  in  the  northern  part  of  Worthington  is  a  similar 
crag-and-tail  arrangement  of  colossal  bowlders  of  mica-schist  carried 
southeast  from  a  prominent  hill,  so  closely  packed  that  one  can  jump 
from  one  to  another  for  a  long  distance. 

Stretching  southeast  from  the  great  band  of  fine-grained  granite  west 
of  Burnell's  pond  in  Chesterfield  is  an  immense  accumulation  of  large, 
often  immense,  bowlders.  It  continues  to  the  southeast  corner  of  Chester- 
field and  on  into  Westhampton. 

A  marked  bowlder  train  starts  from  ti/e  dike  of  pecuUar  porphyritic 
granite  northwest  of  Leyden  and  extends  past  the  center  of  the  town  and 
on  a  little  east  of  south  into  Greenfield. 


550  GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

Bowlders  of  the  peculiar  brown,  porous,  and  drusy  chalcedony  and 
pyrolusite  from  Conway  are  so  abundant  across  Amherst  and  Granby  as 
to  deserve  mention.  One  mass  on  the  eastern  peak  of  the  Holyoke  range 
measures  6  by  6  by  4  feet. 

THE    INTERGLACIAL    SANDS. 

An  elderly  lady  in  Amherst  says  that  when  she  first  visited  the  town 
of  Amherst  there  was  a  remai'kable  spring,  never  failing-,  near  H.  M.  Burt's 
residence,  opposite  the  A^<1>  house,  the  water  from  which  flowed  down 
eastward  across  the  common  and  into  a  quagmire  overgrown  with  alders, 
in  which  several  pigs  were  drowned  during  her  visit.  Since  then  Mr. 
Burt's  well  occupies  the  position  of  the  spring,  and  is  remarkable  for  its 
volume  of  water,  which  often  rises  to  within  2  feet  of  the  surface  at  the 
very  crest  of  the  ridge. 

Farther  north  on  the  same  ridge  the  well  at  J.  L.  Lovell's  house  is 
also  remarkable  for  its  abundant  flow  of  water,  it  being  almost  impossible 
to  empty  the  well.  Again,  in  lowering  the  Northampton  road  opposite 
College  Hall  in  1878  a  layer  of  yellow  stratified  sands,  the  finest  0.3  to 
0.6™™,  the  coarsest  0.5  to  1™™  in  grain,  from  6  inches  to  a  foot  and  a  half 
thick,  much  contorted,  was  exposed,  which  was  covered  by  a  thin  layer 
(from  6  inches  to  a  foot  and  a  half  in  the  section,  but  rising  to  a  greater 
thickness  farther  north)  of .  a  hard,  blue  till  and  underlain  by  an  ashy  till 
carrying  many  striated  bowlders,  one  mass  of  conglomerate  being  3  feet 
long.  The  sand  layer  continued  to  both  ends  of  the  section,  about  5  rods. 
The  same  section  occurred  at  two  excavations  farther  north  on  the  same 
ridge,  on  the  grounds  of  Mrs.  Davis  and  William  W.  Hunt.  I  did  not  con- 
nect these  facts  or  find  suitable  explanation  for  them  until  I  had  studied  the 
exceptionally  interesting  section  furnished  by  the  digging  of  the  Amherst 
House  cellar. 

In  digging  the  cellar  a  block  of  earth  92  by  104  feet  and  12  feet  deep 
was  removed,  and  at  the  same  time  the  ditches  of  the  Amherst  waterworks 
were  opened,  having  a  depth  of  from  5  to  8  feet  and  extending  from  a  point 
just  in  front  of  the  cellar  eastward  to  the  dam  in  Pelham,  a  distance  of 
nearl)^  3^  miles,  a  mile  north  to  the  Plant  House,  1,400  feet  south  to  the 
railway  station,  and  1,200  feet  west  to  the  brow  of  the  hill  on  Amity  street. 

The  cellar  section  is  illustrated  by  the  figures  of  PI.  XII,  drawn  care- 
fullv  to  true  scale.     Fig.  1  is  taken  from  the  northeast  corner  of  the  cellar. 


12 


U.  S.  GEOLOGICAL  SURVEY. 


MONOGRAPH  XXIX.  PL.  XII. 


^■■. 

^r""^^^- 

I                "■■^••\~': 

■  ' 

4  '=.  :.;i4?a,v 

':    D 

''-> 

^'  ■■■■■/ 

f*^:-. 

.-^-^^ 

r::>  - 

CLAV  FILLING  ^^...^^^ 
OF  CREVICE     ^^ 
3 


5.  THIRD  TILL. 

4,  SECOND   SAND. 

3  SECOND    TILL. 

2.  INTEROLACIAL    SAND. 

I.  LOWER    TILL. 


8CRATCHED 
BOWLDERS. 


SECTIONS  OF    AMHERST    HOUSE    CELLAR,   SHOWING    INTERGLACIAL  BEDS. 


INTEIIGLACIAL  SANDS.  551 

lookiii"-  soutliwc'stward  The  lowest  stratum  (1)  i)resent  is  the  lowest  till  or 
vallc>'  drift,  which  forms  the  floor  of  the  cellar  and  is  seen  rising  to  the  sur- 
face in  the  south  wall  (fig.  2).  It  forms  all  the  remainder  of  the  south, 
all  the  east,  and  nearly  all  the  north  wall  (fig.  6);  and  in  the  waterworks 
ditches  which  radiated  from  this  point  it  occupied  the  whole  depth  for  a 
thousand  feet  north,  south,  and  east;  and  to  the  west,  where  the  ditch  ran 
parallel  to  the  north  side  of  the  cellar,  it  repeated  exactly  the  section 
developed  in  the  latter  (fig.  6).  The  ground  here  is  311  feet  above  tide, 
and  slopes  away  in  all  directions,  so  that  the  till  soon  sank  under  the  highest 
stratified  deposits  of  the  subsequent  flood  period,  which  reached  here  nearly 
300  feet  above  tide.  Above  this  level  it  had  never  been  covered,  and  the 
boundary  of  the  till  traced  upon  the  map  represents  only  the  uncovered 
part.  The  bottom  of  the  deposit  is  here  nowhere  exposed,  but  farther  east, 
opposite  the  old  Amherst  Bank  building,  the  New  Red  sandstone  comes  to 
the  surface  and  has  this  till  on  its  back,  and  farther  north  the  gneiss  does  the 
same  at  the  entrance  to  the  Agricultural  College  farm,  and  in  both  cases  the 
stratum  has  shrunk  to  a  foot  in  thickness.  The  cellar  deposit  has  already 
been  made  the  type  of  the  detailed  description  of  the  valley  di-ift  (page  537). 
Upon  this  base  rests  a  layer  of  stratified  sand  (2)  5  feet  thick,  upon  this  a 
bed  of  compact  till  (3)  1  to  IJ  feet  thick,  next  1  foot  of  sand  (4),  and  the 
whole  is  capped  with  a  7-foot  bed  of  till  (6). 

The  lower  sands  (2)  were  deposited  immediately  upon  the  irregular, 
hummocky,  apparently  eroded  surface  of  the  till,  the  lowest  layers,  some- 
times gravelly,  folding  over  smaller  irregularities  and  projecting  bowlders 
and  gradually  obliterating  the  depression.  The  upper  and  larger  portion 
was  cross-stratified  on  a  large  scale,  the  laminae  dipping  west  from  5°  to  40°, 
and  where  the  structure  was  least  disturbed  a  high  dip,  about  30°,  pre- 
dominated. Here  and  there  a  delicate  flow-and-plunge  structure  could 
be  seen.  The  whole  stratum  consists  of  clean,  well-washed  sand,  whitish 
where  not  colored  by  a  later  infiltration  of  iron,  varying  from  a  fine  sand 
which  retains  water  and  has  an  average  grain  of  0.09""°  to  a  coarse  granitic 
sand  having  a  grain  of  0.5  to  1""°.  Thin  seams  of  gravel  separate  the  layers 
of  sand  here  and  there.  Comparing  many  samples  with  the  ordinary  sands 
which  compose  the  higher  terraces  of  the  valley,  I  found  them  to  agree 
quite  well  under  the  microscope,  but  the  glacial  sands  had  been  more 
rounded  by  attrition  in  water  and  were  better  sorted  than  the  later  flood 


552       GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

sands.     The  bed  was,  however,  everywhere  disturbed  by  the  pressure  and 
thrust  of  the  ice  which  had  moved  over  it  from  north  to  south. 

On  the  western  face  (fig.  5)  the  laminae,  which,  being  exposed  in  the 
direction  of  the  strike,  had  run  nearly  horizontally,  have  been  squeezed 
into  wavy  folds,  and  often  show  beautiful  illustrations  of  reversed  faults, 
the  upthrow  overlying  the  downthrow,  the  faults  always  dipping  to  the 
north.  On  the  southern  face  these  faults  were  much  more  numerous,  and 
as  the  work  of  removing  the  earth  progressed  they  were  constantly  chang- 
ing. On  one  face  of  10  feet  I  counted  twenty.  On  the  surface  repre- 
sented in  the  figure  they  are  present  in  great  number,  and  two  are  especially 
marked,  one  faulting  the  bed  3  feet ;  these  dip  60°  W.  In  other  portions 
the  bed  was  thrown  into  entire  confusion.  Over  a  large  portion  of  the 
section  a  beautifully  dehcate  incipient  cleavage  has  been  superinduced  in 
the  sands  by  the  pressure,  and  its  existence  is  made  manifest  only  by  the 
concentration  of  iron  rust  in  sharply  distinct  layers  1^  inches  apart,  which 
run  parallel  to  the  level  base  of  the  till  above,  passing  across  the  laminae 
of  the  sands  and  distinguishable  instantly  from  the  ordinary  lines  which 
mark  the  lower  limit  of  infiltrating  water.  Their  position  in  the  upper 
portion  of  a  thick  permeable  layer  and  beneath  an  impervious  one  would 
make  them  difficult  of  explanation  in  that  way.  It  seems  to  me  that 
the  pressure  has  produced  in  the  sands  distinct  traces  of  a  plane-parallel 
structure,  which  has  favored  the  movement  of  the  percolating  waters  in  a 
definite  plane,  and  with  this  also  the  deposition  of  the  iron  from  the  water. 
This  structure,  I  have  no  doubt,  was  produced  within  the  sands  when 
frozen. 

At  its  base  the  stratum  of  sand  is  closely  blended  with  the  till,  and 
although  the  transition  is  effected  in  the  space  of  an  inch,  there  is  no  sharp 
line  of  separation.  Above,  the  stratum  is  planed  down  to  a  horizontal  line, 
the  laminae  being  cut  sharply  across,  and  the  middle  layer  of  till  rests 
upon  the  surface  thus  produced  like  a  plank,  with  a  clearly  defined  line  of 
demarcation  between  it  and  the  sands  it  covers.     It  is  a  horizontal  fault. 

It  seems  to  me  certain  that  when  the  ice  moved  over  this  mass  of  sand, 
now  so  yielding  and  incoherent,  the  latter  was  frozen  into  a  solid  and  rocky 
mass,  and  that  it  was  thus  eroded  and  faulted  and  cleaved,  and  where  the 
freezing  was  less  entire  was  swept  into  the  common  chaos  of  the  till  above. 
In  many  cases  the  upper   layers  of  the   till  contain  well-rounded  sand 


INTERGLAOIAL  SANDS.  553 

l)(>wl(lci's  (I  iuclii's  in  greatest  diameter,  which  can  be  exphiined  only  as 
;il)ovf  'uuHcated.  They  are  now  jtockets  of  a  nuxch  flattened  elHpsoidal 
t'orni,  fiHod  with  a  l)utf  sand  hke  that  fornaing  the  layer  below. 

'I'liis  sand  stratum  was  again  finely  exposed  in  the  water-main  ditch  on 
Ainit\-  street  (a  few  rods  north),  on  a  line  running  east  and  west,  and  thus 
with  the  dip  of  the  laminse  of  the  sands.  It  rested,  as  before,  upon  the 
irregular  surface  of  the  till  below,  and  was  covered  here  and  there  by  frag- 
ments of  the  second  till,  partly  removed  in  grading  the  road.  The  sands 
were  exposed  for  a  distance  of  350  feet,  commencing  at  a  point  opposite 
the  noi'thwest  corner  of  the  cellar.  Here  they  began  as  a  thin,  gravelly 
bed,  and,  the  till  beneath  dipping  westward,  they  soon  reached  a  thickness 
of  more  than  6  feet,  and  their  whole  depth  was  not  exposed  for  60  feet. 
Then  the  till  rose  nearly  to  the  surface  for  60  feet,  and  for  the  rest  of  the 
distance  the  till  appeared  only  here  and  there  in  low  hummocks  in  the 
bottom  of  the  ditch,  until  at  last  the  sands  ran  out  to  the  surface  on  the 
slope  of  the  hill  between  the  first  and  second  layers  of  the  till,  opposite 
Professor  Crowell's  house. 

The  sands  agreed  in  all  particulars  with  those  already  described  in  th.e 
cellar  section,  presenting  the  same  gradation  from  a  fine,  whitish,  clayey 
sand  through  buff  sands  to  fine  gravel,  the  same  flow-and-plunge  structure, 
and  false  bedding  with  westerly  dips,  all  in  places  more  or  less  obliterated  in 
the  contortions  produced  in  connection  with  the  deposition  of  the  second  till. 

Again,  the  ditch  almost  continuously  cut  across  the  same  sands,  overlain 
and  underlain  by  till  and  in  places  confusedly  intermixed  with  the  second 
till,  as  it  continued  north  on  the  North  Amherst  road  up  to  the  western  base 
of  Mount  Pleasant  and  80  rods  north  of  the  cellar,  where  the  road  goes 
down  a  small  slope,  at  the  gate  of  the  Mount  Pleasant  grounds.  These 
sands  agree  exactly  with  those  before  described,  and  are  doubtless  a  con- 
tinuation northward  of  the  same  stratum  which  I  have  traced  from  College 
Hall  and  which  here  crosses  the  road  and  runs  eastward  into  Mount 
Pleasant.  What  course  it  takes  from  here  on  is  uncertain,  as  it  conforms 
itself  to  the  irregular  surface  of  the  underlying  till.  It  seems  to  me  prob- 
able that  it  rises  high  enough  toward  the  north  or  to  the  east  to  produce 
the  head  and  strong  flow  of  water  in  the  wells  on  the  ridge  mentioned 
above.  That  this  water  sets  from  the  north  to  the  south  was  shown  very 
clearly  by  the  fact  that  for  40  feet  south  of  an  old  well  which  had  been  sunk 


554       GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

under  the  former  Amherst  House  through  the  sand  stratum  (2)  and  into 
which  the  sewage  of  the  house  had  been  directed  for  many  years,  the  buff 
color  of  the  sands  was  wholly  discharged  and  the  sands  were  clotted  into  a 
greenish  mass,  and  that  this  effect  extended  southward  without  diminution 
as  far  as  the  excavation  continued.  On  the  north  the  sands  retained  their 
buff  color  up  to  the  well  itself  This  well  was  located  in  the  middle  of  sec- 
tion 5,  PI.  XII,  and  went  below  the  bottom  of  the  section.  It  was  clear  that 
the  decomposing  organic  matter  had  reduced  and  removed  the  iron  from  the 
sands  for  a  long  distance  south,  and  that  the  sands  had  thus  lost  their  power 
of  piu-ifying  the  water  which  set  southward.  A  colleague  who  had  had 
abundant  opportunity  for  judging  remarked  to  me  that  he  never  liked  the 
flavor  of  the  water  in  Mr.  Burt's  well,  located  a  few  rods  south. 

I  have  now  traced  these  sand  strata  along  the  western  slope  of  the 
ridge  which  joins  College  Hill  and  Mount  Pleasant  from  the  first  section 
northward  more  than  a  mile,  with  a  width  of  50  to  350  feet  and  a  thick- 
ness which  for  a  considerable  distance  was  fully  6  feet.  They  run  farther 
north  and  south — how  much  farther  can  not  be  said.  They  appear  with 
undiminished  thickness  in  the  northern  exposure  and  may  be  seen  in  the 
Central  Railroad  cut  on  the  south.  They  crop  out  in  a  slope  produced  by 
later  erosion,  and  the  position  of  these  sand  strata  between  layers  of  till 
seems  to  me  to  have  in  part  determined  the  position  of  the  Lincoln  avenue 
plain  from  the  Northampton  road  to  the  Agricultural  College  and  north- 
ward. Vertically  one  can  see  in  every  section  how  the  sand  has  been 
scalped  by  the  ice,  and  when  one  considers  how  exceptional  a  grouping 
of  favorable  circumstances  must  have  been  required  to  shield  these  inco- 
herent and  exposed  sand  beds  beneath  the  ice  and  retain  any  portion  of 
them  intact,  one  will,  I  think,  be  inclined  to  consider  what  remains  as  but 
a  feeble  remnant  of  the  beds  as  originally  deposited.  Again,  the  texture 
of  the  beds,  the  large  scale  of  the  cross-bedding,  the  flow-and-plunge 
structure,  and  the  close  resemblance  to  the  flood  deposits  of  the  valley  in 
later  times,  make  it  probable  that  they  were  of  similar  origin,  the  one 
being  deposited  in  the  flood  waters  subsequent  to  the  first  retreat  of  the 
glacier,  while  the  other  and  later  beds  were  laid  down  by  the  floods  which 
accompanied  the  final  melting  of  the  ice. 

The  sands  then  furnish  strong  evidence,  if  not  conclusive  proof,  of  an 
interruption  in  the  continuity  of  the  presence  of  the  ice  in  the  valley  and  of 


INTEEGLAGIAL  SANDS.  555 

its  retreat  fnun  the  seaboiinl  to  a  point  north  of  Amherst,  while  the  abun- 
dant infoi-niation  conceniiug  the  character  of  the  glacial  deposits  in  Maine 
and  New  Hampshire,  ])ublished  by  Prof.  C.  H.  Hitchcock,  incline  me  to 
the  opinion  that  the  recession  continued  at  least  to  the  foot  of  the  White 
Mountains. 

The  middle  layer  of  the  till  (3)  in  the  cellar  section  is  a  compact,  stony 
clay,  showing"  no  distinction  in  color,  compactness,  or  texture  froin  either  the 
upper  or  the  lower  layer  when  exposed  in  fresh  section.  When  frozen  it 
showed  itself  a  little  more  sandy  toward  the  north  end  of  the  section,  evi- 
dently because  it  had  borrowed  part  of  its  material  from  the  sands  upon 
which  it  rests.  Its  sharp  horizontal  line  of  demarcation  from  the  sands 
below  I  have  already  described.  Its  upper  surface  is,  on  the  contrary, 
most  irregular.  It  sends  many  long,  tortuous  projections  into  the  sands 
above,  which  are  bent  over  and  spun  oiit  southward  as  the  smoke  of  a 
chimney  is  by  strong  wind,  and  indicate  clearly  the  direction  of  the  motion 
of  the  ice.  This  structure  is  more  manifest  in  the  section  itself  than  it 
can  be  made  in  the  drawing,  and  recalls  the  "fluidal"  structure  of  many 
volcanic  rocks.  Oftentimes  filaments  of  the  di'ift  lie  wholly  inclosed  in  the 
sand,  strung  along  in  the  direction  and  in  the  prolongation  of  one  of  the 
pi'ojections,  from  which  they  have  manifestly  been  separated. 

The  upper  layer  of  sand  (4)  is  about  1  foot  thick,  and  is  somewhat 
finer  than  the  average  of  the  lower  stratum — about  one-fom-th  inch — but 
agrees  with  it  under  the  microscope  in  degree  of  rounding  of  the  grains. 
It  shows  nowhere  distinct  traces  of  its  former  texture,  this  having  apparently 
been  wholly  replaced  by  a  fine  horizontal  lamination,  which  seems  to  me 
rather  a  pressure  cleavage  superinduced  by  the  weight  of  the  ice  upon  the 
mass  when  frozen,  while  below  it  is  confusedly  interwoven  with  the  till  on 
which  it  rests.  Above  it  joins  the  third  layer  of  till  along  a  line  nearly 
horizontal,  although  the  sand  and  the  till  are  thoroughly  molded  together. 
This  is  a  second  horizontal  fault.  Toward  the  north  end  of  the  section  it 
ends  abruptly,  being  cut  off  at  right  angles  to  its  length,  and  the  layers 
of  till  above  and  below  it  come  together,  separated  only  by  a  thin  seam  of 
sand,  which  in  places  disappears  entirely. 

Distinct  traces  of  a  second  stratum  of  sand  were  to  be  seen  in  some  of 
the  other  sections  I  have  described,  and  while  the  sand  and  second  till 
were  often  so  confusedly  interwoven  that  all  indications  of  a  second  sand 


556       GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

bed  might  well  have  been  obliterated,  I  am  inclined  to  think  that  such  a 
second  layer  was  deposited  on  a  second  till.  At  the  same  time  I  explain 
this  second  layer  in  the  cellar  section  as  a  sheet  of  sand  which  originally 
formed  a  part  of  the  lower  stratum  (2),  and  which,  when  frozen,  was  moved 
as  an  immense  bowlder  into  its  present  position.  Thus  it  would  be  classed 
with  the  true  sand  bowlders — regular  flattened  elipsoidal  sand  pockets  with 
their  longer  and  shorter  diameters  averaging  about  8  and  4  inches,  respec- 
tively, which  occur  not  rarely  in  both  the  upper  layers  of  the  till,  and 
which  can  be  explained  only  by  supposing  them  rounded  to  their  present 
form  when  compactly  frozen. 

Another  curious  phenomenon  which  points  in  the  same  direction  was 
observed  near  the  south  end  of  the  west  wall  of  the  cellar.  A  fissure  had 
opened  an  inch  and  a  half,  commencing  at  the  upper  surface  of  the  sand 
layer  and  running  down  through  the  middle  drift  layer  and  for  a  little  way 
into  the  lower  sand  stratum,  and  this  fissure  had  been  filled  with  alternating 
layers  of  clay  and  sand,  about  seven  in  all,  which  correspond  on  each  side 
of  the  center  and  present  a  curious  imitation  of  a  mineral  vein.  (See  figs. 
4,  5  of  PI.  XII.)  This  would  seem  also  to  find  its  explanation  most  natu- 
rally in  the  assumption  that  the  sand  layers  (2  and  4)  were  frozen  when  the 
fissure  was  formed  and  that  the  latter  was  kept  open  so  long  that  successive 
lavers  of  muddy  water  trickled  down  tlu-ough  it.  The  sand  bed  abounds  in 
small  masses,  1  to  2™"  in  size,  formed  of  a  few  grains  of  sand  cemented  with 
limonite. 

The  upper  layer  of  the  till  (5)  differs  in  no  respect  from  the  lower,  and, 
'like  it,  was  removed  with  chisels  and  heavy  sledges.  It  had  a  thickness  of 
5  feet  in  the  section,  but  the  ground  had  been  lowered  here  by  the  same 
amount,  so  its  whole  thickness  was  more  than  10  feet  as  it  appears  a  few 
feet  west  of  the  cellar.  The  massive  and  compact  character  of  the  stratum 
was  shown  by  the  effect  upon  it  of  the  extreme  cold  of  the  winter  of  1879. 
The  mass  above  the  sand  expanded  with  the  freezing  so  energetically  that 
it  projected  like  a  cornice  10  inches  in  the  west  wall  of  the  cellar,  which 
had  been  cut  away  vertically. 

I  am  thus  inclined  to  explain  the  phenomena  I  have  described  by 

assuming  that  after  the  deposition  of  the  first  till  there  was  a  retreat  of  the 

ice,  during  which  heavy  sand  beds  were  deposited  in  the  valley,  followed 

•  by  a  second  advance  of  the  ice,  which  then  plowed  up  and  destroyed  the 


INTERGLACIAL  SANDS.  557 

greater  portion  of  these  beds,  even  luoviug-  iuid  partially  molding  into  the 
till  beneath  it  great  sheets  of  the  sand,  as  in  the  case  of  the  bed  (4)  just 
described,  more  commonly  destroying  its  identity  entirely.  Nevertheless, 
I  think  one  would  be  strongly  inclined,  from  a  study  of  the  cellar  section 
alone,  to  assume  a  second  retreat  of  the  ice  for  the  formation  of  the  second 
sand  bed,  and  a  third  and  final  advance,  during  which  the  third  layer  of  the 
till  was  deposited. 

Or,  finally,  one  has  an  alternative ;  namely,  to  explain  all  these  sand 
beds  intercalated  in  the  till  as  deposited  by  subglacial  streams  during 
the  progress  of  a  single  glaciation  of  the  country.  The  fact  of  a  retreat 
and  second  advance  of  the  ice  seems  abundantly  proved  for  western 
Em-ope,  and  many  observations  in  this  country  point  in  the  same  direction, 
especially  those  made  toward  the  borders  of  the  ice  sheet,  since  traces  of 
a  double  glaciation  would  naturally  be  more  abundantly  preserved  there 
than  farther  north,  whence  the  ice  a  second  time  occupied  the  country  in 
such  force  as  to  obhterate  most  traces  of  the  incoherent  deposits  made 
in  the  interim.  Again,  the  compact,  unsorted,  and  clayey  character  of  the 
till  above  and  below  the  sands  shows  that  for  the  most  part  there  was  here 
no  free  ckculation  of  the  waters  below  the  ice,  and  we  should  expect  the 
waters  to  have  escaped  along  the  bottom  of  the  valley  and  not  along  its  side 
300  feet  above  the  bottom.  On  the  other  hand,  the  sand  beds  occupy  just 
the  same  position  fringing  the  valley  and  have  just  the  same  structure  as 
the  flood  beds  which  attended  the  final  disappearance  of  the  ice,  and  seem 
to  me  to  bear  the  same  relation  to  the  retreating  ice  of  the  earlier  epoch.  ^ 

In  1881  the  deep  railroad  cutting  south  of  College  Hill  exposed  the 
same  sand  beds  at  a  distance  of  1,463  feet  south  of  the  first  locality  cited 
above  on  the  Northampton  road,  displaying  the  following  section: 
Section  in  railroad  cutting  south  of  College  Hill. 

I        II  III 

Stratified  gravel 0  0to6  6 

Laminated  clays 6  ^ 

Gravel 3  4 

Till,  olive-green  to  brown *5  6to8  0 

Sand - lto3  4 

Till,  blue 1  to3  4 

Sand 3  6 

Till,  blue;  bottom  not  exposed. 

1 1  prefer  to  leave  this  section  as  it  was  written  in  1879,  although  now  the  case  in  favor  of  a 
second  Glacial  epoch  seems  to  me  less  strong  than  then. 


558  GEOLOGY  OP  OLD  HAMPSHIRE  COUNTY  MASS. 

The  lower  sand  bed  maintained  a  constant  thickness  for  450  feet  east 
and  west,  going  below  the  surface  at  the  east  end  of  its  exposure  and  dis- 
appearing at  the  end  of  the  cutting  (opposite  the  northeast  corner  of  Col- 
lege Grove)  with  the  same  thickness.  It  agreed  in  all  particulars  with  the 
lower  sand  in  the  cellar  section  above. 

The  upper  layer  of  sand  was  exposed  for  325  feet  east  and  west, 
measured  back  from  the  end  of  the  cutting.  It  is  greatly  contorted  and 
twisted  in  every  conceivable  way  into  the  upper  layer  of  till,  and  in  one 
place  it  is  wholly  interrupted  for  65  feet  and  appears  in  long  patches  and 
filaments  of  sand,  one  above  the  other,  in  the  mass  of  the  upper  layer  of  till. 

At  one  place  also  a  third  layer  of  sand  is  intercalated  in  the  mass  of 
the  till  halfway  between  the  two  more  extended  layers  of  sand,  with  a  thick- 
ness of  3  J  feet  and  a  length  of  80  feet,  and  ending  abruptly.  This  seems 
also  to  have  been  a  great  slab  of  frozen  sand  from  the  lower  bed,  while  the 
extent  of  the  upper  bed  here  makes  it  possible  that  there  were  two  inde- 
pendent sand  beds  deposited,  which  it  did  not  seem  necessary  to  assume 
from  the  former  sections. 

THE    UPPER    TILL. 

I  have  called  the  stratum  below  the  interglacial  sands  the  first  till,  as 
the  product  of  the  first  glaciation,  and  that  above  the  second  till,  it  having 
been  formed  during  the  second  advance  of  the  ice,  reserving  the  name  upper 
till  for  a  deposit  to  which  Prof.  C.  H.  Hitchcock  has  called  special  attention 
and  to  which  he  has  given  this  name.  It  is  conceived  by  him  to  have  been 
derived  from  the  material  taken  up  into  the  mass  of  the  ice  itself,  and  to  have 
sunk  down,  when  the  ice  melted,  in  a  coarse,  uncompacted,  and  unstratified 
sheet  upon  the  lower  till,  which  had  been  compacted  beneath  the  ice. 
While  the  lower  till  is  compact,  with  few  small  bowlders,  well  scratched  and 
not  far-traveled,  and  is  bluish  in  color,  having  been  protected  from  the  air  by 
the  thick  ice,  the  upper  till  is  loose,  contains  many  large  bowlders,  angular 
and  far-traveled,  and  is  reddish  from  oxidation.  I  have  been  able  to  recog- 
nize this  distinction  only  partially  in  the  valley.  The  immediate  deposi- 
tion of  the  Champlain  clays  upon  the  surface  of  the  lower  till  proper  at 
several  places  in  the  valley  shows  that  the  upper  till  was  not  uniformly 
spread  upon  the  latter,  and  where,  as  along  the  northern  part  of  High  street 
in  Amherst,  an  upper  loose  bufi"  layer  from  1  to  6  feet  thick  covers  the  blue 
compact  till,  I  do  not  find  the  bowlders  to  be  more  angular  or  far-traveled 
than  below,  and  am  inclined  to  explain  the  peculiarities  of  the  surface  layer 


BOWLDERS.  559 

as  due  to  the  surface  oxidation  and  disintegTation  by  frost.  The  same  was 
true  at  the  Central  Raih-oad  cutting  south  of  the  college,  where  beneath  the 
clays  the  till  was  in  its  upper  part  olive-green  to  brown,  and  blue -green 
below,  but  with  no  further  distinction  in  matter  of  compactness,  coarseness, 
or  derivation  of  bowlders.  I  have  seen  several  cases  where  the  up^^er  layer 
was  blue  and  the  lower  reddish. 

REMARKABLE    BOWLDERS. 

President  Hitchcock  has  described^  and  named  six  of  the  most  notable 
traveled  bowlders  to  be  found  on  the  east  of  the  river  in  the  valley  and  on 
its  border,  remarking  that  bowlders  of  the  largest  size  do  not  occur  in  this 
vicinity.     Those  named  are: 

THE   NORTHERNEK. 

An  irregular  mass  of  the  coarse  conglomerate  of  Metawampe  ( Mount  Tom), 
weighing  nearly  100  tons,  *  *  *  lodged  on  the  gneiss  rock  of  Pelham  Hill  in 
the  bed  of  a  large  brook  close  by  a  small  cascade,  where  it  was  pointed  out  to  me 
by  Mr.  Newall. 

ROCK   OREB. 

Near  the  top  of  Mount  Warner,  a  little  east  of  the  summit  and  in  the  cleared 
pasture,  lies  a  large  bowlder  of  imperfectly  prismatic  trap  or  greenstone.  Its  weight 
we  estimated  at  78  tons.  The  rock  of  the  mountain  is  granite  and  mica-schist,  and 
no  trap  in  place  is  found  to  the  north  till  we  reach  the  north  part  of  Sunderland 
and  the  south  part  of  Deerfield,  say  some  10  miles  distant.  From  that  range  this 
bowlder  undoubtedly  came.    *     *     * 

ROCK  ETAM. 

Northwest  of  Rock  Oreb,  say  a  quarter  of  a  mile  in  the  woods,  and  far  down  the 
northwest  slope  of  the  mountain,  is  another  and  larger  bowlder  of  the  same  variety  of 
trap.    We  estimated  the  weight  of  the  Hadley  Btam  to  be  385  tons.    *     *     * 

Another  bowlder  of  the  same  columnar  trap  projects  from  the  ground  on  a  lower 
bench  of  the  mountain  southeast  of  Eock  Oreb.  Its  exposed  portion  is  half  as  large 
as  the  latter. 

THE   MAGNET. 

At  the  western  foot  of  the  steep  part  of  Holyoke,  and  a  little  south  of  the  place 
where  the  railroad  goes  up  the  hill,  lies  a  large  bowlder  of  trap  precisely  like  those 
just  described  on  Mount  Warner.  It  is  15  feet  high,  and,  by  a  loose  estimate,  I 
think  it  must  weigh  300  tons.  It  is  remarkable  for  exhibiting  on  its  north  face  a 
vast  number  of  magnetic  poles  sufficiently  strong  to  completely  invert  a  common 
magnetic  needle,  forming  in  fact  several  continuous  lines  of  poles.  I  spent  some 
days  several  years  ago  in  tracing  them  out.  These  facts  furnish  a  reason  for  the 
name  which  I  venture  to  propose  for  it,  viz.  The  Magnet.     I  formerly  supposed  that 

'Reminiscences  of  Amherst  College,  pp.  264-265. 


560        GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

it  had  been  broken  off  from  the  trap  ledges  immediately  above  it,  but  its  exact 
correspondence  with  Oreb  and  Etam  in  characters,  and  want  of  resemblance  to 
the  trap  of  Holyoke,  make  it  more  probable  that  it  was  brought  into  its  present 
position  by  drift  agency  and  originated  in  the  same  region  as  those  on  Warner. 

THE    SENTINEL. 

As  we  ascend  Mount  Boreas,  looking  northerly  up  the  valley  on  its  east  side, 
*  *  *  we  see  a  prominent  bowlder  lying  near  the  base.  We  find  it  to  be  com- 
posed of  gneiss  and  lying  on  gneiss,  although  the  stratification  on  both  is  very 
indistinct.  It  weighs  something  less  perhaps  than  200  tons,  although  not  accurately 
measured. 

THE   KOCKING   STONE. 

Some  years  ago  a  bowlder  of  several  tons  weight,  capable  of  being  rocked  a  little 
by  one  man,  lay  on  a  farm  then  owned  by  Mr.  Grout,  about  a  mile  north  of  Pelham 
Center,  on  the  road  to  Shutesbury. 

OTHER   BOWLDERS. 

The  finest  bowlder  ever  found  in  the  valley  is  the  one  now  lying"  in 
front  of  the  Woods  cabinet,  where  it  was  bi'ought  by  the  class  of  1857,  as 
the  inscription  npon  it  indicates.  Its  former  north  end  now  faces  south. 
(See  PI.  XXXIII.)  It  was  uncovered  in  lowering  the  road  in  front  of  the 
residence  of  the  late  Edward  Dickinson,  and,  judging  frona  the  excavations 
here  for  the  waterworks,  it  was  derived  from  the  lower  till.  It  is  a  large, 
coarse,  red  sandstone,  in  size  78  by  66  by  33  inches,  the  four  sides  planed 
down  to  a  flat  convex  surface  and  striated  longitudinally,  the  ends  for  the 
most  part  still  rough  and  irregular.  It  exhibits  exactly,  on  a  large  scale, 
the  form  of  the  most  perfectly  polished  glacial  stones.  The  striae  of  the 
upper  surface  when  it  was  first  exposed  ran  north-south,  as  do  the  striae  in 
the  valley,  and  it  may  be  that  the  ice  passed  over  it  after  it  was  fixed  in 
the  till,  thus  polishing  its  fourth  side,  which  was  naturally  at  first  mistaken 
for  a  ledge.     A  full  description  of  it  was  published  by  President  Hitchcock.-^ 

The  largest  specimen  of  the  buff  quartzite,  which  is  so  abundant  in 
smaller  masses  throughout  the  valley,  is  the  one  mentioned  on  page  542, 
in  the  yard  of  the  Whitney  homestead,  on  King  street,  in  Northampton, 
which  came  from  the  Denniston  place,  near  Florence.  This  quartzite,  I 
think,  came  into  the  valley  farther  north  from  Vermont  and  then  drifted 
down  in  the  valley  with  the  altered  direction  of  the  ice. 

'Am.  Jour.  Sci.,  2cl  series,  Vol.  XXII,  1857,  p.  397. 


BOWLDERS.  561 

A  siujilc  l)()\vl<lcr  of  compact,  pure  magnetite,  about  a  foot  in  diam- 
eter, was  Ibuiid  1)}'  Mr.  W.  Newall,  of  Pelliam,  in  the  brook  above  the  Orient 
House.  A  portion  of  it  is  pi-eserved'in  the  collection  of  bowlders  in  the 
Amherst  College  cabinet.     It  came  probably  from  Bernardston. 

The  liowlders  of  green  hornblendic  quartzite  which  have  furnished  so 
many  mineral  specimens  under  the  name  of  Shay's  flint,  praze,  hornstone 
etc.,  the  origin  of  which  was  unknown,  I  have  traced  to  a  band  of  tonalite, 
from  which  this  rock  has  been  formed  as  an  aphanitic  and  siliceous  product, 
by  crushing  along  the  great  eastern  fault.  It  appears  capping  the  Pelham 
gneiss  in  a  thin  band  along  its  western  exposure  in  Pelham,  and  is  now 
mostly  concealed  by  drift.  It  is  best  exposed  in  the  bluff's  50  rods  west  of 
the  road  running  south  from  the  house  of  Mr.  S.  Jewett,  in  the  west  part 
of  Pelham,  where  this  road  crosses  the  town  line. 

Just  at  the  w^est  border  of  the  village  of  Amherst,  on  the  brow  of  the 
hill  and  along  a  north-south  line,  the  large  conglomerate  bowlders  were 
accumulated  in  unusual  abundance.  As  the  land  has  been  long  under  cul- 
tivation, many  have  been  removed,  but  many  still  project  from  the  surface. 
In  building  my  house,  on  Northampton  road,  I  had  to  remove  three,  which 
contained  about  300  cubic  feet.  It  may  be  assumed  with  great  probabihty 
that  they  came  from  the  rock-cut  benches  on  the  west  of  Mount  Toby. 

President  Hitchcock  notes ^  "about  1  mile  northeast  of  the  college, 
in  a  field,  numerous  bowlders  of  chalcedony  and  hornstone,  resembling 
almost  exactly  a  great  vein  in  the  southeast  part  of  Conway,"  with  which 
much  pyrolusite  is  associated.  These  bowlders  continue  to  be  found,  and 
one  of  my  former  students,  Mr.  Horace  B.  Patton,  found  a  great  mass  of 
the  same  rock,  about  6  feet  on  a  side,  on  the  eastern  spur  of  Mount  Holyoke. 
I  have  little  doubt  they  all  came  from  Conway. 

Perched  bowlders,  often  poised  so  that  they  can  be  easily  moved, 
occur  in  several  places  in  the  region.  Such  a  one  is  the  "Hang-inff  Rock," 
on  the  farm  of  Jonathan  Buddington,  in  Leyden,  which  is  estimated  to 
weigh  20  tons,  and  has  been  known  since  1800.  It  can  be  moved  with 
one  hand.  On  the  old  Atwood  farm  near  the  Winchester  line,  in  Warwick, 
is  another,  estimated  weight  100  tons,  which  can  also  be  moved  with  one 
hand;  also  two  specimens  on  the  Blackmer  farm,  in  Greenwich.  The  above 
three  are  noted  in  History  of  Connecticut  Valley,  Vol.  II,  page  754. 

'  Geology  of  Massachusetts,  1835,  p.  344. 
MON  XXIX 36 


CHAPTEE    XVII. 
THE   CHAMPLAIN    PERIOD. 

GLACIAL  LAKES  EAST   OF  THE   CONNECTICUT  RIVER. 

INTRODUCTION. 

It  is  very  remarkable  that  while  the  heavy  sand  and  gravel  dejDOsits 
of  a  complex  series  of  glacial  rivers  and  lakes  extend  over  the  whole  eastern 
half  of  the  three  counties  east  of  the  Connecticut  River,  such  deposits  are 
almost  wholly  wanting  on  the.  western  side.  Amherst,  in  the  middle  of  the 
area,  is  about  80  miles  from  the  sea  and  the  same  distance  from  the  Sound, 
and  it  has  come  to  be  very  plain  to  me  that  the  ice  front  during  the  retreat 
of  the  inland  ice  was,  over  this  territory,  a  northeast-southwest  line;  not  a 
straight  line,  but  one  projecting  south  in  a  loop  in  the  broad  Connecticut 
Valley.  The  effect  of  this  would  be  that  the  country  to  the  east  would  be 
set  free  on  any  given  parallel  earlier  than  that  on  the  west,  and  that  in  the 
east  the  headwaters  and  gradually  nearly  the  whole  of  the  drainage  area 
of  each  tributary  would  be  set  free  before  the  southward-projecting  tongue 
of  ice  in  the  main  valley  would  permit  its  unobstructed  passage  to  join  the 
waters  of  the  Connecticut;  while  on  the  western  side  the  ice  melted  back 
up  the  streams  to  their  heads,  leaving  their  lower  portions  first  and  using 
their  channels  for  the  passage  of  their  abundant  waters,  and  thus  delivering 
through  them  to  the  main  valley  an  abundant  siipply  of  "gletchermilch" 
(the  fine  silt  from  beneath  the  glacier),  but,  except  in  a  few  cases  where  a 
nortli-south  side  valley  sloped  northward,  leaving  the  valleys  open  and  not 
clogged  by  the  great  accumulations  of  sand  found  so  commonly  on  the 
eastern  side. 

From  this  it  follows  that  our  history  of  the  stratified  deposits  which 
accompanied  the  melting  of  the  ice  must  begin  at  the  southeast  of  the  region 
and  proceed  northwesterly,  ending  in  the  northwest,  and  we  shall  find  a 
gradual  change  in  this  direction  and  a  remarkable  difference  on  the  two 
sides  of  the  river. 

562 


THE  OUAMPLAIN  PERIOD.  563 

Wf  liavo  first  to  discuss  lakes  at  elevations  of  800  to  1,000  feet  above 
sea,  held  back  in  basins  on  the  eastern  border  of  the  region,  high  up  on  the 
western  slope  of  the  great  plateau  of  central  Massachusetts,  which  were  set 
free  by  the  first  melting  of  the  ice  over  the  area.     We  must  then  study- 
how  the  continued  retreat  of  the  ice  uncovei'ed  gradually  a  more  and  more 
complex  network  of  longitudinal  and  transverse  valleys  in  which  successive 
series  of  lakes  and  rivers  found  temporary  place  and  were  di-ained  over 
passes  now  abandoned,  as  these  passes  were  one  after  the  other,  and  at 
lower  and  lower  levels,  opened  by  the  ice.     We  shall  see  how  this  melting 
process  went  on  until  at  last  the  space  between  the  eastern  rocky  border 
slope  of  the  main  valley  and  the  tongue  of  ice  still  extending  southward 
in  the  valley  from  the  main  mass  became  a  channel  by  which  for  a  time 
the  waters  escaped  into  the  open  valley  below,  and  in  which  they  lodged 
a  great  mass  of  coarse,  tumiiltuously  irregular,  kame-like  sands.     These 
sands  were  afterwards  in  greater  or  less  measure  planed  down  to  the  level 
of  the  high  terrace  formed  by  the  flood  waters  which  occupied  the  Con- 
necticut Valley,  and  as  they  often  covered  masses  of  the  retreating  ice,  are 
now  deeply  pitted  here  and  there  at  the  surface  by  kettle-holes,  or  have 
sunk  down  into  a  system  of  reticulate  ridges,  due  to  the  melting  of  the  ice. 
While  the  bottom  of  the  valley  on  a  given  latitude  was  still  covered 
by  the  ice  and  kept  free  from  the  deposits  of  the  melting,  it  is  everywhere 
indicated,  for  the  central  portion  of  the  valley  at  least,  that  the  tongue  of 
ice  was  thrust  at  its  southern  end  into  deep  water,  buoyed  up  and  floated 
off,  and  was  immediately  succeeded  by  the  laminated  clays.     All   along 
the  western  border  a  complex  and  interesting  series  of  beds  show  clearly 
the  alternate  advance  and  retreat  of  the  ice,  at  least  three  times  repeated, 
and  the  high  terrace  on  this  side  is  comparatively  narrow,  and  in  many 
places  remote  from  the  mouths  of  streams  is  represented  only  by  a  narrow 
shelf  in  the  rock  or  by  a  notch  in  the  heavy  deposits  of  till.     The  high 
teiTace  is  not,  as  is  often  the  case  on  the  eastern  side,  represented  by  a 
broad  area  of  kame-like  sand  which  is  planed  down  to  its  level,  but  is  of 
earlier  date  of  deposition  than  the  time  of  the  highest  level  of  the  flooded 
Connecticut.     On  both  sides  the  high  terrace  or  bench  which  marks  the 
highest  stage  of  the  Connecticut  lakes  may  be  defined  as  a  series  of  deltas, 
but  those  on  the  west  are  proportionately  much  less  extended  and  of  finer 
material  than  those  on  the  east.     Moreover,  in  the  northwest  corner  of  the 


564  GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

basin,  in  Grreenfield,  the  ice  was  thrust  into  the  valley  and  lingered  there 
until  the  period  of  flooding  had  passed  its  climax  and  the  waters  had  begun 
to  recede. 

Finally,  from  the  shoreward  (western)  edge  of  the  high  sand  terrace 
on  the  western  side  one  passes  immediately  onto  the  bare  ledges  of  rock 
or  onto  the  coarse  till  of  the  uplands,  and  not,  as  one  often  may  on  the 
east  side,  onto  sands  which  stretch  continuously  many  hundred  feet  above 
the  level  of  the  former  Connecticut  Lake.  Only  in  exceptional  cases,  as 
noted  above,  where  a  valley  dips  northward,  has  the  ice  clogged  its  mouth 
and  aided  in  the  accumulation  of  glacial  lake  deposits  on  this  side  also. 
These  are  here  of  limited  extent  and  importance. 

On  the  east  side  of  the  great  longitudinal  valley  of  the  Connecticut 
the  land  rises  rapidly  to  a  height  of  8G0  or  900  feet  and  then  slowly 
merges  into  the  plateau  of  Worcester  County.  It  is  a  hilly  country,  and  as 
the  rocks  strike  north  and  south,  it  is  cut  into  a  series  of  parallel  ranges  by 
north-south  valleys;  only  two  transverse  valleys,  occupied  by  the  Chicopee 
and  Millers  rivers,  cut  back  beyond  the  front  range  of  hills.  The  tribu- 
taries of  both  these  extend  back  far  beyond  the  limits  of  the  county  and 
branch  out  over  the  Avestern  half  of  the  Worcester  County  highland. 
From  the  southern  line  to  the  middle  of  the  State,  in  the  latitude  of 
Amherst,  the  front  range  is  broken  only  by  the  long  gorge  of  the  Chicopee. 

Pelham  Brook  in  Amherst  and  Locks  Pond  Brook  in  Montague  break 
through  the  front  range,  but  no  other  stream  does  this  except  Millers  River, 
already  mentioned,  before  we  reach  the  north  line  of  the  State.  Just  over 
this  line  Perchee  Brook  sets  back  through  the  front  range  and  drains  the 
broad  valley  east  of  it  in  Warwick. 

The  order  of  the  formation  of  these  lakes  must  have  been  from  south- 
east to  northwest,  as  already  stated,  and  we  have  thus  to  discuss  the  deposits 
found  in  the  southeast  portion  of  the  area  first,  and  then  proceed  north  and 
west.  Where  the  Chicopee  River  extends  eastward  beyond  the  limits  of 
the  county  the  longitudinal  valleys  are  less  pronounced,  the  whole  area  is 
elevated  and  flat,  and  the  conditions  were  less  favorable  for  the  formation 
of  glacial  lakes,  and  for  some  distance  eastward  no  trace  of  them  is  to  be 
found,  so  far  as  I  have  seen.  It  is  a  broad,  high  area  of  undisturbed  till, 
not  covered  by  any  later  deposit.  Farther  east  distinct  and  extensive  kame 
ridges  run  north  and  south  across  the  area  and  seem  to  replace  the  lake 
sands  discussed  below. 


THE  BRIMFIELD  LAKE.  565 

As  tlio  it'o  melted  back  across  Worcester  County  the  water  ran  off 
across  it  into  more  eastern  th-ainage  systems  and  lias  left  its  esker  ridges 
behiinl  ir  to  mark  tlie  place  of  the  ice  streams,  but  as  the  ground  began  to 
slope  toward  the  Connecticut  and  became  grooved  by  deep  valleys,  at  once 
the  retreat  of  the  ice  became  more  irregular  and  the  escape  of  the  water 
more  interriijited. 

ICE    BARRIERS. 

Upon  the  map  the  position  of  the  ice  barriers  which  completed  the 
shore  line  of  glacial  lakes  and  watercourses  is  marked  by  a  series  of  red 
circles.  This  jjosition  is,  in  the  nature  of  the  case,  only  an  approximate  one, 
often  an  average  of  many  shifting  positions.  At  times  a  later  erosion  has 
removed  the  beds  left  at  the  line  of  contact,  and  a  series  of  later  terraces 
occupies  its  place.  In  this  case  it  seemed  in  several  instances  necessary  for 
the  clearness  of  the  map  to  represent  as  closely  as  possible  the  fact  and  the 
approximate  position  of  the  ice  boundary,  and  since  to  represent  it  in  its 
true  position  would  confuse  the  expression  of  these  later  terraces  with  which 
it  had  no  relation,  it  was  found  necessary  to  draw  this  boundary  upon  the 
color  representing  the  lake  area  and  along  that  edge  of  the  area  nearest  to 
its  true  position.  Whenever  possible  it  is  drawn  just  outside  this  area 
across  the  till.  On  the  map  these  ice  barriers  are  numbered  from  southeast 
across  the  State  to  northwest  No.  1  is  applied  to  the  oldest  series  of  bar- 
riers, approximately  contemporaneous  and  representing  portions  of  a  single 
ice  front  which  retained  the  Brimfield  lakes  and  tiirned  their  drainage  awav 
east  of  the  Monson  Valley  and  across  Brimfield  and  Wales;  No.  2  is  apphed 
to  the  next  clearly  recognizable  series,  which  diverted  the  waters  into  the 
Monson  Valley ;  and  so  with  the  others.  The  evidence  upon  which  these 
barriers  have  been  located  is  given  in  detail  in  the  description  of  the 
separate  basins.  Arrows  are  also  used  on  the  map  to  indicate  the  direction 
of  flow  of  the  waters,  and  especially  the  passes  by  which  the  lakes  were 
drained. 

THE    BRIMFIELD    LAKE. 

This,  the  oldest  and  highest  of  the  lakes,  occurs  on  the  eastei-n  border  of 
Hampden  County,  in  the  northwest  corner  of  Brimfield,  at  a  height  of  830 
feet  above  sea  (PI.  XXXV,  D,  1  b).  It  is  a  square  basin,  the  north  and 
south  sides  of  which  are  rock;  on  the  east  the  waters  bathed  an  enormous 
"felsenmeer"  of  great  bowlders  of  gneiss,  a  rock  which  always  furnishes  the 


566  GEOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 

most  abundant  and  the  largest  woolsack-like  bowlders;  on  the  west  its  heavy- 
sands  and  clays  overhang  the  valley  of  the  Quaboag  (as  the  Chicopee  River 
is  called  above  Palmer)  and  the  station  of  Brimfield,  which  is  390  feet 
above  the  sea.  When  it  was  formed  the  ice  must  have  occupied  the  whole 
of  Hampden  County  west  of  this  point,  and  must  have  filled  the  valley  of 
the  Quaboag,  here  running  north  and  south,  to  furnish  the  western  wall  of 
'the  basin.  One  standing  at  the  railroad  station  and  looking  east  can  see 
that  the  horizon,  almost  over  one's  head,  is  the  horizontal  line  of  the  front 
of  the  high,  level  sands  of  this  lake,  which  extend  north  and  south  for 
nearly  2  miles  and  stretch  back  east  for  a  mile  and  a  quarter.  Just  in 
front  of  the  station,  at  a  large  brickyard,  a  fresh  vertical  section  of  20  feet 
of  horizontal,  perfectly  sorted  yellow  sand  is  exposed. 

In  many  places  a  vast  number  of  the  great  bowlders  of  porphyritic 
gneiss  have  been  dropped  into  the  sand  from  icebergs  which  separated 
from  the  ice  front  and  floated  on  the  lake,  and  at  a  distance  many  slopes 
produced  by  erosion  look  like  the  coarsest  till.  They  have,  however, 
everywhere  the  contour  of  sand  slopes,  and  are  very  heavy  masses  of 
well-bedded  sand.     Beneath  these  sands  is  the  following  peculiar  section 

of  till: 

Section  of  clay  at  Brimfield  station. 

Feet. 

Till  with  great  bowlders  on  its  surface 6.5 

Brown  laminated  clay  with  few  bowlders 12 

Blue  laminated  clay  without  bowlders,  very  fine  and  tenacious ;  exposed .     6.5 

These  clays  seem  to  be  subglacial  deposits,  or  to  have  been  deep- 
water  deposits  overridden  by  a  readvance  of  the  ice.  The  section  was 
taken  at  the  kiln. 

South  of  this  lake  are  two  others  belonging  in  the  same  series,  which 
may  be  called  the  Parksville  and  the  East  Monson  lakes.  The  former  was 
half  filled  from  the  north  by  heavy  sands  thrust  forward  into  its  basin  as 
a  great  delta,  whose  front  scarp  is  still  well  preserved  as  a  steep  south  slope, 
crevassed  at  one  point  by  the  stream  that  emptied  the  lake  northwardly. 
Around  the  south  half  of  the  basin  its  shore  line  is  hardly  traceable. 

THE    MONSON    ESKER. 

It  was  perhaps  but  little  later  than  the  time  of  the  formation  of  Brim- 
field Lake,  while  the  ice  was  thrust  down  the  deep,  straight  valley  which 


THE  MONSON  DRAINAGE.  567 

opens  scMithwanlly  from  tlie  Quaboag  at  Palmer  and  runs  south  across 
Moiison  (occupieil  l)v  the  New  London  Northern  Kaih'oad)  as  far  as  South 
Monson,  that  the  waters,  confined  b}'  the  high  ground  whicli  borders  the 
valley,  ran  down  over  the  ice  and  formed  the  Monson  esker  (k).  Tliis  now 
stretclies  as  a  marked  ridge  south  from  a  point  west  of  the  second  bridge 
over  the  Monson  Brook  at  W.  Leach's,  crosses  the  brook  at  North  Monson, 
and  runs  down  its  east  side  to  Monson  village.  From  this  point  the  whole 
valle^',  grown  broader,  is  filled  with  an  enormous  accumulation  of  sands, 
mostly  finely  sorted  and  of  great  thickness,  at  times  containing  great  sheets 
of  coarse,  indeed  of  the  coarsest,  gravel,  all  of  well-rounded  pebbles  inter- 
calated in  the  most  irregular  and  indescribable  manner,  the  surface  being 
also  pitted  by  deep  kettle-holes.  These  sands  rise  to  a  height  of  660  to 
680  feet,  and  as  the  greatest  height  of  the  divide  at  the  State  line,  where 
the  valley  narrows  to  a  canyon  and  where  the  sources  of  the  Monson 
Brook  flowing  north  and  the  Willimansett  flowing  south  now  approach 
closely,  is  620  feet,  the  waters  must  have  passed  through  this  gorge  with 
great  depth  and  velocity. 

I  have  marked  an  ice  front  (b^,  PL  XXXV,  D)  across  the  deep  Monson 
Valley  at  a  point  where  at  its  sotith  end  the  esker  meets  the  high  gravels, 
which  here  expand  suddenly  to  fill  the  whole  valley,  as  this  represents  the 
point  where  the  esker-forming  stream  flowed  off"  from  or  out  from  under 
the  front  of  the  ice  lobe,  whose  irregiilar  advances  have  thrown  the  sand 
beds  into  so  great  confusion. 

THE  MONSON  DRAINAGE. 
THE  EASTERN   PALMEE   AND   MONSON  LAKE. 

In  order  to  understand  the  complex  series  of  transient  lakes  and  river 
courses  (1  m)  which  followed  upon  the  gradual  recession  of  the  ice  from  the 
point  where  it  held  back  the  waters  of  the  Brimfield  Lake,  we  must  study 
with  some  detail  the  configuration  of  the  region  about  the  jDoint  of  conflu- 
ence of  the  four  branches  of  the  Chicopee  River,  which  can  best  be  done 
with  the  large  topographic  map  on  the  mile  scale  (Palmer  sheet). 

The  Quaboag  (the  east  branch  of  the  Chicopee),  where  it  enters  the 
county,  leaves  its  transverse  valley  to  flow  south  along  the  east  side  of 
Palmer  in  a  deep  longitudinal  valley  to  the  southeast  corner  of  the  town 
at  Fentonville,  where  it  turns  west  again  in  a  transverse  valley.     Just 


568  GEOLOGY  OF  OLD  HAMPSHIEE  OOTJNTY,  MASS. 

before  reaching-  Palmer  \dllage  the  deep,  narrow  Monson  Valley  opens  oiit 
southwardly  from  this  Palmer  Valley  and  runs  south  across  the  town, 
bounded  by  continuous  high  ground.  This  Monson  Valley  becomes  a 
narrow  canyon,  which  is  at  the  State  hue  a  low  watershed  with  a  height  of 
620  feet  above  the  sea.  A  brook  gathering  here  runs  north  into  the  Qua- 
boag,  and  a  little  farther  south  are  the  sources  of  the  Willmansett,  which 
flows  south  into  the  Sound.  The  Quaboag  flows  west  past  Palmer,  and 
immediately  turns  north.  Its  valley  is  continued,  however,  at  a  higher 
level  (380  feet)  westward  to  the  Connecticut  basin,  and  is  now  occupied  by 
the  Boston  and  Albany  Railroad.  This  continuation  I  have  called  the  Elhs 
Mills  Valley.  The  Quaboag  turns  north  in  a  naiTOw  gorge  between  the 
hill  south  of  Three  Rivers  and  Mount  Dumpling,  and  soon  turns  west  to 
Three  Rivers.  On  the  north  of  Mount  Dumpling  the  Ware  River,  coming 
down  from  the  north,  bends  west  also  in  the  narrow  Thorndyke  gorge,  and 
joins  with  the  Swift  River  and  the  Quaboag  to  form  the  Chicopee  River  at 

Three  Rivers. 

The  present  gorge  of  the  Chicopee  River  west  of  Three  Rivers  is  the 
last  and  most  northern  outlet  of  the  waters  of  the  drainage  areas  of  these 
three  streams,  and  it  was  opened  only  after  the  ice  had  receded  from  the 
Belchertown  plateau  to  the  north.  The  Ellis  Mills  Valley  was  an  earlier 
outlet  at  a  higher  level,  and  the  Monson  Valley  was  a  still  earlier  outlet 
farther  southeast  and  at  a  still  higher  level.  This  latter  outlet  determined 
the  level  of  the  lake  here,  around  Palmer,  whose  waters  rose  to  the  height 
of  620  feet.  The  ice  then  occupied  the  Belchertown  plateau  and  the  Swift 
and  Ware  river  valleys  and  approached  Pattaquattic  Hill  on  the  north  and 
west,  and  the  ice  front  extended  south  past  Palmer  to  Chicopee  Mountain 
(b^  PI.  XXXV,  D). 

The  best  remnant  of  this  lake  is  seen  by  momrting  to  the  top  of  the 
o-reat  level  sand  plain  east  of  Palmer  Center  and  following  it  southeast  past 
Calkins  Pond  for  a  distance  of  nearly  3  miles.  It  has  well-marked  shore 
Hues  against  the  rocks  on  either  side,  is  nearly  a  mile  wide,  and  where, 
on  the  south,  it  overhangs  the  Quaboag  at  Blanchardsville  its  sands  are 
above  200  feet  thick  and  its  broad,  flat  surface  is  610  feet  above  sea  level. 
Approaching  Palmer,  its  sands  swing  round  the  rocky  spurs  which  have 
bounded  it  on  the  west,  on  the  east  extending  up  the  Quaboag  Valley,  and 
end  on  the  south  in  a  great  lunate  delta  scarp,  at  the  foot  of  which  the 
river  runs.     The  Monson  Valley  is  its  almost  direct  continuation  southward, 


THE  ELLIS  MILLS  DRAINAGE.  569 

ami  the  cliariU-ter  of  tlic  hottoni  of  this  Aalk'V,  witli  the  great  esker,  only 
halt'  covrrc'il,  windiiiii'  down  its  middle  at  a  much  lower  level,  shows  that 
the  valley  can  not  have  heen  tilled  to  the  620-foot  level  and  then  reexca- 
vated,  but  that  the  work  of  fillini)-  the  lake  was  arrested  at  this  point  by 
the  further  recession  of  the  ice  that  opened  at  a  lower  level  the  g'orge 
which  forms  the  continuation  of  the  Palmer  Valley  eastward,  and  which  I 
have  called  above  the  Ellis  ]\Iills  Valley.  During  the  continuation  of  this 
lake  its  waters  escaped  through  the  Monson  Valley  to  the  south  and  did 
nitt  quite  plane  the  sands  accumulated  there  down  to  the  level  of  the  pass 
across  the  whole  valley,  as  a  central  channel  cut  in  the  sands  passes  beyond 
the  headwaters  of  Monson  Brook  at  the  State  line  and  is  occupied  farther 
south,  beyond  the  divide,  by  the  headwaters  of  the  Willimantic. 

THE  ELLIS  MILLS  DRAINAGE. 
THE  PALMER  LAKE. 

As  the  ice  retreated  westward  a  next  important  halting  place  (b^, 
PL  XXXV,  D)  is  suggested  by  the  configuration  of  the  country  and  by 
heavy  moi-ainic  accumulations.  Here  the  ice  abutted  against  the  high  hills 
east  of  Bonds  -callage,  against  Hog  Hill,  surrounded  Mount  Dumpling,  and 
for  a  time  still  closed  the  passage  between  Mount  Dumpling  and  Bald  Peak. 
During  this  time  the  Ware  River  Valley  was  freed  from  ice  and  filled  with 
a  great  volume  of  sand,  and  the  beds  at  the  530-foot  level  (1  p  a),  extending 
north  from  Palmer  east  of  Thorndyke  and  Bonds  village,  were  laid  down, 
the  latter  by  waters  coming  from  the  lower  Swift  River  Valley. 

The  establishment  of  this  level  for  so  long  a  distance  may  mean  only 
that  the  time  did  not  suffice  to  fill  to  the  620-foot  level  the  area  newly  left 
by  the  ice,  and  that  the  drainage  was  still  south  across  Monson.  I  have 
assumed  that  the  outlet  was  south  across  Palmer  and  then  west,  by  the 
breaching  of  the  south  end  of  the  barrier  (b*),  and  around  the  north  foot 
of  Bald  Peak  into  the  Ellis  Mills  Valley,  perhaps  carried  along  the  north 
slope  of  Bald  Peak  and  held  up  to  530  feet  by  the  ice. 

THE   WARE   AND   SWIFT   RIVER   LAKES. 

It  seems  quite  plain,  however,  that  a 'more,  effective  washout  occui'red 
when  the  ice  barrier  (b*)  yielded  just  south  of  Mount  Dumpling  and  all 
the  waters  of  the  Ware  River  Valley  swept  west  of  Wapples  station  and  past 


570  GEOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 

Palmer  Center  and  then  along  south  of  Mount  Dumpling,  directly  into  the 
Ellis  Mills  Pass,  forming  the  deep  channel  cut  in  the  sands  along  this  line, 
which  is  in  places  worn  down  to  the  till.  This  channel  remains  practically 
intact  for  a  long  distance  north  and  south  of  Palmer  Center. 

With  the  melting  of  the  ice  back  to  b",  the  lower  reaches  of  the  Swift 
River  Valley  were  set  free,  the  Ware  River  passed  out  through  the 
gorge  at  Thorndyke  instead  of  by  way  of  Palmer  Center,  and  the  Ellis 
Mills  drainage  was  fully  established.  That  portion  of  b"  abutting-  on 
Mount  Dumpling  is  a  massive  moraine,  but  the  ice  front  seems  soon  to 
have  extended  more  nearly  north  and  south,  between  the  portion  repre- 
sented east  of  Bonds  village  and  the  part  south  of  Three  Rivers.  The  new 
level  thus  established  by  the  Ellis  Mills  Pass  of  390  to  400  feet  is  manifest 
in  terraces  (1  s)  rising  from  that  level  as  one  goes  east  up  the  Quaboag  or 
the  Monson  Brook.  The  bi'oad  sand.s  of  Ware  Valley  hardly  rise  above 
500  feet,  as  they  are  followed  northeast  far  beyond  the  limits  of  the  map, 
and  from  them  a  lobe  extends  northward  up  Beaver  Brook  and  past  its 
headwaters,  to  connect  with  the  broad  Orange-Enfield  sands. 

A  striking  proof  of  the  contention  on  page  569,  that  the  earlier  East 
Palmer-Monson  lake  beds .  did  not  fill  the  northern  half  of  the  Monson 
Valley  and  that  the  waters  were  at  this  later  time  held  up'to  the  400-foot 
level  in  the  empty  valley,  is  found  in  the  perfectly  formed  sand  spit  at  the 
400-foot  level  which  projects  westward  halfway  across  the  mouth  of  the 
Monson  Valley  just  south  of  Quaboag.  This  has  just  the  form  which 
would  result  from  the  passage  of  the  main  current  west  past  the  slack 
water  still  standing  in  the  Monson  Valley  to  the  south. 

The  Swift  River,  for  a  long  way  above  Bonds  village,  runs  now  in  a 
deep  and  narrow  valley  cut  in  the  till,  but  high  up  on  its  side  are  the  broad 
sands  rising  to  400  feet  which  belong  to  the  series  under  consideration. 
On  following  these  sands  eastward  to  the  point  where  the  Central  Railroad 
crosses  the  ice  barrier  (b^),  one  sees  that  they  sink  by  a  sudden  irregular 
slope  30  feet,  down  to  the  level  of  the  Belchertown  sands,  along  the  line 
where  they  .were  supported  by  the  ice  of  this  barrier.  These  sands  may 
be  traced  a  long  way  north,  following,  at  a  level  high  above  the  present 
stream,  the  West  Branch  of  the  Swift  River,  and  branching  with  the 
stream  at  Enfield  to  blend  with  the  extensive  Orange-Enfield  sands.  The 
main  stream  of  Swift  River  here  passes  through  a  remarkable  gorge  cut 


THE  WARE  AND  SWIFT  RIVER  LAKES.  571 

obliciurlv  iUTOSs  the   liig'li  rid-i'^'  that  separates  the  narrow  West  Branch 
Valley  (Hi  the  west  from  tlie  Ijroad  flat-bottomed  Orange-Enfield  basin  on 

the  east. 

The  effect  of  the  ice  front  as  it  rested  here  is  seen  clearly  in  the 
tillinii-  I  if  the  Beaver  Brook  channel  (in  the  northeast  corner  of  the  Palmer 
(inadrano-le  and  crossing  the  middle  of  Ware),  which  extends  south  into  the 
Ware  River  Valley.  An  inspection  of  the  map  will  show  that  this  channel 
is  tlie  direct  continuation  of  the  Orange-Enfield  valley,  and  it  is  probable 
that  this  longitudinal  valley  was  deeply  excavated  in  pre-Glacial  times 
along  the  course  of  Beaver  Brook,  the  north-south  portion  of  the  Ware 
River,  and  southward  past  Calkins  Pond  and  the  Monson  Valley  into  the 
Willimansett  Valley. 

The  effect  of  the  ice  in  this  position  is  further  seen  in  the  filling  of  the 
high-lying  valley  wliich  runs  south  along  the  east  slope  of  Quabin  Hill, 
which  rises  south  of  Enfield. 

The  sands  that  pass  up  the  West  Branch  of  Swift  River  go  beyond  its 
head  waters  and  end  at  Wendell  Center,  on  the  divide  between  the  Chicopee 
and  iMillers  river  drainages,  in  an  instructive  way.  (See  p.  574.)  The 
broader  sands  of  the  Enfield  basin  go  across  Hampshire  County  into  Frank- 
lin County  and  end  at  Orange,  as  far  north  as,  but  much  lower  than,  the 
West  Branch  sands. 

On  the  map  I  have  given  a  single  color  (1  s)  to  all  the  sands  here  dis- 
cussed, because  they  form  a  continuous  series  with  uniform  slopes  and 
because  they  Avere  plainly  formed  by  a  continuous  series  of  events  which 
can  not  in  mapping  be  conveniently  subdivided.  It  is,  however,  probable 
that  these  two  valleys — the  West  Branch  and  the  Orange-Enfield — remained 
main  drainage  arteries  until  Millers  River,  far  in  the  north,  was  set  free  of 
ice,  and  thus  long  after  the  Ellis  Mills  outlet  was  exchanged  for  the  perma- 
nent Chicopee  River  outlet. 

It  seems,  however,  that  the  broad  basin  was  in  a  sense  filled  stepwise 
from  south  to  north,  so  that  when  the  outlet  was  transferred  from  the  Ellis 
Mills  Valley  to  the  Chicopee  River  Valley  the  Swift  River  began  to  cut 
through  the  sands  already  deposited  and  the  upper  portion  of  the  basin 
remained  still  a  catchment  area  for  the  flood  waters.  I  deduce  this  from 
the  fact  that  the  sands  of  the  Belchertown  plains,  which  have  clear  relation 
to  the  present  drainage  outlet  at  Three  Rivers,  are  derived  entirely  from 


572  GEOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 

Jabish  Brook,  next  west,  and  Swift  River  seems  to  have  joined  this  brook 
from  out  its  gorge  in  the  till,  with  its  waters  clarified  in  an  upper  catch- 
ment basin.  The  Orange-Enfield  basin  has  thus  in  a  sense  an  indejaendent 
history. 

It  is,  of  course,  true  that  the  waters  swept  sands  down  this  broad 
basin  during  all  the  time  the  ice  was  melting  up  it.  It  is  further  probable 
that  the  final  body  of  sand  was  swept  into  the  basin  and  the  final  molding 
and  forming  of  its  surface,  especially  in  its  northern  part,  was  effected 
when  the  ice  had  abandoned  it  and  still  clogged  Millers  River  lower 
down  than  the  head  of  the  basin,  so  as  to  allow  the  drainage  of  the  ujaper 
part  of  the  river  to  enter  this  basin  at  its  northeast  corner  and  also  to 
turn  back  the  lower  drainage  of  the  river  into  the  northwest  corner  of  the 
same  broad  valley. 

The  village  of  Orange  stands  at  the  northwest  corner  of  this  area  of 
flat  sands  and  gravels,  of  which  tlie  raih-oad,  thence  east  nearly  to  Athol,  4 
miles,  is  closely  the  northern  boundary,  and  which  extends  south,  with  an 
average  width  of  nearly  2  miles,  across  New  Salem,  Grreenwich,  Prescott, 
and  Enfield,  to  the  gorge  already  described  (see  p  570),  hj  which  its  waters 
escaped  southwestward.  We  find  the  indication  of  a  large  and  simultane- 
ous influx  of  waters  from  the  northeast  and  northwest  corners  very  clear. 

The  sands  are  494  feet  above  the  sea  at  the  railroad  station  at 
Orange — about  their  lowest  level.  They  continue  east  for  a  long  distance 
as  level,  fine  sands,  and  north  to  the  foot  of  the  rocky  slopes,  where  there 
was  no  dj-ainage  to  bring  in  material.  East,  within  a  mile  of  the  Narrows, 
below  Athol,  one  comes  on  the  face  of  a  great  delta  (occupied  by  Millers 
River)  sent  out  into  the  plain,  terraced  on  its  front  at  a  height  of  about  30 
feet  above  the  plain  below,  but  reaching  a  height  of  60  feet  at  the  delta 
front  and  rising  slightly  to  the  Narrows.  On  the  north  the  delta  extended 
across  the  mouth  of  a  small  valley,  ponding  the  waters  back  and  forming 
extensive  clay  beds,  in  which  the  following  section  was  exposed. 

Section  in  brickyard  at  the  Ifarroios,  in  Athol. 

Feet. 

Thin  sands 6 

Buff  clays  .  .  - 6 

Thin-bedded  blue  clays,  no  bottom  seen 6 

On  the  west  the  indication  of  the  influx  of  the  waters  is  equally  clear. 


THE  WAKE  AND  8VV1FT  ItlVER  LAKES.  573 

Fi-imi  \\\'ii(l(,-ll  (Ic'iJdt  up  (1)'",  PI.  XXXV,  C),  the  liigk  level  sands  were 
t'uniu'iU  nlainh'oontiuuous  acniss  the  valley.  Their  inner  structure  indicates 
a  flow  to  the  east  and  their  upper  surface  slopes  in  this  direction.  They 
are  about  i'O  feet  high  at  the  Moss  Brook  delta.  At  tlie  Scotts  or  Orcutts 
Brook  delta,  next  east  and  opposite  this  latter,  they  extend  down  the 
Ilolshire  lload  Valley,  the  next  valley  on  the  south  parallel  to  and  west  of 
the  main  channel,  at  a  heig-ht  of  75  feet  above  the  plain,  filling  this  valley 
with  a  o-reat  body  of  sands  and  gravels,  which  are  beautifully  kettle-holed 
south  of  North  Pond,  and  which  extend  south  to  join  the  main  Orange- 
Enfield  channel  in  New  Salem. 

The  hio-h  sands  which  thus  fill  the  Holshire  Road  Valley  extend  round 
the  north  spur  of  Walnut  Hill,  which  separates  this  valley  from  the  main 
Orange  Valley,  and  project  out  freely  into  the  latter  in  a  delta  which 
matches  that  at  the  other  corner  and  which  along  the  north  side  of  the 
river  is  confluent  with  the  delta  of  Fall  Hill  Brook,  on  which  the  cemetery 
is  built. 

A  section  of  the  sands  east  of  Orange  showed  a  great  thickness  of  fine 
sands  with  the  cross-bedding  dipping  eastward;  above  this  a  bed,  about  2 
feet  thick,  of  verj^  fine  sands.  This  was  covered  in  turn  with  coarse  sands 
of  about  the  same  thickness,  the  boundary  between  the  two  beds  being 
very  irregular  and  the  structure  indicating  a  delta  front  advancing  from 
the  west. 

The  last  halting  place  of  the  ice  in  the  Swift  Biver  drainage  area. — The 
position  of  the  ice  on  Millers  River  at  the  time  of  this  last  effective  flood- 
ing of  this  portion  of  the  area  can  be  closely  fixed  at  Wendell  station  (b^^), 
and  the  coincident  ice  front  can  be  traced  across  from  the  Connecticut  to 
the  northeast  corner  of  Warwick  by  the  following  considerations : 

Going  up  Tannery  Brook  (a  branch  of  Goddard  Brook)  from  Montague 
village,  one  comes  at  the  "height  of  land"  on  a  broad  area  (1  ^")  of  heavy 
sands  and  gravels  southwest  of  Dry  Hill,  bedded  and  with  iiTCgular  sm-face. 
They  extend  down  to  where  ice  filling  the  Connecticut  Valley  would 
have  stopped  them,  and  there  end  abruptly.  Ofi"  to  the  south  a  col  west 
of  Chestnut  Hill  determined  their  height  and  provided  for  their  outflow; 
to  the  north  they  end  at  a  schoolhouse  (b",  PI.  XXXV,  C),  and  here  one 
can  look  north  down  an  open  bowlder-covered  valley,  wholly  free  from 
sand,  which  must  have  been  filled  with  ice  when  the  sand  beds  just  ])assed 


574       GEOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 

over  were  dejjosited.  Farther  east  Osgood  Brook,  in  Wendell,  has  heavy 
sands  at  its  south  end,  while,  as  before,  the  open  valley  to  the  north  extend- 
ing to  the  Millers  River  Valley  is  bowlder-covered  and  free  from  sands. 
These  sands  terminate  a  little  farther  north  than  those  last  mentioned. 

Next  east  one  may  follow  up  the  deep  V-shaped  valley  of  Wickett 
Brook  from  where  it  joins  Millers  River  south  and  find  it,  although  well 
fitted  to  retain  sediments  and  although  continued  north  of  Millers  River  in 
a  deep  valley,  to  be  bowlder-covered  to  the  water's  edge.  At  a  point  a 
little  north  of  the  one  reached  in  the  last  brook,  the  high-level  bowlderj^ 
gravels  (1  s)  begin  and  increase  and  accompany  the  brook  south  to  its 
headwaters  west  of  Wendell  Center  and  beyond,  and,  passing  over  the  col 
in  the  deep  continuous  valley,  they  continue  south  to  join  the  heavy  sand 
beds  north  of  Locks  Pond. 

On  the  next  brook  east — a  second  Osgood  Brook — the  brook  bed  is  till 
covered  to  a  point  nearly  as  far  south,  and  then  sands  commence  which  run 
up  the  valley,  increasing  as  the  brook  lessens,  and,  passing  its  col  in  the  val- 
ley, as  before,  they  are  continued  down  the  valley  of  Swift  River.  The 
streams  which  enter  Millers  River  from  the  north,  across  Erving,  opposite 
those  described  above,  have  inconsiderable  sand  deposits.  Furthermore, 
the  Millers  River  Valley  up  to  Wendell  station  has  small  deposits  of 
high-level  sands.  With  the  next  brook  east,  however,  this  is  changed. 
The  brooks  thrust  extensive  deltas  into  the  valley,  and  from  this  point  on 
east  the  drainage  Avas  plainly  eastward  into  the  Orange  basin,  as  will  be 
detailed  below. 

Examining  the  upper  waters  of  the  first  brook  east  (Moss  Brook)  com- 
ing down  from  the  north,  we  see  the  sands  begin  on  its  western  tributary 
a  half  mile  above  Harris  Pond,  and  on  the  main  stream  at  the  mill  pond 
(Lake  Moore)  southwest  of  Warwick  Center,  while  the  valleys  above  are 
empty  of  sands.  Below  these  points  the  stream  is  bordered  by  heavy 
gravels  and  sands  (1  s),  flat  topped,  with  a  width  for  a  long  distance  of  150 
rods,  expanding  in  the  southwest  of  Warwick  to  a  triangular  sand  plain 
more  than  a  mile  on  a  side  before  it  enters  its  narrow  gorge  to  reach  the 
main  valley. 

Following  the  brook  still  farther  north  tln-ough  the  narrow  valley 
south  of  Mount  Grrace,  we  soon  find  it  again  bordered  by  broad  sands, 
which  expand  to  an  extended  sand  plain  that  continiTes  north  of  Warwick 
beyond  the  headwaters  of  this  brook  and  that  is   soon  trenched  b)^  the 


THE  GHICOPEE  KIVEK  DRAINAGE.  575 

upinT  wiitL'i's  of  Mountain  Brook,  H<i\vin<j;-  north.  Following  this  brook  for 
a  lon»-  distance  with  the  sands,  the  latter  end  abruptly  and  overhang  Sunny 
Vallev,  wliich  was  plainly  filled  with  ice  when  these  sands  were  laid  down 
'I'lii'  bottom  of  Sunny  Valley,  far  below,  is  also  covered  with  the  fine- 
o-rained,  Hat  sands  of  a  still  later  lake. 

On  Tully  River,  the  last  of  the  series,  the  sands  begin  where,  in  the 
east  of  Warwick,  the  Royalston  road  crosses  the  river  (b",  PI.  XXXV,  C). 
Above,  the  deep,  open  vallej'  is  continuous  a  long  way  north  in  two 
branches,  ftivorably  shaped  and  situated  to  receive  and  retain  sands,  but 
now  covered  with  coarse  bowlders.  Drawing  a  line  through  the  points 
thus  fixed  in  the  preceding  paragraphs  from  Tannery  Brook  in  Montague 
(p.  573)  to  Tully  River  (see  PI.  XXXV,  C),  and  assuming — which  admits 
of  little  doubt — that  they  represent  points  along  a  continuous  ice  front,  we 
see  that -while  the  ice  still  projected  in  a  lobe  down  the  Connecticut  Valley 
the  ice  front  extended  toward  the  northeast  from  Montague  and  pressed 
forward  in  a  blunt  lobe  between  Mount  Grace  in  Warwick  and  Bear  Hill 
in  Wendell.  See  also  page  604  for  the  continuation  of  this  barrier  on  the 
west  of  the  Connecticut  Valley. 

THE  CHICOPEE  RIVER   DRAINAGE. 
THE   BBLCHBRTOWN   LAKE. 

With  the  breaking  down  of  the  barriers  (b'',  PI.  XXXV,  D)  described 
abovd,  the  Quaboag,  Ware,  and  Swift  rivers  were  admitted  to  the  Belcher- 
town  plateau  and  became  tributaries  of  the  Belchertown  Lake.  Standing  in 
the  middle  of  the  broad,  square  plain  of  fine  sands  which  stretches  east  from 
Three  Rivers,  we  are  shut  in  on  the  east  and  south  by  high,  rocky  hills 
notched  for  the  passage  of  the  three  streams  mentioned  above,  and  on  the 
west  by  a  broad,  low  ridge  which  on  its  west  side  slopes  down  to  the  valley 
of  the  Connecticut.  At  the  southwest  corner  the  western  ridge  sinks 
■  down,  and  the  lake  was  ultimately  drained  at  this  jjoint,  the  Chicopee  River 
cutting  a  deep  canyon  in  till  and  rock  to  join  the  Connecticut,  and  its 
three  branches  dissecting  the  old  lake  bottom  and  showing  how  great 
was  the  volume  of  sand  gathered  there.  It  was  so  great,  indeed,  that  they 
nowhere  cut  through  it.  The  lake  extended  up  the  valleys  of  each  of  these 
three  rivers  in  the  form  of  broad  erosion  plains  on  each  side  of  the  streams, 
commencing  at  the  same  level  with  the  lake  sands  and  rising  slowly  with 
the  streams. 


576       GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

If  we  look  north  we  see  the  sands  divide  on  the  ridge  on  wliich  the 
village  of  Belchertown  is  built,  an  eastern  lobe  passing  up  the  broad  valley 
in  which  Jabish  Brook  now  flows,  the  other  running  north  at  the  western 
foot  of  the  ridge.  While  the  three  southern  streams  were  now  normal 
tributaries  of  the  lake,  disturbed  by  ice  only  in  their  upper  reaches  or  not 
at  all,  these  two  northern  lobes  were  the  place  of  entrance  of  two  tributary 
streams  which  came  down  in  courses  largely  supplied  by  the  ice  itself. 

Following  up  the  east  of  these  lobes  we  find  it  continuing  east  of 
Belchertown  village  with  a  width  of  above  half  a  mile,  and  northeast  of  the 
village  widening  into  a  still  more  extensive  area  of  coarse  sands  of  great 
thickness — a  filled-up  lake  at  a  high  level — and  then  continuing  northward 
in  the  narrow,  deep  valley  of  Jabish  Brook  as  a  broad  sand  flat  on  either 
side  of  and  much  higher  than  the  brook  and  rising  rapidly  until,  coming 
out  on  the  higher  ground,  it  widens  and  makes  a  broad  curve  to  the  west 
and  again  to  the  north,  in  the  extreme  north  of  Belchertown,  and  continues 
north  in  Pelham,  through  the  high  valley  east  of  the  asbestos  mine,  to  join 
the  high  terrace  in  the  Pelham  basin  described  later  (p.  578).  When  it 
makes  the  second  curve  to  the  north  it  sends  down  a  lobe  to  the  south,  and 
it  is  here  unsupported  upon  the  west  by  any  rocky  shore  line,  but  dips 
westward  in  a  great  terrace  (b",  PI.  XXXV,  D).  It  was  here  plainly  sup- 
ported for  a  time  by  the  ice  which  still  filled  the  Connecticut  Valley  to  the 
west,  and  on  the  breaching  of  this  support  the  waters  ran  down  along 
the  west  side  of  the  ridge,  instead  of  the  east,  as  before,  cutting  a  terrace 
in  the  sands  already  deposited,  and,  walled  on  the  west  by  ice,  joined  the 
Belchertown  Lake  by  the  western  lobe  as  detailed  below,  running  south 
across  the  ice  which  filled  the  notch  at  the  east  end  of  the  Hoi  yoke  range. 

Starting  at  its  south  end,  one  can  follow  the  western  lobe  north  past 
Belchertown  village  for  nearly  3  miles,  and  at  the  railroad  station  it  is  471 
feet  above  the  sea.  The  low  range  then  forming  its  western  boundary  sinks 
down  to  the  level  of  the  plateau,  and  the  plateau  itself  comes  to  a  sudden 
termination  on  a  line  (b*,  PI.  XXXV,  D)  which  runs  northeast  from  the  end 
of  this  range  to  join  the  Belchertown  range.  Standing  anywhere  on  this 
line,  one  is  at  the  north  end  of  the  sands,  and  looks  down,  across  a  broad, 
sloping  area  of  till  and  rock,  quite  free  from  any  covering  of  sands,  upon  a 
billowy  surface  of  "reticulated  ridges"  at  337  feet  above  sea,  which  con- 
tain the  Belchertown  ponds,  and  lower,  beyond  these,  to  the  west,  upon  the 
eastern  edge  of  the  highest  terrace  flat  of  the  Connecticut  at  about  290  feet. 


THE  BELOHERTOWN  LAKE.  577 

Wo  have  been  following  iip  a  tributary  of  the  Belchertown  Lake  to 
this  phu-e,  and  we  find  here  that  the  ground  drops  away  more  than  150  feet 
below  its  level.  Looking  north  through  the  pass  formed  by  the  east  end 
of  the  Holyoke  range  and  the  continuation  of  the  Belchertown  ridge  on 
our  right,  we  see  that  the  latter  ridge,  just  north  of  the  pass  and  above 
Dwight's  station,  runs  behind  (east  of)  a  new  ridge  (the  ridges  stand  en 
(Echelon  in  reference  to  the  valley  of  the  Connecticut,  having,  as  they  run 
north,  a  little  more  easting  than  it).  Between  these  ridges  is  a  high  valley, 
in  which  is  the  continiTation  northward  of  the  stream  bottom  we  are  follow- 
ing, the  two  parts  facing  each  other  across  the  low  pass  of  the  Belchertown 
ponds  like  the  broken  ends  of  a  Roman  aqueduct.  A  mountain  brook  has 
now  cut  a  deep  gorge  in  this  valley  in  till,  which  is  almost  as  compact  as 
rock,  but  this  is  only  a  central  notch  in  a  flat-bottomed  valley  which  ends 
southwardly  quite  abruptly  above  Dwight's  station,  and  which  is,  in  fact, 
the  point  in  the  eastern  lobe  just  described  (p.  576),  where  the  breaching  of 
the  channel  deflected  the  outflow  down  the  west  of  the  ridge  to  our  place 
of  observation.  This  channel  is  water-molded  and  covered  with  bars  and 
sand  flats,  exactly  as  is  its  southern  portion  in  Belchertown,  and  one  may 
follow  it  up  past  the  asbestos  mine,  east  of  which  the  rocky  ridges  are 
smoothed  into  reefs  and  covered,  by  gravel  bars,  until  it  merges  into  the 
second  great  terrace  (1  p,  PI.  XXXV,  C)  of  the  Pelham  basin.  Standing 
here,  or,  better,  on  the  east  end  of  the  Holyoke  range,  one  can  see  that  the 
ice  must  have  still  filled  the  valley  of  the  Connecticut  both  north  and  south 
of  the  Holyoke  range,  and  must  have  rested  with  a  depth  of  above  150  feet 
in  the  low  pass  of  the  Belchertown  ponds,  so  that  the  stream  draining  the 
Pelham  basin  ran  between  the  point  where  its  bed  breaks  down  suddenly 
above  Dwight's  station  to  where  it  begins  again  in  Belchertown,  with  its 
eastern  bank  the  Belchertown  ridge,  its  bottom  and  western  bank  of  ice. 

It  is  clear,  finally,  that  the  melting  of  the  ice  back  across  the  low 
western  ranges  which  bounded  the  lake  in  Belchertown  at  last  gave  this 
body  of  water  a  new  way  of  exit  through  the  course  of  Broad  Brook,  which 
runs  down  through  the  middle  of  these  ranges  and  joins  the  Chicopee  where 
it  turns  south  in  the  same  longitudinal  valley  as  that  of  the  brook  itself, 
and  that  the  further  retreat  of  the  ice  let  the  waters  pass  outside  (west  of) 
these  ranges  entirely 

MON  XXIX 37 


578 


GEOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 


THE  PELHAM  LAKE  AND  ESKBE. 


Opposite  Amherst  the  frontal  range  of  gneiss  which  bounds  the  valley 
is  partly  broken  down,  and  a  narrow  portal  opens  into  a  great,  rounded 
upland  valle}^  or  clough,  about  conterminous  with  the  boundaries  of  the 
town  of  Pelham.  (See  1  p,  1  p^  PI.  XXXV,  C,  and  fig.  32.)  North  and 
south  the  high  level  is  continuous  and  is  grooved  by  shallow  valleys.  The 
two  on  the  north  admitted  the  glacial  waters  to  the  lake,  the  one  on  the 
south  gave  them  egress  to  the  Belchertown  Lake,  as  detailed  a  few  para- 
graphs back  (p.  576). 

The  rocky  bottom  of  the  basin  is  about  560  to  580  feet  above  sea,  and 
it  is  filled  up  with  coarse  till  to  a  quite  level  surface  at  640  to  650  feet,  and 


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Pia.  32.— Pelham  Lake  section.    A  generalized  section  from  Swift  Eiver  to  Fort  Elver  at  East  Street,  drawn  through 
Pelham,  showing  the  different  outlets  of  the  Pelham  lakes. 

this  heavy  deposit  covers  the  whole  southern  slope  of  the  basin.  From 
any  point  high  up  on  this  slope,  as  on  the  road  to  the  well-known  mineral 
locality,  the  asbestos  mine,  one  sees  massive  accumulations  of  sand,  much 
of  it  very  fine  and  all  well  sorted,  which  rise  in  a  series  of  terraces  of 
great  regularit}'',  with  broad,  flat  surfaces  and  flat  scarps,  to  a  height  of 
1,000  feet  on  the  east  side  and  830  feet  on  the  north  and  west  sides  of  the 
basin,  and  are  almost  wholly  wanting  on  the  south  side.  Westward,  the 
highest  terraces  end  abruptly  when  they  come  to  the  entrance  of  the  basin. 
At  a  lower  level,  500  feet  above  sea,  they  seem  to  stretch,  in  the  portal 
terrace,  right  across  this  entrance,  like  a  great  earthen  dam — the  narrow 
notch  which  the  brook  has  cut  being  scarcely  visible — and  they  dip  steeply 


THE  PELHAM  LAKE  AND  ESKER.  679 

down  into  the  basin  toward  the  east  in  a  series  of  beautiful  terraces,  and 
on  tlie  opposite  side  descend  in  a  series  of  terrace  scarps  and  irregular 
slopes  to  the  level  of  the  normal  high  terrace  of  the  Connecticut  River, 
at  290  to  295  feet.  Looking  across  to  the  northern  horizon,  one  sees  two 
slight,  broad  depressions  in  the  line  Avhich  joins  the  eastern  and  western 
bounding  ridges — by  Avhich  the  two  roads  pass  north  from  Pelham  to 
Shutesbury — and  these  mark  the  southern  termini  of  two  valleys  by  which 
the  waters  which  deposited  the  sands  entered  the  basin.  Their  elevation 
at  the  southern  end,  where  they  open  into  the  basin  and  whence  the  terrace 
sands  extend  southwardly,  is  820  feet  above  sea,  and  they  run  far  north, 
rising  slowly  and  showing  abundant  traces  of  the  passage  of  the  waters 
in  their  shape  and  in  the  tails  of  sand  which  lie  in  the  lee  of  projecting 
rocks. 

But  the  most  remarkable  deposit  of  all  is  a  great  ridge  (k)  of  yellow 
sand  (see  PI.  XIII),  40  to  50  feet  high,  which  starts  from  the  mouth  of  the 
eastern  of  these  channels  and  stretches  down  the  slope  of  the  basin  south- 
ward with  sinuous  course,  bending  at  last  westward  and  skirting  the  brook 
and  running  for  a  long  distance  out  upon  the  till  of  the  valley  bottom,  from 
which  it  is  as  sharp)ly  demarcated  as  a  new  railway  embankment  thrown 
across  a  grassy  field.  This  ridge  has  sharp  slopes  on  either  side,  and  ends 
abruptly  far  in.  advance  of  the  remaining  terrace  sands.  Much  of  it  is  a 
rather  coarse  sand,  or  rather  a  sand  with  many  pebbles,  and  rarely  a  great 
bowlder  is  embedded  in  it.  It  drops  by  great  steps,  so  that  one  is  at  first 
uncertain  whether  to  consider  it  an  esker  in  the  sense  now  current,  or  to 
think  it  a  section  of  the  ordinary  terrace  sands,  from  which  streams  cutting 
back  into  the  mass  on  either  side — their  waters  being  held  up  to  the  sand 
level  by  the  subjacent  till — have  removed  so  much  of  the  loose  material 
that  this  long  ridge  remains  as  an  index  of  the  former  greater  extension  of 
the  sands  toward  the  center  of  the  valley. 

The  entire  freedom  of  the  broad  bottom  of  the  basin  from  sand  or 
clay,  and  the  great  improbability  that  any  such  deposit  has  ever  been 
present  and  been  so  entirely  removed  that  no  trace  or  indication  of  its 
presence  or  of  any  erosion  by  which  it  can  have  been  removed  is  discern- 
ible, make  it  far  more  probable  that  the  first  explanation  is  the  true  one, 
and  that  it  is  a  deposit  in  a  temporary  ice  channel,  dropped  by  the  melting 
of  the  ice  on  the  steep  slope  down  which  it  now  winds  like  a  great  snake. 


580  GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

Indeed,  its  uniform  size  for  so  long  a  distance  scarcely  admits  of  any  other 
explanation.  This  is  represented  on  PI.  XXXV,  C,  and  its  end  appears  in 
the  section,  fig.  32,  p.  578. 

The  next  striking  peculiarity  is  that,  while  the  grand  terraces  are 
heaped  high  on  the  east,  north,  and  west  of  the  basin,  and  across  its 
western  portal,  the  flat  bottom  is,  and  has  always  been,  bare  till,  and 
scarcely  a  trace  of  sand  can  be  seen  upon  the  south  slopes — nowhere 
enough  to  mark  the  water  stand.  Finally,  the  highest  terrace  on  the  east, 
at  1,000  feet,  has  no  counterpart  on  the  other  side. 

I  have  expressed  upon  the  map  (PL  XXXV,  C)  the  explanation  which 
seems  to  me  most  plausible,  so  far  as  this  was  possible.  In  the  first  place, 
the  highest  sands  on  the  east  of  the  basin,  at  1,000  feet,  seem  to  have  been 
deposited  by  waters  coming  down  the  eastern  of  the  two  northern  valleys 
when  the  basin  was  still  nearly  filled  with  ice,  and,  as  these  sands  are  on 
the  same  level  as  the  lowest  portion  of  the  ridge  to  the  east,  the  waters 
would  seem  to  have  escaped  east  into  the  West  Branch  Valley.  This 
lowest  ground  is  just  north  of  the  section  line.  The  ice  barrier  (b  8,  PI. 
XXXV,  C)  placed  on  these  lake  beds  (1  p^  PI.  XXXV,  C)  may  well  have 
been  somewhat  farther  west,  as  the  lower-level  waters  have  worn  into  and 
terraced  these  sands  on  the  west. 

Some  temporary  posture  of  the  ice  turned  the  waters  of  this  eastern 
stream  otit  across  its  surface  in  a  course  directed  toward  the  portal,  and 
the  sand  filling  this  channel  sank  to  form  the  great  esker  as  the  ice  melted. 
With  the  retreat  of  the  ice  from  the  basin  the  asbestos  mine  valley  on 
its  south  rim  was  set  free  at  a  level  of  830  feet  above  the  sea,  furnishing 
a  permanent  waste  weir  for  its  waters  south  into  the  Belchertown  Lake, 
along  the  course  described  on  page  576,  and  as  the  ice  still  filled  the  whole 
Connecticut  Valley  opposite,  it  completed  the  barrier  across  the  portal  on 
the  west.  The  lake  basin  was  then  rapidly  filled  by  sands  pushed  south 
as  great  deltas  from  the  two  northern  valleys,  and  the  waters  coming  down 
from  the  north  between  the  ice  and  the  west  slope  of  Hygeia  entered  the 
basin  at  the  portal  and  sent  a  third  delta  into  the  basin,  thus  completing  the 
terrace  on  the  western  side.  The  life  of  the  lake  at  this  stage  was  a  very 
brief  one,  and  when  the  deltas  had  advanced  halfway  across  the  bottom  the 
ice  barrier  (b^)  failed  at  the  portal  and  the  waters  escaped,  breaching  the 
portal  terrace  and  moving  south  by  a  channel,  still  well  marked,  which  runs 


THE  PELHAM  LAKE  AND  ESKER.  581 

south  from  the  Orient  House  ceUar.  The  duration  of  the  waters  was  so 
brief  that  httlo  or  notliiny  was  deposited  ui)ou  the  till  over  the  center  of  the 
basin,  or  so  little  that  it  has  been  removed  by  wind  and  rain.  Yet,  starting 
from  this  flat  bowlder-covered  bottom  of  the  basin,  one  toils  up  more  than 
a  mile  over  the  slope  of  fine  sand  of  the  Shutesbury  road  to  the  top  of  the 
delta  at  the  mouth  of  the  western  valley,  and  on  the  other  side  one  can  step 
from  an  ice-bowlder  onto  the  steep  sand  slope  of  the  esker,  so  sharp  is  the 
boundary. 

If  one  stands  on  the  south  slope  of  the  valley  and  examines  the  great 
sand  rampart  already  described,  which  is  tlii-own  across  the  portal,  it  seems 
still  intact  as  when  the  ice  left  it.  The  narrow  notch  which  the  brook  has 
cut  deeply  tln-ough  it  is  barely  visible.  The  terrace  surfaces  slope  5°  east- 
ward into  the  basin  across  the  portal,  as  they  do  in  their  northward  pro- 
longation where  they  abut  on  the  ridge  of  Hygeia  to  the  west. 

Fortunately  the  ditch  for  the  main  of  the  Amherst  waterworks  ran 
from  the  west  across  the  flat  where  the  ice  rested  at  the  entrance  of  the 
portal  (Pelham  City),  giving  a  complete  section  of  the  semimorainic  beds 
that  rested  on  the  ice  with  all  their  irregularity.  It  continued  past  the 
Orient,  exposing  the  passage  beds  to  the  fine  della  sands,  and,  passing  high 
up  above  the  brook  into  the  notch  which  this  brook  has  cut  into  the  portal 
or  entrance  terrace,  it  continued  along  its  southern  slope  through  the  whole 
delta  deposit  and  far  out  into  the  central  portion  of  the  basin.  At  first,  and 
nearest  the  ice,  the  beds  dipped  west,  and  these  may  be  "backset"  beds,  as 
Prof  W.  M.  Davis  would  say,^  or  may  have  taken  this  posture  as  a  result  of 
the  melting  of  the  ice  beneath  and  their  sinking  westwardly.  For  the 
most  part  the  beds  dip  strongly  east  into  the  basin  and  show  that  the  cur- 
rent came  from  the  west — that  is,  from  the  ice. 

I  append  a  detailed  description  of  the  beds,  written  when  I  had  no 
clear  view  of  the  meaning  of  the  whole.  A  describes  the  till-covered  flat 
outside  the  portal;  B,  the  sands  and  gravels  deposited  against  and  on  the 
retaining  wall  of  ice  and  confused  by  its  melting,  which  occur  in  decreasing 
amount  eastward;  C,  the  finer  eastward-dipping  delta  sands  to  their  ending 
in  the  center  of  the  lake.  The  section  runs  parallel  to  and  a  little  north  of 
the  section  given  (fig.  32,  p.  578)  where  the  gneiss  ridge  southwest  of  the 


'  Beds  taking  this  western  dip  because  they  were  deposited  by  waters  escaping  from  beneath 
the  ice  with  eastward  and  upward  direction. 


582  GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

Orient  cellar  has  dropped  down  and  is  covered  with  till,  while  the  sands  at 
the  Orient  cellar  drop  by  a  sharp  slope  to  those  of  the  highest  terrace  of  the 
Hadley  Lake. 

A. — At  the  first  house  in  the  west  village  of  Pelham,  about  320  feet 
above  the  sea  level,  the  last  trace  of  the  highest  bench  of  the  Amherst 
basin  (the  Hadley  Lake)  disappeared,  and  through  the  village,  eastward 
into  the  notch,  the  coarse  till  made  the  surface  to  the  point  where  the 
Shutesbury  road  branches  off,  as  has  been  described  on  page  581. 

B. — Here  the  till  goes  under  sands  and  continues  about  horizontal  or 
rising  slightly  for  a  long  distance  eastward,  so  that  the  increased  elevation 
of  the  surface  is  to  be  referred  wholly  to  the  thickening  of  the  overlying 
sands. 

Beginning  at  the  Shutesbury  road  the  sands  are,  for  a  distance,  thin, 
and  contain  here  and  there  a  large  stone — the  largest,  1  foot  in  diameter. 
They  then  thicken  to  70  feet  (fig.  32),  and  hold  this  thickness  past  the 
Orient  House  cellar.  Where  they  begin  to  thicken — at  the  house  west  of 
the  Orient — clean-washed,  dry,  whitish  sand  appears  in  layers  from  6  to  12 
inches  thick,  dipping  10°  W.,  alternating  with  layers  of  washed  gravel  2 
feet  thick  containing  many  pebbles  up  to  6  inches,  and  rarely  one  a  foot,  in 
diameter.  The  sand  layers  are  evenly  stratified  and  show  no  finer  struc- 
ture. Sometimes  a  sand  layer  waves  up  and  down,  and  the  gravel  layer 
above  thickens  to  fill  the  depression.  A  little  farther  east  one  layer  of 
fine,  well-washed  gravel — the  pebbles  averaging  1  inch — grades  westward 
into  sand  and  eastward  into  6 -inch  gravel.  All  along  in  front  of  the  Orient 
House  the  cutting  was  mostly  in  sand,  showing  most  beautiful  and  con- 
torted flow-and-plunge  structure,  the  dip  of  the  laminae  being  20  to  30°  E., 
as  if  urged  by  a  rapid  current  from  the  west. 

Much  of  the  way,  however,  the  whole  is  thrown  into  great  confusion. 
Layers  of  sand  a  foot  thick,  with  fine  false  bedding,  stand  directly  on  tlieir 
heads  or  are  variously  twisted  in  the  gravel,  or  the  sand  cuts  off  vertically- 
against  the  gravel,  and  vice  versa.  In  one  case  a  band  of  gravel  2  feet 
wide  was  intruded  into  the  sand  like  a  dike;  in  another  a  mass  of  sand  8 
feet  wide  occupied  the  same  position  in  the  gravel,  as  if  the  water  had 
worn  a  channel  in  the  frozen  gravel  and  filled  it  with  its  own  sands. 

Leaving  the  road  at  the  Orient  House  the  ditch  passed  across  the 
flat  field  in  front  of  the  house,  the  beds  growing  finer  in  grain  and  the 
disturbances  gradually  diminishing. 


THE  PELHAM  LAKE  AND  ESKER.  583 

Up  to  tliis  point  the  section,  after  reaching'  the  sand,  has  crossed  the 
j)l;iiu  of  the  Orient  House  (shown  in  fig.  32,  p.  578),  a  pUiin  whose  surface 
has  been  produced  by  a  later  erosion.  The  sands  exposed  in  the  cutting, 
however,  are  a  part  of  the  entrance  terrace,  and  their  irregularity  seems 
due  to  their  dei)()sition  against  or  upon  a  shifting  barrier  of  ice. 

C. — From  here  the  section  continues  at  the  level  of  this  plain  along  the 
north  slope  of  the  notch  cut  by  the  brook  in  the  portal  terrace,  about  40 
feet  below  the  surface  and  60  feet  above  the  brook,  and  for  a  long  distance 
runs  in  clean-washed,  very  fine  white  sand,  laid  horizontally  in  broad,  flat 
lenticular  masses,  1  to  6  inches  thick  and  many  feet  long,  with  clayey 
boundaries  which  projected  on  slight  weathering.  It  preserves  everywhere 
its  original  delicate  structure  undistui'bed. 

Eastward  the  hill  is  cut  down  by  erosion  and  the  ditch  sinks  on  its  side, 
showing  these  fine  sands  to  be  in  great  force  and  to  rest  upon  till,  through 
which  the  ditch  passes  a  short  distance  and  rises  along  the  side  of  a  second 
hill  and  continues  in  the  sands.     There  was  exposed  the  following  section : 

1.  Below,  a  very  fine  white  sand,  in  layers  4  to  6  inches  thick,  which 
ran  with  very  slight  undulations  for  20  feet  or  more,  and,  thinning  out,  were 
replaced  by  others.     This  was  exposed  in  a  thickness  of  1  to  2  feet. 

2.  Above,  for  2  feet,  was  the  same  fine  sand,  but  showing  a  most  deli- 
cate and  beautiful  flow-and-plunge  structure,  the  laminae  dipping  20°  E. 
Above,  this  sand  is  limited  by  an  imdulating  surface  of  erosion  upon  which 
rests — 

3.  Two  feet  of  coarser  sand,  slightly  reddish,  with  sharp  regular  cross 
bedding,  which  dips  30°  E.  By  the  weight  of  the  sliding  bank  above,  this 
has  been  compressed  into  curious  corrugations. 

The  ditch  rises  and  sinks  in  the  steep  hillside,  and  the  lower  horizontal 
sands  (1)  can  be  traced  for  40  rods  eastward  and  are  present  in  considerable 
thickness.  The  coarser  sands  (2)  extend  probably  to  the  top  of  the  hill, 
about  30  feet. 

A  specimen  of  the  sand  taken  from  the  lowest  bed  (1)  was,  when 
dried,  like  the  finest  corundum  flour,  and  consisted  of  sharp,  transparent 
quartz  grains  0.03  to  0.04"'"  in  diameter,  with  here  and  there  a  scale  of 
wine-yellow  biotite. 

The  flow-and-plunge  stnicture  of  the  upper  portion  of  the  fine  sand, 
dipping  to  the  east,  indicates  a  current  coming  from  the  west,  and  to  this 
current  we  may  attribute  the  erosion  which  prepared  the   surface  upon 


584  GEOLOGY  OF  OLD  HAMPSHIEE  COUFTT,  MASS. 

which  the  coarser  sands  (3)  were  deposited,  and  the  eastern  dip  in  these 
indicates  also  that  the  current  continued  to  flow  eastward,  or  toward  the 
center  of  the  lake. 

THE  HADLEY  LAKE  DRAINAGE. 
THE   LBVERETT   LAKE   AND    THE   NOTCH   EAST   OF   MOUNT   TOBY. 

The  last  of  the  considerable  deposits  (m  t)  at  hig-h  level  on  the  eastern 
side  of  the  valley  dependent  upon  the  obstructed  drainage  which  attended 
the  retreat  of  the  ice  occupies  the  long,  narrow  valley  along  the  west  border 
of  the  Belchertown  quadrangle,  which  runs  north  by  the  village  of  Leverett, 
along  Pond  Brook,  and  past  the  entrance  to  "Rattlesnake  Gutter,"  and 
extends  south  across  the  town  line  into  Shutesbury,  skirting  Mount  Boreas 
on  the  east  and  ending  just  south  of  this  mountain,  where,  south  of  42°  25', 
the  north  branch  of  Fort  River,  which  occupies  the  lake's  former  outlet, 
passes  into  a  canyon  to  reach  the  open  valley  above  East  Street  village,  in 
Amherst.  This  lake  was  early  filled  with  sands,  and  the  waters  carried 
their  surplus  into  the  valley,  contributing  to  form  the  abnormally  abundant 
sands  of  the  high  terrace  of  the  main  valley  a  mile  north  of  East  Street 
village.  One  follows  the  heavy  sands  from  Boreas  northward,  filling  the 
valley  clear  across,  until,  just  on  the  Leverett  line,  they  are  carried  away 
entirely  by  Roaring  Brook,  which  comes  out  of  the  mountains  on  the  east 
and  has  worn  out  a  deep  circular  basin  in  the  lake  deposits,  cutting  them 
clear  across,  and  escapes  through  a  deep,  narrow  transverse  valley  into  the 
valley  of  the  Connecticut.  The  high  lake  beds  extend  a  little  way  down 
this  valley  and  stop  abruptly,  and  it  is  clear  that  the  lake  could  have 
existed  only  so  long  as  the  ice  remained  to  dam  this  outlet.  Two  miles 
north  of  Leverett  Center  and  opposite  Rattlesnake  Gutter,  there  is  a  passage 
connecting  it  with  the  deep  valley  which  runs  down  the  east  side  of  Mount 
Toby,  and  by  which  the  waters  which  entered  this  latter  valley  were 
diverted  into  the  Leverett  Lake. 

The  lay  of  the  beds  in  this  Mount  Toby  Valley  is  very  peculiar  and 
interesting;  a  deep  water-cut  canyon  runs  the  whole  length  of  the  valley 
between  the  conglomera,te  and  the  crystalline  rocks,  and  as  a  brook  runs 
south  in  its  southern  part  and  another  north  in  its  northern  portion,  while 
its  center  is  without  flowing  water,  it  is  clear  that  it  was  not  formed  by 
the  present  streams. 


THE  HADLEY  LAKE  DRAINAaE.  585 

In  the  iitirtidu  of  the  valley  south  of  the  entrance  of  the  side  valley 
troni  the  Leverett  Lake  this  canyon  is  bordered  by  rough  ledges  and  till. 
North  of  this  the  sands  coining  out  of  the  side  valley  fill  the  main  valley 
from  side  to  side  Avith  a  great  volume  of  coarse  sands,  cut  only  by  the 
nortlnvard  prolongation  of  the  canyon  already  noted.  These  sands  pre- 
serve for  a  long  way  a  flat  surface,  but  as  they  approach  the  north  end  of 
the  Mount  Toby  Valley  they  become  gradually  kettle-holed  on  a  grand 
scale,  and  as  the  valley  widens  the  sands  widen  also  and  preserve  their 
lieight,  400  feet  above  sea,  until  they  rest  against  the  northernmost  spur  of 
Mount  Toby  on  the  west  and  extend  up  along  the  mountain  side  on  the 
east,  alDOve  the  notch  by  which  Locks  Brook  comes  out  of  the  mountains, 
and  a  remnant  still  runs  up  into  this  notch.  They  end  abruptly  along  a 
broad  curve  (b",  PI.  XXXV,  C),  concave  to  northward,  and  sink  down  by 
a  slope  as  steep  as  sand  will  take  to  the  level  of  the  high  terrace  (336  feet 
above  tide)  which  formed  the  shore  flats  of  the  Montague  Lake  (see  p.  615). 

It  seems  to  me  clear  that  the  ice  that  filled  the  Montague  basin  pressed 
into  the  north  end  of  the  Mount  Toby  Valley,  compelling  the  waters  of 
Locks  Brook  (or  Sawmill  Brook)  to  find  their  way  southwardly  down  this 
valley  and  clogging  the  northern  portion  of  the  valley  with  heavy  sands; 
and  so  far  south  as  the  kettle-holes  extend,  so  far  south  the  snout  of  the 
ice  was  projected  into  the  valley  and  heavily  covered  by  the  sands — the 
kettle-holes  beiiig  a  measure  of  the  portion  which  still  remained  unmelted 
beneath  the  sands  when  the  further  recession  of  the  ice  allowed  Locks 
Brook  to  run  directly  westward  into  the  Connecticut,  while  the  great  con- 
cave slope  which  bounds  these  sands  (b^^,  PI.  XXXV,  C)  on  the  north  marks 
tlie  shore  line  of  the  thicker  ice,  against  which  the  sands  were  piled. 

The  waters  running  southward  through  the  canyon  already  described 
cut  a  deep  and  narrow  channel  in  the  jointed  quartzite,  where  they  seem 
to  have  formed  rapids,  and  at  one  place  a  distinct  waterfall.  They  left  no 
deposits  in  this  narrow  part,  but  found  it  in  flood  time  an  insufficient  outlet 
and  turned  eastward  through  the  side  valley  into  the  Leverett  Lake,  clog- 
ging this  with  abundant  sands.  At  the  south  end  of  this  Mount  Toby 
canyon  there  remains  on  either  side  of  its  widened  mouth  a  delta  deposit 
of  rounded  bowlders,  6  to  8  inches  in  size,  from  which  all  finer  material  is 
removed,  as  a  witness  of  the  violence  of  the  current,  and  farther  south  the 
broad,  level  South  Leverett  plain  (1  s  h),  west  of  Leverett  railwaj^  station. 


586  GEOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 

gives  evidence  of  the  volume  of  the  sands  which  were  carried  through  this 
narrow  gorge  to  form  the  massive  delta  thrust  into  the  main  valley  which 
now  remains  as  a  most  important  portion  of  the  shore  bench  of  the  Con- 
necticut Lake  (see  p.  639). 

THE   LOCKS   POND   LAKE. 

Following  up  Locks  Brook  into  the  mountains,  we  find  high  sands 
bordering  it  with  every  widening  of  the  narrow  valley  at  all  levels  until 
we  reach  the  top  of  the  hills  and  come  upon  the  broad  basin  of  finely  sorted 
sands  surrounding  Locks  Pond.  These  I  have  already  connected  with  the 
line  of  sands  which  can  be  traced  southward  through  Pelham  to  Palmer. 
It  is  clear,  thus,  that  the  ice  retreated  down  this  valley,  but  that  its  shape 
did  not  favor  the  formation  of  extended  deposits,  and  its  position  as  a  deep 
transverse  gorge  extending  quite  across  the  block  of  hills  between  the  Con- 
necticut and  Swift  River  valleys  was  such  that  it  intercepted  all  southward 
currents  so  soon  as  it  was  free  from  ice,  and  it  is  curious  to  see  how  by 
de^dous  ways  it  deposited  its  burden,  now  in  the  Leverett  Lake,  now  in  the 
broad  delta  at  the  south  end  of  the  Mount  Toby  Valley,  now  clogging  up 
the  northern  end  of  the  latter,  while  at  the  last  it  has  contributed  very  little 
to  the  filling  up  of  the  Montague  basin,  into  which  it  now  enters  from  the 
mountains. 

Locks  Pond  now  lies  in  the  midst  of  a  broad  accumulation  of  fine 
sands  (1  p^)  which,  followed  eastward  by  the  road  to  the  Mineral  Springs 
House,  ends  abruptly  on  the  verge  of  the  steep  descent  to  the  Swift  River 
Valley,  and  this  seems  to  have  been  at  one  time  an  outlet  for  the  lake  and 
to  have  controlled  the  height  of  its  waters. 

NOTCHES  THROUGH  THE  HOLYOKE  RANGE  AND  THE  LAKE  NORTH  OF 

MOODY  CORNERS. 

The  manner  in  which  the  Belchertown  notch  was  occupied  by  the 
Pelham  River,  and  in  which,  by  the  expansion  of  this  river  into  the 
Dwight's  station  lake,  its  waters  came  to  occupy  also  the  next  pass  west — 
the  Bay  Road  Pass — is  detailed  in  the  section  on  p.  577.  These  events 
were  the  prelude  to  the  complete  occupancy  of  the  valley  by  the  lake 
waters,  but  at  earlier  times,  immediately  following  the  emergence  of  the 
range  from  the  ice,  the  passes  were  used  as  transient  watercourses,  though 
no  line  of  esker  ridges  extends  north  or  south  from  any  one  of  them. 


NOTCHES  THROUGH  THE  HOLYOKB  EANGE.  587 


THE   GRANBY   ROAD   LAKE. 

At  the  second  pass  west  of  the  Belchertown  ponds,  occupied  l)y  the 
little-used  road  from  Andierst  to  Granby,  there  expands  in  the  center  of  the 
pass  a  broad,  flat  plain  of  stratified  sands  (m  t)  at  a  level  of  410  feet  above 
sea.  The  western  half  is  well  preserved.  The  eastern  half  has  been  deeply 
notched  by  the  waters  of  a  spring-fed  brook  which  escape  toward  the 
north.  North  and  south  the  road  goes  down  over  till  to  the  lower  and 
later  sands,  but  toward  the  south  the  watercourse  by  which  the  ovei-flow 
passed  into  the  basin  to  the  south  is  well  marked  by  thin  layers  of  sand  and 
gravel. 

THE  NOTCH. 

In  the  middle  of  the  east-west  portion  of  the  range  a  pass  463  feet 
above  sea  level  has  traces  of  coarse-bedded  sands  in  its  bottom,  and  is  con- 
tinued south  in  a  deep  canyon  cut  in  the  sandstones  and  underlying  diabase, 
down  the  side  of  which  the  road  goes.  This  canyon  I  imagine  to  have 
been  cut  by  a  torrent  coming  off  the  ice  to  the  north  and  through  the 
notch,  or  at  least  to  have  been  occupied  and  enlarged  by  such  a  stream. 
(See  p.  510  and  PL  XI,  p.  610.) 

THE  LOW  PLACE  AND  MOODY  CORNERS  LAKE. 

Farther  west  and  just  east  of  the  Holyoke  House  is  another  pass,  which 
is,  however,  tmiied  east  by  the  great  mass  of  the  Black  Rocks  diabase, 
and  the  waters  coming  through  this  pass  in  the  same  way  seem  to  have 
supplied  the  sands  which  filled  up  a  small  lake  (m  t)  that  extended  east  and 
west  between  the  two  diabase  ridges  north  of  Moody  Corners.  This  lake 
stood  at  the  height  of  314  feet  and  drained  from  its  west  end  southwardly 
across  the  eastern  tongue  of  the  Black  Rock  dike  where  it  is  narrowest,  and 
it  was  filled  with  sands  to  great  depth,  the  earlier  sandstone  having  been 
very  deeply  scooped  out  here  by  the  ice. 

THE   HOLYOKE   NOTCH. 

The  same  flood  waters  continued  farther  west,  and  passed  at  this  high 
level  between  the  ice  and  Moimt  Holyoke  into  the  Springfield  Lake,  form- 
ing the  gorge  terrace  of  Dry  Brook  Hill  described  on  page  661. 


588  GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

THE  PELHAM  RIVER  AND  THE  "MORAINE  TERRACE"  SANDS  ALONG  THE 
EASTERN  VALLEY  SIDE,  JUST  ABOVE  THE  LEVEL  OF  THE  HIGH  TERRACE. 

The  continued  melting  of  the  ice  at  last  restricted  it  to  the  Connecticut 
Valley,  and  melting  back  from  the  steep  rim  of  the  valley  on  the  east  it 
formed  a  great  waterway  all  along  the  eastern  side  of  the  Amherst  basin, 
which  continued  south  through  the  Belchertown  notch  along  the  eastern 
edge  of  the  Springfield  basin.  In  it  was  deposited  a  great  body  of  sand  and 
gravel  (m  t),  occupying  the  position  of  a  lateral  moraine  of  the  Connecticut 
Valley  glacier,  but  ha^dng  rather  the  origin  and  structure  of  an  esker.-^  It 
was  a  great  temporary  river  bed,  its  eastern  bank  being  the  mountain  side, 
its  western  in  part  the  low  front  ranges  of  the  gneiss,  ridges  of  till,  and  the 
eastern  end  of  the  Holyoke  range,  but  for  the  most  part  the  eastern  rim  of 
the  great  ice  mass  which  still  filled  the  valley  and  formed  for  much  of  the 
way  the  bottom  as  well  as  the  western  bank  of  the  stream.  The  heavy 
sands  deposited  by  this  stream,  where  they  rested  upon  a  rock  bottom,  are 
still  flat-topped  and  rest  against  the  rock  on  the  east,  with  all  the  peculi- 
arities of  a  river-bottom  deposit,  at  a  height  of  50  to  60  feet  above  the 
highest  terrace  of  the  Connecticut  Lake  which  followed.  This  is  true  on 
the  West  Pelham  plain,  and  southward  along  the  eastern  part  of  the  deposit, 
while  its  western  portion  seems  to  have  rested  on  the  ice,  and  as  the  ice 
melted  this  was  dropped  to  lower  and  lower  levels,  its  bedding  being 
much  shifted  and  confused  by  the  process  until  it  came  to  rest  in  a  great 
series  of  kettle-holed  sands  stretching  down  to  and  below  the  level  of  the 
highest  normal  terrace  of  the  Connecticut.  This  latter  also  has  abundant 
kettle-holes,  from  which  I  conclude  that  the  deeply  buried  remnants  of 
the  ice  had  not  wholly  disappeared  when  the  great  lake  assumed  its  place 
and  entered  upon  its  work  of  carving  out  its  terrace  flat  in  these  kame 

deposits. 

The  normal  terrace  or  bench  of  the  Connecticut  Lake  is  determined  by 
its  agreement  in  level  with  the  highest  terrace  on  the  other  side  of  the  valley, 
where  great  deltas  of  the  finest  material,  most  delicately  stratified,  mark 
the  highest  level  of  the  waters,  and  where  on^  passes  from  these  directly 
onto  rock  or  till  without  crossing  the  complicated  series  of  bedded  deposits 
on  the  eastern  side  which  I  have  described. 


'It  is  tlie  "  moraine  terrace "  of  President  Hitchcock,  an  extremely  apiiosite  name,  showing  that 
he  had  very  clearly  grasped  the  peculiarities  of  its  formation.     Surface  Geology,  page  33,  1860. 


THE  PELHAM  lilVEK  SANDS.  589 

The  excavations  of  the  Central  Kaih-oad  on  either  side  of  Dwight's 
station  and  tlu-ough  tlie  Belchertowu  notch  gave  me  abundant  opportunity 
to  study  the  anatomy  of  these  sands,  and  especially  the  peculiarities  of  the 
kettle-holes,  and  this  material,  with  matter  derived  from  other  portions  of 
the  valley,  I  have  brought  together  in  Chapter  XIX,  page  665. 

I  have  given  the  same  color  to  all  the  kame-like  sands  (1)  which  stretch 
southward  at  the  foot  of  the  eastern  rim  of  the  valley  just  above  the  high- 
est normal  terrace,  (2)  which  extend  along  the  north  and  west  slope  of  the 
Holvoke  range,  and  (3)  which  rise  in  the  central  parts  of  the  valley 
above  the  level  of  the  terrace  flat.  The  first  and  most  interesting  series,  to 
which  I  have  given  for  convenience  of  reference  the  name  of  the  Pelham 
River,  from  the  place  where  its  remnants  are  best  preserved,  is  continuously 
traceable  from  North  Amherst  through  the  Belchertown  notch,  and  from  this 
point  great  disconnected  patches  of  entirely  similar  sands  and  gravels  occur 
at  the  foot  of  the  eastern  valley  rim  south  across  the  State ;  and  while  one 
can  not  assert  that  they  were  laid  down  exactly  contemporaneously  in  the 
bed  of  a  single  glacial  river,  the  fact  that  they  maintain  just  the  same  slope 
as  the  high  terrace  makes  that  the  most  simple  supposition.  At  all  events, 
their  common  origin — for  they  were  all  deposited  between  the  ice  and  the 
valley  rim — is  sufficiently  probable  to  justify  a  common  color  for  them  all. 

The  deposits  of  the  Pelham  River  begin  just  south  of  North  Amherst 
and  swing  round  east  with  the  curvature  of  the  rocky  slope  to  the  point 
where  the  stream  received  the  waters  of  the  Leverett  Lake  (p.  584).  The 
Pelham  Lake  drained  into  this  stream,  breaching  the  last  great  terrace 
which  had  stretched  across  the  mouth  of  the  basin,  and  the  stream  itself 
wore  deeply  eastward  into  the  soft  material  of  this  terrace,  forming  the 
flat  on  which  the  Orient  House  stood  (fig.  32,  p.  578),  and  ran  south  from 
here,  bounded  for  a  long  way  on  the  west  by  the  gneiss  ridge  which 
extends  south  from  the  west  village  of  Pelham,  and  washed  the  side  of 
the  mountain  on  the  east  to  a  height  of  400  feet.  It  is  a  perfect  water 
course,  which  farther  south  lacks  a  western  boundary,  it  having  here  rested 
against  the  ice  (b^°,  PI.  XXXV,  C,  D),  and  where  it  passes  into  Belchertown 
a  massive  di-umlin  forms  its  western  rim,  and  it  now  ends  in  a  great  delta 
thrust  out  into  the  depression  in  which  Dwight's  station  lies.  As  one  stands 
on  the  eastern  end  of  the  Holyoke  range  and  looks  north,  one  sees  this  delta 
.  resting  against  the  mountain  on  the  east  and  against  the  low  dam  of  the 


590  GEOLOGY  OF  OLD  HAMPSHIRE  COUi^TY,  MASS. 

drift  hill  on  the  west,  while  at  a  much  lower  level  the  high  terrace  of  the 
Connecticut  Lake  swings  round  the  drift  hill  on  the  west  and  south.  This 
was  the  last  chapter  in  the  history  of  the  stream.  This  delta  was  caused 
by  a  breaching  of  the  stream  at  this  point  by  the  melting  back  of  the  ice  to 
leave  a  small  temporary  lake  in  its  course,  in  the  angle  in  which  Dwight's 
station  now  lies,  for  the  stream  during  its  earlier  stage  seems  to  have  flowed 
aci'oss  this  depression  upon  the  surface  of  the  ice,  and  its  heavy  sands  are 
continuous  at  the  pro2Der  level  along  the  flank  of  the  Pelham  Hills  east  of 
Dwight's  station,  across  from  the  delta  to  the  sands  of  the  Belchertown  Pass, 
and  a  section  of  them  is  figured  and  described  in  the  section  on  kettle-holes 
(p.  665).  Through  the  Belchertown  Pass  it  threw  down  the  abundant 
sands  and  gravels  which  stretch  from  wall  to  wall  of  the  pass  and  extend 
through  its  entire  length.  Their  greatest  height  is  337  feet,  though  many 
kettle-holes,  some  of  the  largest  size,  disguise  the  original  level  of  the 
sands.     The  three  Belchertown  ponds  occupy  three  of  these  depressions. 

The  railroad  cuttings  showed  most  confused  and  tortuous  stratification, 
abrupt  alternation  from  fine  sand  in  great  mass  to  the  coarsest  gravel,  great 
bodies  of  fine  sand  standing  with  the  bedding  almost  vertical,  as  if  they  had 
been  undei-mined  when  frozen,  and  kettle-holes,  some  partly  and  some 
wholly  filled  up  by  later  sands,  as  if  the  ice  beneath  had  melted  away  while 
the  floods  were  still  in  progress. 

We  may  at  this  point  imagine,  for  the  sake  of  clearness,  the  following 
stages  in  the  retreat  of  the  ice  from  the  Springfield  Lake  basin,  or  the 
Granby  basin,  which  is  a  part  of  the  former,  premising  that  the  ice  would 
disappear  south  of  the  mountain  much  earlier  than  north:  (1)  When  the 
ice  had  only  melted  away  from  the  eastern  rim,  so  as  to  make  a  waterway 
continuous  south  from  the  Belchertown  notch  along  the  foot  of  the 
eastern  valley  rim;  (2)  when  the  ice  had  melted  away  from  the  south  face 
of  the  Holyoke  range ;  (3)  when  the  ice  had  melted  back  from  the  north 
face  of  the  same  range  for  a  small  distance.  We  imagine  the  ice  to  still  fill 
the  whole  valley  of  the  Connecticut  and  to  prevail  over  the  western  hills, 
but  to  have  disappeared  from  the  eastern. 

1.  In  the  first  case  the  waters  passing  through  the  Belchertown  notch 
would  have  continued  southward,  and  we  find,  after  a  brief  interruption, 
coarse  kettle-holed  sands,  which  commence  at  P.  Chandler's,  opposite  the 
lower  pond,  at  326  feet  above  sea,  and  are  quite  continuous  across  Granby, 


THE  PELHAM  EIVER  SANDS.  591 

often  developed  as  liiu-s  of  kaiue  ridges  or  as  reticulated  ridges,  in  part 
bounded  on  tlie  west  by  a  line  of  drumlins,  as  opposite  the  Belchertown 
poorhouse,  in  part  sloping  down  directl}'  to  the  high  lake  ten-ace. 

( )n  passing  the  north  line  of  Ludlow  a  great  area  of  till,  leaning  on  the 
hi"-h  rock  border  on  the  east,  projects  west  across  the  path  of  the  water- 
course we  are  following.  Across  this  area  there  is  a  channel  of  proper  height 
to  have  been  the  continuation  of  the  same,  but  I  foinid  here  only  indistinct 
traces  of  water  action.  South  of  this,  however,  before  one  reaches  the  vil- 
laoe  of  Ludlow,  is  a  broad  area,  which  extends  southward  beneath  the  village 
and  to  the  Chicopee  River,  of  tlie  same  high  sands,  which  have  come  for  the 
most  part  down  Broad  Brook,  and  partly  also  down  the  Chicopee  River  from 
the  Belchertown  Lake.  The  same  sands  appear  south  of  the  Chicopee  and 
extend  in  less  amount  across  Wilbraham. 

2.  With  the  melting  back  of  the  ice  from  the  southern  slope  of  the 
Holyoke  range  the  waters  passing  through  the  Belchertown  notch  Avould 
be  deflected  westward  and  southwestward,  along  the  south  foot  of  the  range, 
to  fill  up  the  deeply  eroded  area  that  extends  past  Moody  Corners  clear 
to  the  Connecticut,  which  has  since  been  partly  reexcavated  by  Bachelors 
and  Elmers  brooks;  and  as  the  ice  retreated  still  more  the  waters  would 
carry  their  load  of  sand  and  gravel  directly  into  the  wide  Granby  basin  to 
build  up  the  broad  plain  surrounding  Forge  Pond.  The  present  condition 
of  the  gravels  extending  south  from  the  notch  makes  it  certain  that  this  was 
the  last  course  of  the  waters.  The  coarse  gravels  extending  through  the 
notch  where  they  surround  the  third  pond  are  still  very  coarse,  pebbles  6 
inches  in  diameter  being  abundant.  Here  the  gorge  expands  and  the 
gravels  extend  across  the  widening  basin,  growing  gradually  finer.  Halfway 
to  the  east  line  of  the  town  (Granby)  they  are  4-mch  gravels;  at  the  town 
line,  2-incli  gravels;  where  the  wood  road  cuts  deeply  into  them  north  of 
Moody  Corners  and  in  South  Hadley  they  are  exposed  for  35  feet  as  fine, 
well-bedded  sands. 

3.  By  the  melting  back  of  the  ice  from  the  north  side  of  the  Holyoke 
range  the  river  expanded  lake-like  along  its  northern  foot  and,  aided  by 
waters  coming  directly  across  the  ice,  a  great  body  of  sand  was  rapidly 
carried  in  here.  This  extends  west  just  beyond  the  "notch  road"  to  South 
Hadley  and  stretches  through  the  much  lower  notch  near  the  east  end  of 
the  range,  and  is  continuous  with  the  sands  in  the  Belchertown  notch. 


592  GEOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 

4.  Finally  the  waters  expanded  so  considerably  that  the  Pelham  River 
emptied  into  the  lake  thus  formed,  building  the  delta  already  described 
above  Dwight's  station,  and  soon  disappearing. 

THE  SUNNY  VALLEY  LAKE. 

The  only  other  large  accumulation  of  glacial  sands  on  the  eastern  side 
of  the  river  occupied  the  Sunny  Valley  in  the  northern  part  of  Warwick, 
and  extended  across  into  Winchester,  New  Hampshire,  and  was  drained  by 
the  Valley  Brook  into  the  Perchee  Brook  and  thus  into  the  Connecticut. 
This  lies  for  the  most  part  outside  the  limits  set  in  this  work. 

THE     SANDS    ALONG    THE    WEST     SIDE     OP    THE    MOUNT    TOM    RANGE   AND   IN   THE 
WESTPIELD   BASIN   ABOVE   THE   LEVEL   OF   THE   HIGH   TERRACE. 

The  sands  which  rest  against  the  northern  slope  of  the  Holyoke  range 
extend  west  to  a  point  a  little  beyond  the  notch  road,  and  are  conspicuously 
absent  from  the  rest  of  the  north  face  of  the  range  farther  west.  This  may 
indicate  the  distance  west  to  which  the  waters  penetrated  from  the  Dwight's 
station  lake,  or  enlargement  of  the  Pelham  River  (see  p.  589),  or  these 
sands  may  have  extended  farther  west  and  have  been  swept  away  by  the 
later  lake  waters.  Sands  at  the  same  level  above  the  high  terrace  begin 
again  on  the  west  side  of  the  river,  just  east  of  the  old  road  to  the  Nonotuck 
Mountain  House,  and  extend  thence  along  the  whole  face  of  the  Mount 
Tom  range  in  Northampton  and  Easthampton,  in  a  great  mass  of  ridgy 
sands  and  gravels,  in  which  the  high  terrace  flat  of  the  lake  is  cut.  Similar 
sands  at  the  same  level  also  cover  White  Loaf,  in  Southampton,  and  the 
ridge  east,  which  rise  as  islands  in  the  broad  sand  flats  of  the  Hampden 
plains.  They  are  not  given  on  the  map.  They  had  clearly  a  common 
origin,  having  been  swept  in  between  the  mouiitain  and  the  ice,  or  off  the 
ice  onto  these  islands  after  the  ice  had  uncovered  them,  and  they  stood  out 
like  nunataks  above  it.  They  have  served  a  common  purpose  in  the  later 
economy  of  the  valley,  as  they  furnished,  I  have  no  doubt,  a  large  portion 
of  the  material  carried  south  by  the  two  channels  on  either  side  of  White 
Loaf,  and  spread  as  coarse  gi-avels  around  Hampden  ponds,  which  dwindle 
farther  south  in  the  broad  plain  to  the  fine  sands  of  "Poverty  Plain,"  here, 
of  course,  reenforced  by  the  abundant  contributions  of  the  Westfield  rivers. 


OHAPTEE    XVIII. 

THE  CHAMPLAIN  PERIOD  (Continued). 

OIjACIAIj  LAICES  west  of  the  CONNECTICUT  RIVEB. 

THE  GRANVILLE  LAKE. 

As  the  ice  retreated  northwesterly,  still  sending  great  lobes  down  the 
Connecticut  and  down  the  Westfield  River,  it  abandoned  the  high  valley 
which  occupies  the  whole  middle  of  the  town  of  Gi-anville,  while  its  Con- 
necticut lobe  still  closed  the  outlet  of  this  valley  at  the  northeast  corner  of 
the  town  and  the  gap  of  Munns  Brook,  which  is  cut  so  curiously  through 
the  middle  of  the  eastern  rim  of  the  valley.  This  rim  is  caused  by  the 
greater  durability  of  the  vertical  schists  of  which  it  is  made,  which  strike 
north  and  south  and  form  an  impassable  barrier  along  the  whole  eastern 
side  of  the  town,  except  that  it  is  cut  asunder  by  this  deep  notch  in  its 
middle,  down  which  a  road  once  ran. 

This  broad  valley,  which  extends  across  the  whole  length  of  the  town 
and  a  long  way  into  Connecticut,  was  filled  by  a  great  body  of  sands,  now 
finely  terraced  down  by  brooks  which  i-un  out  of  the  basin  on  the  north, 
east,  and  south  (g  P,  PL  XXXV,  B).  Its  height  is  plainly  deteiTuined  by 
its  southern  outlet,  where  the  brook  has  a  rocky  bottom,  and  it  is  clear  that 
when  the  sands  filled  the  basin  the  northeast  and  the  east  outlets  (b^)  must 
have  been  closed,  since,  on  being  opened,  the  brooks  which  occupy  them 
cut  down  deeply  through  the  sands  before  they  reached  the  rocky  bottom 
of  these  outlets,  proving  that  the  latter  were  preexistent  and  deep  enough 
to  have  kept  the  waters  at  a  much  lower  level  if  they  had  been  open. 

THE  NORTH  GRANVILLE  LAKE. 

Another  lake  of  great  extent  stretches  from  Granville  into  Blandford, 
suiTOunding  Cobble  Mountain  (g  P).  Its  coarse  sands  reach  a  gi-eat 
depth.     It  was  drained  by  the  setting  free  of  the  South  Branch  of  the 

MON  XXIX 38  593 


594  GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

"Westfield  River  tlirougli  the  wildest  gorge  in  Massachusetts,  deeply  rock 
cut,  and  abounding  in  very  large  potholes.  One  is  inclined  to  surmise  that 
some  portion  of  this  erosion  may  date  from  Glacial  or  eai'ly  post-Glacial 
time. 

THE  WESTHAMPTON  LAKE. 

A  much  more  extensive  and  interesting  lake  than  the  one  mentioned 
in  the  last  paragraph  occupied,  at  a  much  lower  level,  all  the  eastern  part  of 
Westhampton,  about  the  headwaters  of  the  Manhan  River  (g  P,  PL  XXXV,  B). 
It  wound  sinuously  among  great  islands  of  granite,  and  extended  south  into 
Easthampton,  where  it  passed  over  a  rocky  sluiceway,  which  fixed  its  level, 
into  the  headwaters  of  the  South  Branch  of  the  Manlian.  From  Loudville 
south  into  Southampton,  around  the  east  flank  of  Great  Mountain,  the  sands 
of  this  lake  extend  out  freely  into  the  Connecticut  Valley,  without  rocky 
support  on  the  east,  and  end  in  a  terrace  scarp,  below  which  a  broad  slope 
of  till  extends  down  170  feet  to  the  normal  high  ten-ace  of  the  Connecticut 
Lake.  It  is  plain  that  the  ice  of  the  Connecticut  River  glacier  furnished 
the  bank  of  the  lake  within  these  limits  (b®).  This  was  at  its  greatest 
size.  Subsequently  it  seems  to  have  persisted,  with  diminished  boundaries, 
and  to  have  received  the  overflow  from  the  Williamsburg  Lake,  farther 
north,  when  the  ice  had  retreated  north  so  as  to  set  this  free,  and  so  to  have 
for  a  long  time  I'etained  connection  with  a  long  and  complicated  series  of 
watercourses,  which  extended  back  north  to  the  valley  of  the  Deei'field  River, 
and  ceased  to  be  occupied  when  this  valley  was  abandoned  by  the  ice. 

So  soon,  however,  as  the  ice  set  free  the  gorge  at  Loudville  the  lake 
was  tapped  in  its  upper  portion,  and  the  greater  part  of  its  area  is  now  drained 
through  this  channel.  Two  watersheds,  however,  developed  in  this  area, 
one  at  the  south,  setting  off  a  portion  to  be  drained  by  the  South  Branch  of 
the  Manhan,  and  another  at  the  north,  which  drains  through  the  Roberts 
Meadow  Brook  into  the  Mill  River.  These  streams,  especially  the  middle 
ones,  have  cut  a  fine  set  of  upland  tei-races  in  the  sands  of  the  ancient  lake, 
and  as  one  sees  these  brooks  leave  their  upland  meadows  and  plunge  into 
deep  gorges  on  their  way  to  the  valley  below,  one  is  inclined  to  ask  how  far 
these  gorges  were  preexistent  and  how  far  they  have  been  cut  by  the  streams 
since  the  time  of  the  lake.  In  some  cases  the  disappearance  of  the  lake  may 
have  been  due  to  such  a  cutting  down  rather  than  to  the  removal  of  an  ice 
barrier  or  the  sudden  sealing  up  of  the  sources  of  the  glacial  waters.     I  have 


THE  AVILLiIAMSBURG  LAKE.  595 

for  the  most  pai-t  used  the  latter  as  a  working-  hypothesis.  In  several 
places,  as  in  the  Counecticut  gorge  above  the  mouth  of  Millers  River,  much 
erosiou  of  the  rocks  has  taken  place  since  the  time  of  the  lakes. 

THE    WILLIAMSBURG  LAKE. 

The  Mill  River  at  Williamsburg  village  has  cut  its  terraces  in  a  great 
body  of  coarse  sand,  whose  flat  surface  is  33  feet  above  the  stream.  TTntil 
the  ice  had  so  far  melted  back  that  the  Deerfield  River  was  open,  the  over- 
flow of  the  Ashfield  and  Conway  lakes,  described  below,  reached  this  lake 
by  way  of  Mill  River  and  Joe  Wright's  brook,  respectively,  though,  as  the 
waters  left  in  their  passage  through  these  narrow  gorges  no  deposits  to  attest 
their  former  presence,  there  is  on  the  map  an  apparent  break  in  the  conti- 
nuity of  the  deposits  between  them,  of  considerable  extent  in  the  case  of  Mill 
River.  The  proof  of  this  former  continuity  is  given  in  the  description  of 
the  other  lakes. 

The  sands  of  this  lake  (g  l\  PL  XXXV ,  A)  can  be  followed  down  South 
street  to  the  south  line  of  the  town,  where  they  divide,  one  band  going 
south  to  join  the  Westhampton  Lake,  the  other  southeast  in  Northampton  to 
where  it  widened  into  the  Roberts  Meadow  Lake,  whose  waters  regained  the 
valley  of  the  Mill  River  at  Leeds,  and  also  passed  south  into  the  valley  of 
the  Connecticut,  down  the  deep,  empty  gorge  west  of  Roberts  Hills.  This 
gorge  has,  as  in  so  many  other  cases,  a  brook  heading  in  its  bottom  and 
running  north,  and  another  brook  heading  farther  south  and  running  south, 
while  the  gorge  is  continuous  and  of  uniform  size  and  depth  from  the 
Roberts  Meadow  basin  to  the  open  Connecticut  Valley.  It  seems  to  me  a 
product  of  subglacial  drainage  or  of  the  obstructed  post-Grlacial  drainage  I 
am  here  tracing. 

THE  BEAVER  BROOK  LAKE  ABOVE  LEEDS. 

This  small  lake  lay  encircled  by  high  hills  in  the  east  part  of  Williams- 
burg and  was  drained  by  a  deep  gorge  through  which  the  brook  above 
named  now  flows  to  join  the  Mill  River  at  Leeds. 

THE  DEERFIELD  RIVER  LAKES. 

The  obstructed  drainage  south  of  the  Deerfield  River  (PI.  XXXV,  A) 
was  most  curious  and  complex.  That  it  was,  mutatis  mutandis,  the  counter- 
part of  the  drainage  south  from  the  Millers  River  (p.  573)  comes  out  very 
clearly.     The  ice  melted  back  across  the  high,  irregular  area  south  of  the 


596  GEOLOGY  OP  OLD  HAMPSHIEB  COUISTY,  MASS. 

river  with  a  front  rudely  east  and  west,  or  a  little  north  of  east  and  south 
of  west,  and  the  deep  transverse  valley  of  the  river  runs  northwest,  while 
deep  longitudinal  valleys  extend  south  from  it.  The  ice  thus  set  free  the 
lower  portions  of  the  Deerfield  Valley  first,  but  the  Connecticut  River  gla- 
cier dammed  its  mouth  for  a  long  time,  thus  turning  the  waters  south  across 
Conway  to  form  the  Conway  Lake,  south  of  Bardwells  Ferry,  whose  waters 
escaped  south  across  Hampshire  County  to  enter  the  valley  of  the  Con- 
necticut by  way  of  the  southward  ramifications  of  the  Williamsburg  Lake. 

At  the  same  time  the  ice  had  set  free  the  Deerfield  up  nearly  to  the 
mouth  of  Bear  River  in  Conway,  and  still  sent  a  lobe  up  this  valley  for  some 
distance,  from  the  south  end  of  which  the  waters  escaped  that  formed  the 
broad  Bear  River  Lake,  seen  in  the  middle  of  PI.  XXXV,  A,  which  drained 
into  the  Ashfield  Lake.  This  latter  was  supplied  by  a  lobe  of  the  glacier 
which,  west  of  Shelbiu-ne  Falls,  followed  up  Clessons  Brook  to  beyond 
Buckland  Center  (b").  This  lake  drained  east  into  the  Conway  Lake  arid 
sovith  by  way  of  the  headwaters  of  the  Mill  River  into  the  Williamsburg 
Lake.  Still  farther  west  the  waters  gathering  from  the  ice  which  fill  ed  the 
Deerfield  Valley  below  escaped  sotitheastwardly  from  the  extreme  north- 
eastern corner  of  Hawley  and  followed  Clessons  Brook  down  as  the  preced- 
ing current  followed  it  ujd,  and  the  two  currents  met  at  the  sharp  bend  of 
the  stream  at  Buckland  Four  Comers  and  joined  to  form  the  Ashfield  Lake 
mentioned  above.  Another  current  from  the  ice  going  south  up  the  valley 
of  Chickley  River  formed  the  lake  which  occupied  the  middle  of  Hawley. 
For  this  lake  I  could  discover  no  southward  outlet,  but  no  doubt  one  existed. 

Three  points  will  be  noticed  in  regard  to  this  drainage  :  (1)  The  waters 
moved  up  old  valleys  and  filled  them  to  a  level  determined  by  passes  far 
to  the  south,  over  which  the  waters  continued  into  another  drainage  basin ; 
(2)  after  the  retreat  of  the  ice,  brooks  heading  up  near  these  divides  ran 
north,  carrying  back  north  a  good  portion  of  the  gravels  which  had  been 
cai'ried  south ;  (3)  it  is  only  near  the  mouth  of  the  Deerfield  River  that  the 
deposits  of  these  lakes  extend  north  to  the  river  itself;  farther  west  they 
begin  some  distance  south  and  the  valleys  between  their  beginnings  and 
the  river  are  empty  and  bowlder  strewn,  while  on  the  east  side  of  the  Con- 
necticut the  opposite  order  holds,  viz:  at  the  head  of  Millers  River  the 
corresponding  deposits  extend  up  to  the  river  and  beyond  it  to  the  north, 
in  its  middle  course  up  to  the  river  and  in  its  lower  parts  not  quite  up  to 


DEKKFIELD  RIVEK  AND  TEIBUTAKIES.  597 

the  stream.  In  the  tollowiiig-  more  minute  description  of  these  lakes  more 
stress  is  hiid  upon  the  shiftiugs  of  the  ice  front  during  the  formation  of  each 
hike  and  on  the  character  of  its  deposits. 

THE  DEERFIELD  RIVER  AND  ITS  TRIBUTARIES  ON  THE  NORTH. 

This  stream  hes  so  nearly  in  tlie  direction  of  the  melting  of  the  ice 
that  it  was  a  main  channel  for  the  exit  of  its  waters,  and  was  not  itself 
encumbered,  except  that  once  the  readvance  of  the  ice  in  the  Connecticut 
Valley  threw  a  dam  across  its  mouth.  The  same  is  true  in  the  main  of  its 
northern  branches. 

The  deep,  tortuous,  and  most  picturesque  valley  of  the  Deerfield 
widens  slightly  in  Cliarlemont  and  Shelburne,  and  here  a  considerable  body 
of  sand  was  gathered,  and  in  several  places  pretty  series  of  intermediate 
teiTaces  have  been  cut  in  this  deposit  of  the  flood  period  and  above  the 
present  flood  plain  of  the  river.  Exactly  as  in  Russell  the  Westfield  River 
encircled  a  great  hill  in  midstream,  so  the  flooded  Deerfield  surrounded  a 
great  hill  in  Shelburne,  and  the  railroad  makes  a  short  cut  through  the 
abandoned  waterway. 

Below  Shelburne  Falls  the  river  runs  in  a  deep  canyon  till  it  reaches 
the  Connecticut,  and  it  is  hard  to  say  whether  the  great  height  of  the 
Chaiiemont-Shelburne  beds  is  due  entirely  to  the  setting  back  of  the  waters 
above  this  deep,  narrow  gorge  or  partly  to  possible  ice  dams.  In  all  this 
distance  there  are  only  traces  of  terraces  referable  to  the  flood  period  or  to 
any  subsequent  time,  but  the  stream  runs  deep  in  a  rocky  gorge. 

It  is  characteristic  also  of  the  streams  that  enter  the  Deei-field  from  the 
north  that  either  they  were  open  waterways  during  the  melting  of  the  ice — 
and  they  are  therefore  now  deeply  sunk  in  empty  valleys  with  traces  of 
their  high  flood  terraces  in  coarse  gravel  beds  left  as  remnants  in  sheltered 
places  and  with  narrow  and  interrupted  flood  plains — or  they  seem  to  have 
been  occupied  by  the  ice  during  the  height  of  the  flood,  at  least  in  their 
upper  reaches,  and  so  are  wholly  empty  of  anything  except  till  above  the 
low  level  of  recent  flooding.  This  seems  to  have  been  the  case  with  the 
Deerfield  itself  above  the  tunnel  entrance,  and  fine  terminal  moraines  (1  m) 
have  been  thrown  across  the  stream  at  several  places  during  the  recession 
of  this  last  lobe  of  the  ice. 

The  curious  "delta  terraces"  which  appear  where  the  tributaries  on  the 
north  side  meet  the  main  stream  are  discussed  elsewhere  (see  p.  605). 


598  GEOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 

The  ti'ibutaries  on  the  south  side  have  for  the  most  part  cut  their  way- 
through  heavy  glacial  lake  deposits,  and  their  facies  is  thus  extremely  dif- 
ferent from  the  north-side  tiibutaries,  as  the  former  are  bordered  in  their 
upper  courses  by  broad,  heavy  deposits  of  high-level  sands  and  gravels  in 
which  they  have  cut  their  teiTaces,  while  on  the  north  the  streams  come 
down  in  narrow  gorges,  and  only  in  Coleraine  does  one  widen  to  form  any 
considerable  meadow.  This  in  part  explains  why  Conway  and  Ashfield 
are  more  flourishing  villages  than  the  northern  tier  of  towns  from  Leyden 
to  Monroe. 

THE  CONWAY  LAKE. 

Just  at  the  Conway  station  the  train  crosses  at  a  dizzy  height  the  South 
River  where  it  enters  the  Deerfield.  The  station  is  about  at  the  level  at 
which  the  waters  stood  at  their  highest  flood  after  they  had  obtained  free  pas- 
sage to  the  Connecticut.  The  Deerfield  now  runs  in  its  rocky  bed  nearly  200 
feet  below,  and  the  road  from  the  station  toils  iip  over  heavy  sands  another 
hundred  feet  to  a  broad,  level  area  of  sand,  bounded  on  the  south,  east,  and 
north  by  the  South  and  Deerfield  rivers,  which,  when  the  ice  obstruction 
(b^^,  PI.  XXXV,  A)  below  was  removed,  cut  down  through  these  sands  into 
the  rock  so  quickly  that  they  did  not  wear  back  at  all  into  the  sands.  A 
great  triangle  between  the  rivers,  bounded  on  the  west  by  the  road  from  the 
South  River  to  the  Deerfield,  and  a  mile  on  a  side,  is  occupied  by  this  great 
body  of  sands  (g  P) ;  in  its  eastern  and  larger  part  it  is  quite  horizontal,  at 
about  460  feet  above  sea,  while  in  its  western  part  the  sand  rises  nearly  100 
feet  higher  and  is  covered  by  till,  as  if,  at  an  earlier  stage  of  the  lake,  the 
waters  had  stood  above  this  higher  level  and  brought  up  the  sands  to  that 
level,  and  then  oscillations  of  the  ice  brought  in  a  covering  of  till  over  part 
of  the  area  and  determined  then  or  later  a  lower  level  for  the  lake,  down  to 
which  its  sands  were  terraced.  The  area  requires  more  study  than  I  could 
give  it.  The  sands  at  this  lower  level  are  continuous  as  a  broad  band  south, 
up  the  valley  of  the  South  River,  widening  over  the  area  of  the  village  of 
Conway  and  receiving  there  a  body  of  sands  which  extend  up  the  South 
River  through  Burkville,  in  that  part  of  its  valley  which  runs  northwest. 

The  South  River  enters  the  town  running  east,  and  holds  this  direc- 
tion a  mile  (the  latter  part  is  an  empty  valley);  then  it  bends  south  a 
mile  to  Conway,  and  in  this  part  it  was  occupied  by  a  glacial  current  which 
moved  south  to  meet  at  Conway  village  the  current  moving  south  up  the 


THE  CONWAY  LAKE.  599 

valley  of  South  River  from  the  station.  It  seems  to  me  probable  that  when 
the  ice  fii'st  melted  nut  of  the  great  triangle  at  the  station  it  still  filled  the 
deej)  valley  at  and  north  of  Conway  village,  while  the  Connecticut  glacier 
danuned  up  the  mouth  of  the  Deei-field  and  held  the  waters  up  to  a  height  of 
])('rhaps  550  feet.  After  this  the  ice  abandoned  the  South  River  Valley  as 
far  \\-est  as  the  first  bend  in  the  river  mentioned,  above  a  mile  from  the  west 
line  of  the  town.  Then  the  waters,  passing  down  the  two  lobes  of  this  val- 
h'A-  and  joining  where  the  village  now  is,  filled  the  valley  to  the  height  of 
the  ground  where  the  academy  stands,  and  all  the  area  to  the  south  (now 
reemptied  by  erosion),  and  escaped  southwardly  by  the  narrow  pass  by 
which  the  main  road  goes  south  into  Whately.  As  one  goes  south  from 
Conway  he  sees  the  broad,  level  gravel  plains,  100  feet  above  the  village, 
which  surround  the  town  and  extend  south,  passing  continuously  and  at  the 
same  level  into  the  fiat,  plainly  waterworn  bottom  of  the  narrow  canyon, 
and  it  is  clear  that  this  canyon  has  fixed  the  level  of  the  lake.  We  follow 
this  watercourse  southward  easily  and  find  it  expanding  into  a  lake  around 
the  headwaters  of  Roaring  Brook,  and  branching  to  follow  this  valley 
down  a  mile  southeast,  ending  abru^Dtly.  The  Connecticut  glacier  would 
seem  to  have  still  clogged  this  valley,  and  I  have  so  represented  it  (b^^,  PI. 
XXXV,  A).  The  main  stream  channel  continues  south  into  Whately  and, 
reaching  the  headwaters  of  West  Brook,  widens  considerably  and  then  con- 
tracts at  West  Whately,  where  it  bends  sharply  west  into  Williamsburg.  It 
is  quite  remarkable  that  it  should  thus  bend,  for  the  open  West  Brook  Val- 
ley turns  here  toward  the  east,  and,  after  50  rods  of  empty  valley  way, 
expands  on  either  side  of  the  brook's  bed ;  and  200  feet  below  the  sands  of 
the  above  watercourse  a  great  area  of  heavy  sorted  gravels  begins,  which 
continues  southeast  with  the  brook  for  a  mile,  widening  to  above  a  half 
mile  and  ending  abruptly  with  a  great  scarp  which  overlooks  a  broad,  sand- 
less  valley.  Remnants  of  ice  on  the  east  of  the  main-valley  watercourse 
must  have  kept  it  out  of  the  Roaring  Brook  Valley,  as  above,  and  also 
deflected  it  at  West  Whately  (b^^),  and  the  ice,  being  breached,  let  the 
waters  tlirough  in  a  flood,  which  dropped  this  great  volume  of  gravel  as 
it  expanded  into  the  open  valley  after  the  manner  discussed  under  the 
section  concerning  high-level  deltas  (p.  605),  or  the  ice  may  have  erected 
a  later  barrier  lower  down  the  valley  (b^").  In  Williamsburg  the  stream 
expanded  into  another  basin,  now  a  broad  sand  plain,  and  escaped  south 


600  GEOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 

through  a  curious  narrow  canyon,  in  the  bottom  of  which  Wright's  brook 
now  rises  from  a  large  spring.  Down  the  course  of  this  brook  the  waters 
passed  to  join  those  of  the  Williamsburg  Lake. 

THE  BEAR  RIVER  LAKE. 

The  fullness  with  which  all  the  evidence  concerning  the  formation  of 
the  deposits  in  this  Ijasin  can  be  traced  leaves  little  to  be  desired.  The 
basin  is  a  broad  one,  extending,  with  its  greatest  dimension  east  and  west, 
across  the  line  between  Ashfield  and  Conway  (middle  of  PI.  XXXV,  A). 
It  is  surrounded  on  all  sides  by  high  ground,  except  a  narrow  passage  at 
the  northeast  corner,  and  sends  tlu-ee  great  lobes  northward  among  the  hills. 
In  its  southern  part  it  is  filled  to  a  great  height  by  an  enormous  volume  of 
coarse  sand,  especially  in  the  area  around  the  cemetery  at  School  No.  2. 
The  height  to  which  these  sands  were  brought  up  was  determined  by  the 
height  of  the  col  at  the  southwest  portion  of  the  basin  by  which  the  waters 
escaped  into  the  Ashfield  Lake  along  the  road  which  runs  south  to  Ashfield 
Plains.  These  sands  were  brought  in  while  the  ice  was  retreating  from  the 
valley  and  still  filled  its  northern  parts,  as  in  all  the  northern  portions  of  the 
basin  the  sands  occupy  a  lower  level,  and  it  is  plain  that  they  were  never 
heaped  up  to  the  height  of  the  south-side  sands  and  then  eroded.  It  is  there- 
fore probable  that  the  north  side  of  the  basin  was  still  filled  with  ice  when 
the  latter  were  brought  in,  as  they  must  have  come  from  the  north. 

When  the  ice  had  completely  left  this  basin  it  marked  its  next  halting 
place  with  beautiful  clearness.  The  water  maintained  its  former  level  after 
this  retreat,  this  being  conditioned  by  the  col  in  the  southwest  corner.  It 
carved  a  broad  bench  in  the  till  around  the  north  border  of  the  lake  and 
brought  in  great  bodies  of  sand  over  its  bottom,  but  not  enough  to  fill  it. 
If  these  sands  are  followed  to  the  northeast  corner  of  the  basin,  they  are 
found  to  extend  a  distance  along  a  narrow  rock-bottomed  valley,  scarcely 
covering  the  rocky  floor.  The  rock  bottom  of  the  valley  then  sinks  rap- 
idly, while  the  sands  widen  somewhat  and  continue  at  the  old  level,  thus 
filling  the  deepened  valley  with  beds  of  very  great  thickness.  At  a  cer- 
tain point  in  this  valley  they  end  abruptly  (b"),  and  one  goes  down  by 
a  great  lobed  scarp  to  the  deep  valley  bottom,  and  for  100  rods  down- 
stream (northwardly)  the  steep  valley  sides  are  strewn  with  glacial  bowlders 
to  the  water's  edge.     These  sands  are  grooved  in  the  middle  by  the  Bear 


THE  ASHFIELD  LAKE.  601 

River,  \\liicli  li;is  cut  ;i  (leep  passageway  througli  them.  The  small  river 
o-oes  (111  Inr  ;i  mile  nortli  in  a  deep,  sandless,  l^owlder-strewn  valley  to  join 
tlie  Di'frlicld. 

It  is  plain  tliat  the  ice  dammed  this  valley  and  that  the  sands  were 
hoai)ed  up  against  it,  and  that  it  then  retreated  and  left  the  sands  to  cave 
into  the  o-reat  northward-facing  scarp  after  the  changes  in  the  ice  farther 
up  the  Ueertield  Kiver  had  opened  up  other  channels  of  escape  for  the 
waters. 

THE  ASHFIELD  LAKE. 

The  gi-eat  bodies  of  flat  sands  in  the  middle  of  Ashfield  (middle  of  PL 
XXXV,  A)  have  naturally,  in  this  extremely  hilly  country,  given  the  vil- 
lage the  name  of  Ashfield  Plains.  The  Ashfield  Lake  is  represented  by  a 
peculiar  body  of  sand  surrounding  a  great  rocky  hill  which  overlooks  the 
village.  At  South  Ashfield  it  turned  west  and  di-ained  down  a  long  valley 
to  the  east  into  Conway,  and  from  this  point  I  was  uncertain  as  to  its 
course.  The  valley  it  has  followed  to  this  point  (South  Eiver  Valley)  runs 
east  into  the  Conway  Lake.  It  is  empty  of  sands  for  a  mile,  and  then 
begin  deposits  which  are  continuous  into  the  Conway  Lake. 

The  Ashfield  beds  seem  to  turn  south  just  at  the  town  line,  up  a  branch 
of  the  Soxxth  Eiver,  whose  valley  they  fill  for  a  long  way  soxxth,  to  the 
soxxthwest  corner  of  the  Greenfield  qxxadrangle,  and  then  repeat  the  opei'a- 
tion  already  described  at  the  nox'th  end  of  Bear  River  Lake  (p.  600). 
The  valley  in  which  we  are  followixig  up  the  deposits  ends  ixi  a  cxxl-de- 
sac,  but  is  continxxed  soxxthward  at  a  mxxch  higher  level  by  two  valleys, 
one  of  which  laxns  through  a  corner  of  Plainfield  and  along  the  east  of 
Moores  Hill,  in  Groshen,  iix  a  naiTOw  canyon,  and  thence  down  the  steep 
slope  into  Williamsbui-g  Lake,  and  the  other  more  directly  soxxth,  by  City 
Pond,  into  the  valley  of  Mill  River,  and  into  the  same  lake.  I  have 
represented  the  deposits  in  disconnected  patches  in  both  these  courses, 
because  much  of  the  way  the  valleys  are  so  naxTOw  that  all  traces  of  these 
eax'lier  occupaxits  have  been  swept  out  by  the  wild  floods  of  the  present 
brooks.  It  is,  of  course,  probable  that  the  Williamsburg  Lake  came  into 
existence  as  soon  as  the  ice  melted  back  from  it,  and  that,  as  the  ice 
retreated,  the  two  courses  I  have  last  traced  were  long  used  by  waters  at 
various  stages  of  this  retreat.  I  am  here,  however,  following  oxxt  the  last 
occupation  before  the  opening  of  the  Deei-field  River. 


602  GEOLOGY  OF  OLD  HAMPSHIEE  COCJNTY,  MASS. 

It  is  also  quite  possible  that  the  Ashfield  Lake  did  drain  into  the  Con- 
way Lake,  flowing  back  sonih  to  fill  the  cul-de-sac  described  above  with- 
out overflowing  to  the  south,  and  that  for  a  mile  east  along  the  South 
River  Valley  it  left  no  deposits.  My  attention  was  not  closely  directed  to 
the  point  when  on  the  ground,  and  my  opinion  was  formed  from  a  view  of 
the  entire  area  from  •  the  top  of  the  highest  hill  after  I  had  gone  carefully 
over  the  whole  region. 

THE  BUCKLAND  LAKE. 

If  we  follow  the  outer  contours  of  the  Ashfield  Lake  where  the  sands 
border  on  the  rocks,  we  shall  find  them  converging  just  north  of  Great 
Pond  upon  a  narrow,  rocky  canyon,  and  it  is  plain  that  the  waters  came 
through  this  passage  for  a  long  time  and  with  great  force,  bringing  the 
sands  which  extend  south  from  its  mouth.  The  drainage  of  Great  Pftnd 
is  southward,  but  a  small  rise  of  its  waters  would  send  it  north  through 
this  gorge.  On  entering  this  gorge  one  expects  it  to  rise  among  the  hills 
and  terminate  as  a  mountain  glen,  and  expects  to  find  the  brook  which  has 
brought  down  the  great  volume  of  sand,  but  a  short  distance  north  the 
valley  widens  somewhat  and  sinks  300  feet  with  great  suddenness,  so  that 
it  has  been  very  difiicult  to  carry  the  road  down  to  its  bottom.  One  sees 
immediately  that  the  ice  must  have  filled  this  deep  valley  (b^^,  PI.  XXXV, 
A)  when  the  waters  swept  across  its  back  and  through  the  narrow  gorge 
bearing  the  great  volume  of  sands  which  now  form  the  Ashfield  Plains,  for 
otherwise  the  deep  valley  to  the  north  must  have  been  filled  first.  That  it 
was  not  filled  and  then  reeroded  is  certain  from  its  bare,  rocky,  and  bowlder- 
covered  sides  and  from  the  abundant  openings  made  by  the  new  road  car- 
ried down  to  the  valley  bottom.  Taking  this  road,  we  go  down  sharply  to 
the  valley  bottom  over  till,  and  along  the  bottom  for  a  short  way  also  over 
till,  when  we  come  suddenly  upon  a  great  bank  of  fine,  well-bedded  sands, 
about  33  feet  high,  with  a  slope  as  regular  as  an  earthwork,  facing  us  (i.  e., 
facing  south),  and  extending  right  across  the  valley  and  resting  against  its 
walls.  It  is  like  a  dam,  only  breached  at  the  center  by  a  brook  which  runs 
north,  and  we  seem  to  be  in  the  bottom  of  an  abandoned  mill  pond.  Climb- 
ing to  the  top  of  the  slope,  Ave  find  it  is  the  southern  termination  of  a  great 
body  of  sand  which  once  filled  the  A'-alley  from  this  point  north  across  Buck- 
land  to  Buckland  Center,  and  which,  though  now  largely  eroded,  can  be 


THE  BUCKLAND  LAKE.  603 

ciisilv  t'nllowL'd  to  this  point  uiul  not  farther.  It  maintains  a  level  about 
200  feet  below  the  Ashfield  Lake  and  100  feet  above  the  Deerfield  River 
terraces. 

It  is  clear  that  after  filling  this  lower  valley  for  a  long  time  and  allow- 
ing the  waters  to  transport  the  great  body  of  sand  into  the  Ashfield  Lake  the 
ice  retreated  north  to  Buckland  Center  and  stood  there  for  a  time  (b"), 
maintaining  a  lake  of  great  depth,  which  still  drained  through  the  narrow 
canyon  and  across  the  sands  of  the  Ashfield  Plains,  producing  the  excep- 
tionally large  amount  of  erosion  of  these  sands,  while  the  sands  advancing 
along  its  own  bottom  were  checked  when  the  waters  passed  into  the  narrow 
gorge,  and  were  dropped  so  suddenly  that  a  steep,  submerged  delta  front 
was  formed.  Exactly  this  has  been  happening  now  for  several  years  at 
Millers  Falls,  where,  to  improve  the  railroad,  the  river  above  has  been 
turned  into  a  new  course  for  a  distance  through  deep  sands,  and  has  thus  a 
great  amount  of  material  at  its  disposal,  and  a  broad,  flat  bar  extending 
across  stream  is  creeping  down  into  the  deep  water  above  the  dam,  pre- 
senting a  sharply  sloping  delta  front  to  the  obstructing  dam,  as  do  the 
sands  here  to  the  obstructing  gorge. 

At  their  south  end  these  lower  sands  are  at  first  fine  grained,  well  sorted, 
cross  bedded,  and  undisturbed;  northward  they  are  soon  changed  to  coarser 
sand,  the  surface  becomes  pitted  with  kettle-holes,  and  the  sands  grow  coarser 
and  become  coarse  gravel.  At  last  glacial  bowlders  are  intermixed  and 
the  sand  is  twisted  and  tortuoiis  in  stratification,  and  it  seems  almost  to 
grade  into  till,  as  if  bowlders  were  cari'ied  south  with  masses  of  ice  by 
the  waters  and  mingled  with  the  sands,  or  as  if  the  ice  itself  had  advanced 
with  many  oscillations  and  disturbed  the  sands  (b"). 

The  ice  here  postulated  (b")  was  a  lobe  sent  southward  from  ice 
which  then  filled  the  Deerfield  River  Valley  and  much  of  the  high  ground 
north  of  the  river.  Another  lobe  projecting  southward  in  a  much  shorter 
valley,  and  one  rising  very  rapidly  to  the  high  level,  produced  another  con- 
siderable accumulation  of  sand  in  the  extreme  northeast  corner  of  Hawley, 
at  the  headwaters  of  Ruddock  Brook,  which  passes  down  the  valley  of 
Clessons  Brook  to  join  the  sand  described  already  as  extending  south 
from  Buckland  Center  up  the  same  brook.  They  join  at  the  south  line  of 
the  town  (at  Buckland  Four  Corners),  and  run  across  Ashfield  to  the  delta 
front  described  above. 


604  GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

THE  LAST    IMPORTANT    HALTING   PLACE   OF  THE   ICE   FRONT  ACROSS  THE 
BASIN  OF  THE  DEERFIELD  RIVER. 

On  page  573  I  have  traced  the  southern  boundary  of  the  ice  at  its  last 
marked  halt  across  the  eastern  half  of  Franklin  County,  and  a  similar  line 
may  be  drawn  across  the  western  half  of  the  county  by  conriecting-  the  ice 
barriers  which  formed  the  northern  limit  of  the  glacial  lakes  south  of  the 
Deerfield  and  kept  the  deep  valleys  tributary  to  this  river  empty  in  their 
lower  (northern)  reaches  across  from  Coleraine  to  Monroe. 

Directly  opposite  the  bamer  on  Dry  Hill,  in  Montague,  on  the  east  of 
the  Connecticut  River,  is  the  great  barrier  above  Bardwells  Ferry  (b^^)  on 
the  west,  and  these  may  be  looked  upon  as  two  synchronous  halting  places 
of  the  ice  front.  Between  these  the  lobe  of  the  ice,  which  at  the  same  time 
extended  down  the  Connecticut  Valley,  may  have  been  thrust  into  the 
clays  south  of  Deerfield  to  produce  the  disturbances  at  the  Wapping  cut- 
ting figured  on  PI.  XVIII  (p.  694).  West  of  Bardwells  are  the  Bear  River 
barrier  (b^^),  that  at  Buckland  Four  Corners  (b"),  that  on  Ruddock 
Brook  (b^^),  and  that  above  West  Hawley  (b^^). 

The  moraine  across  the  valley  of  the  Deerfield  above  the  mou.th  of 
Hoosac  Tunnel  (d)  lies  in  the  continuation  of  the  curved  line  which  joins 
these  ice  barriers,  and  as  these  barriers  on  both  sides  of  the  river  represent  a 
time  when  the  ice  halted  for  an  unusual  time,  and  as  they  lie  along  a  single 
curved  line,  one  may  assume  that  they  represent  a  single  and  exceptionally 
long  halting  place  of  the  ice. 

GLACIAL  LAKES  NORTH  OF  THE  DEERFIELD. 

Tlie  Hawley  Lake  requires  no  special  mention  (see  PI.  XXXV,  A),  and 
the  hia-h-level  sands  at  the  mouth  of  the  tributaries  of  the  Deerfield  on  the 
north  are  described  below.  Besides  these  there  is  an  interesting  lake  of 
small  dimensions  west  of  Shelburne  Center,  extending  to  the  river  and 
formed  when  the  Deei-field  Valley  glacial  lobe  projected  beyond  the  present 
mouth  of  Shiice  Brook,  throwing  back  its  waters  into  a  lake  which  drained 
over  a  rocky  sluice  i-unning  east  from  near  the  cemetery  toward  the  sawmill 
south  of  Shelburne  Center. 

Also  in  Charlemont,  when  the  Deerfield  Valley  glacier  extended  just 
beyond  the  village,  the  waters  of  Mill  Brook  were  thrown  east  at  a  high 


HIGH-LEVEL  DELTAS.  605 

level  round  tho  north  of  Bald  Mountain  and  down  the  valley  of  Hartwells 
Brook. 

One  finds  few  other  traces  of  obstructed  drainage  marked  by  stratified 
deposits  of  any  extent  across  the  high  ground  to  the  north  line  of  the  State. 

HIGH-LEVEL  DELTAS. 

When  the  reservoir  of  Mill  River  broke  through  the  dam  at  Williams- 
burg, in  1874,  the  waters  spread  out  fan-like  after  their  first  plunge  in  the 
area,  a  few  rods  below  the  dam,  and,  rapidly  losing  momentum,  they  were 
in  eff"ect  suddenly  overloaded  and  deposited  immediately  a  portion  of  the 
sand  they  were  transporting,  in  an  extended  flat-topped  layer  1  to  3  feet 
thick,  pushed  forward  in  broad  lobe-like  projections  and  bordered  down- 
stream by  a  sharp  terrace  slope  of  30°. 

All  the  streams  which  come  down  from  the  high  grounds  on  the  west 
side  of  the  basin  in  Westhampton,  Northampton,  Goshen,  Williamsburg, 
and  Whately  have  here  and  there  in  their  course  torrent  deposits  of  a 
size  all  out  of  proportion  to  their  present  dimensions,  especially  where  the 
streams,  after  running-  tlu'ough  narrow  channels,  deboiich  into  broad,  level 
portions  of  their  valleys. 

I  am  inclined  tQ  refer  all  these  deposits  to  occasional  violent  floods  when 
the  ice  was  melting  in  the  upper  part  of  the  drainage  area  of  the  brooks 
where  they  are  found,  and  think  they  may  have  been  made  much  as  were 
the  smaller  terraces  described  above  by  the  flooded  Mill  River  in  modem 
times.  At  the  same  time,  each  one  of  them  may  have  been  formed  while  a 
barrier  of  ice  still  filled  the  main  valley  and  blocked  up  the  mouths  of  these 
east-west  valleys,  forming  glacial  lakes  like  those  described  above. 

There  is  one  of  these  deltas  on  the  upper  portion  of  the  Sawmill  Brook, 
on  the  road  from  West  Farms  to  Westhampton.  It  hangs  in  a  remarkable 
way  over  the  broad  valley,  into  which  the  stream  passes  here  from  between 
the  hills,  its  downstream  slope  being  40°,  and  its  broad,  flat  sui-face  40  to 
50  feet  above  the  brook.  It  is  brought  out  flush  with  the  surface  of  the  hills 
on  either  side  of  the  brook,  as  if  it  had  been  built  up  against  a  wall  of  ice 
resting  against  these  hills  and  filling  the  valleys  below. 

Two  other  deltas  are  found  in  the  upper  waters  of  the  Mill  River  in 
Goshen,  one  at  the  first  road  crossing  above  the  reservoir,  where  the  brook 
comes  out  of  a  narrow  gorge  in  granitic  rocks.     This  is  pushed  out  into  the 


606       GEOLOGY  OF  OLD  HAMPSHIEB  COUNTY,  MASS. 

valley,  with  broad,  flat  surface  and  steep  downstream  slope,  and  the  stream 
has  now  cut  a  deep  channel  in  it  to  its  base.  The  other  occurs  about  a  mile 
below  the  reservoir  on  the  same  brook  and  east  of  Hubbard's  ledge.  This 
is  much  larger  than  the  one  higher  up,  and  its  surface  will  include  several 
hundred  acres. 

It  is  a  very  curious  circumstance  that  every  brook  coming  into  either 
of  the  transverse  valleys  of  the  Deerfield  and  Westfield  rivers  from  the 
north  is  flanked  at  its  mouth  by  a  distinct  terrace,  generally  triangular  from 
the  flaring  of  the  valley,  65  to  100  feet  above  the  stream,  and  now  divided 
down  its  center  by  the  deep  cutting  of  the  brook.  At  the  villages  of  Charle- 
mont,  Zoar,  Orange,  and  Huntington  are  fine  examples.  The  explanation 
that  they  were  caused  by  the  ice  lobe  coming  down  the  valley  and  being 
thrown  across  the  mouth  of  the  side  stream  is  nowhere  excluded  by  any- 
thing I  have  seen,  but  it  seemed  to  me  possible  that  they  might  owe  their 
origin  to  sudden  floods  of  overladen  waters  into  the  open  valley  in  the 
manner  described  above. 

The  features  at  Charlemont  admit  of  an  easy  interpretation  upon  this 
supposition;  opposite  the  entrance  of  the  tributary,  and  on  the  south  side  of 
the  Deerfield  River,  the  high  rocky  border  of  the  river  is  set  back  in  a  large 
semicircle,  and  the  south  half  of  this  semicircle  is  still  occupied  by  a  great 
body  of  sand  and  gravel,  whose  level  surface  slopes  south  as  if  in  continua- 
tion of  the  slope  of  the  delta  ten-ace  on  the  other  side  of  the  main  stream 
and  flanking  the  tributary.  Indeed,  if  one  could  restore  in  imagination  what 
must,  on  this  hypothesis,  have  been  removed  by  the  main  stream  and  by 
the  tributary  itself,  the  great  body  of  sand  would  form  an  alluvial  fan  extend- 
ing right  across  the  valley  of  the  Deerfield  into  the  great  cirque  described 
above,  the  southern  portion  of  which  fan  has  since  been  separated  from  the 
rest  by  the  erosion  of  the  Deerfield.  However,  a  southward-sloping  terrace 
on  the  south  side  of  the  Deerfield  would  not  be  an  impossibility,  and  the 
rock  of  the  region  is  so  monotonous  that  it  gives  no  clew  to  the  source  of  the 
sand.     These  terraces  were  called  delta  terraces  by  President  Hitchcock.^ 

In  order  not  to  multiply  colors,  I  have  colored  these  delta  terraces  with 
the  same  shade  as  that  which  would  be  applied  to  them  if  they  were  "glacial 
lakes" — that  is,  sands  deposited  by  the  obstructed  drainage  during  the  retreat 
of  the  ice. 


'  Surface  Geology,  p.  32. 


FLOOD  DEPOSITS  OF  TUB  WESTFIELD  KIVEE. 


607 


CHARACTER    OF    THE    TERRACED    FLOOD    DEPOSITS    OF    THE    WESTFIELD 

RIVER. 

From  tlie  j^oint  where  it  leaves  the  gates  of  the  mountain  on  the  west 
lino  of  Westtiekl,  the  Westfield  River  is  bordered  by  high-level,  coarse  beds 
alono-  the  narro^^'  A^alley  sides,  which  widen  somewhat  where  lateral  valleys 
come  in,  as  at  Russell,  Huntington,  and  Chester.     The  valley  narrows  above 


S.E. 


iN.W 


riQ.  33 Section  of  terminal  moraine  covered  by  liigh -level  flood  gravels  of  the  "Westfield  Eiver.    The  north  slope  is  caused 

by  caving  from  the  erosion  of  the  river.    Kussell,  just  below  station. 

Chester,  becomes  a  canyon  between  Becket  and  Washington,  widens  broadly 
across  Hinsdale,  and  joins  the  Housatonic  Valley  in  Dalton  with  increased 
width.  The  canyon  is  a  low  water-parting.  The  whole  central  part  of  Hins- 
dale is  deeply  covered  by  the  stratified  beds  of  a  glacial  lake  which  received 
its  waters  from  the  Housatonic  Valley  while  the  ice  clogged  the  lower  portion 
of  that  valley,  and  discharged  them  through  the  canyon  of  the  Westfield. 
It  thus  follows  that  the 
Westfield  Valley  was  for 
a  time  the  recipient  of  the 
deflected  drainage  of  the 
tipper  Housatonic  after 
the  ice  had  disappeared 
from  its  own  headwaters, 
and  the  many  bowlders  and 
pebbles  of  Cheshire  quartz- 

ite    found    down    the  valley    i-iq.  34 Sand  bowlders  crushed  by  the  ice  while  frozen,  from  just  south  of 

/2  ,        i  "T  •       "1     ^        4-"  *lie  telegraph  pole  seen  at  the  left  in  fig.  33, 

An  extremely  interesting  section  was  opened  by  the  Boston  and  Albany 
Railroad,  in  1896,  just  east  of  Russell,  which  throws  light  on  the  way  in 
which  the  terraced  beds  in  the  valley  of  the  Westfield  were  built  up,  as 
shown  in  fig.  33. 

In  the  upstream  portion  of  the  section  the  lower  half  is  a  complete 


608  GEOLOGY  OP  OLD  HAMPSHIEE  COUNTY,  MASS. 

terminal  moraine,  the  large  angular  bowlders  being  abundant.  In  the  upper 
portion  of  this  moraine  are  curious  separate  areas  of  stratified  sand,  discon- 
tinuous and  much  twisted  in  the  unstratified  mass  of  the  moraine.  One  of 
these  is  shown  in  fig.  34.  These  seem  to  be  plainly  parts  of  a  stratum  of 
sand  washed  upon  the  broad,  flat  moraine  and  then,  while  frozen,  broken 
into  blocks  by  the  farther  advance  of  the  ice  and  mixed  with  the  other 
bowlders  of  the  till.  This  shows  the  presence  of  a  lobe  of  the  ice,  moving 
as  a  valley  glacier  down  the  Westfield  Valley  and  halting  at  this  point. 

The  second  matter  which  is  well  illustrated  is  the  long-continued, 
steady,  torrential  flow,  and  the  high  level  of  the  Westfield  River  during  the 
time  immediately  following,  while  the  stream  was  receiving  the  waters  from 
the  melting  ice. 

On  the  downstream  side  (the  right  of  fig.  33)  the  current  quickly  filled 
up  the  area  in  the  lee  of  the  moraine  with  strongly  cross-bedded  sands  of 
medium  grain,  and  above  this  extends  for  many  rods  a  bed,  20  feet  thick, 
of  well-sorted  and  well-rounded  6-inch  gravel,  in  perfectly  horizontal  beds. 
Thei'e  is  rarely  a  pebble  above  8  inches  across,  and  almost  everything  below 
2  inches  across  is  washed  out  of  the  bed.  One  gets  here  another  side  of 
the  activity  of  the  strong  stream  which  brought  the  great  volume  of  sands 
to  build  up  the  broad  plains  of  Westfield  and  Southwick. 


CHAPTER   XIX. 

THE  CHAMPLAIN  PERIOD  (Continued). 

THE  CONNECTICUT  EI^TEE  LAKES. 

INTRODUCTION. 

"About  4  miles  above  South  Hadley  the  Connecticut  passes  between 
the  two  large  mountains,  Tom  and  Holyoke,  having  apparently  made  here 
in  ancient  times  a  breach  in  this  range  and  forced  its  passage.  By  the  old 
people  in  Northampton  I  was  informed  many  years  since  of  an  Indian  tra- 
dition that  the  great  valley  north  of  these  mountains  was  once  a  lake.  The 
story  is  certainly  not  improbable.  From  an  attentive  survey  of  the  country 
along  this  river,  I  have  no  difficulty  in  believing  that  a  chain  of  lakes  occu- 
pied the  several  expansions  at  some  distant  period  of  time.  Here  certainly 
the  g-eneral  geography  of  the  country  and  the  particular  appearance  of  the 
scenery  near  the  river  are  favorable  to  this  opinion."  ^  This  is  the  earliest 
geological  discussion  of  the  subject.  Still  more  interesting  is  the  earliest 
discussion  by  President  Hitchcock  of  the  ancient  lakes  of  the  Connecticut,^ 
which  he  believed  to  have  been  drained  by  the  cutting  down  of  the  gorge 
below  Middletown,  Connecticut,  and  their  lessened  remnants  drained  in 
turn  by  the  cutting  of  the  notches  in  the  trap  ridges. 

The  abundant  deposits  of  the  glacial  lakes  of  the  region  east  of  the 
river  in  the  main  antedate  those  of  the  valley  itself;  those  of  the  lakes  to' 
the  west  are  more  strictly  synchronous  with,  or  perhaps  a  little  later  than, 
the  valley  deposits. 

That  the  ice  was  thrust  forward  as  a  valley  glacier  beyond  the  front  of 
the  inland  ice  appears  clear  from  the  disposition  of  the  lower  of  these  lake 
and  stream  deposits  (mt,  PI.  XXXV,  C,  D)  along  the  eastern  border  (see 
p.  588).     That  it  was  thrust  forward  into  deep  water  in  the  valley,  in  its 

1  President  Timothy  Dwiglit's  Travels  in  New  England,  Vol.  I,  1822,  p.  325. 

2  Am.  Jour.  Sci.,  Ist  series,  Vol.  VII,  1824,  p.  16. 
MON  XXIX 39  609 


610  GEOLOGY  OF  OLD  HAMPSHIEE  GOUIirTY,  MASS. 

oscillations  overriding  beds  already  deposited,  and  that  it  "calved"  and  sent 
icebergs  down  the  valley,  will  appear  in  the  description  of  the  valley  beds 
here  given.  Because  of  the  peculiar  configuration  of  the  valley,  this  is 
most  plainly  discernible  in  the  Hadley  basin,  less  so  in  the  Springfield 
basin  to  the  south,  and  in  the  Montague  basin,  though  in  the  last  it  can 
be  clearly  proved. 

One  must  recall  briefly  the  shape  of  the  Connecticut  Valley,  as  already 
defined  (p.  9),  while  occupied  by  the  Triassic  sandstones,  and  as  now  reoc- 
cupied  by  the  Connecticut  lakes.  The  eastern  rocky  bluft"  runs  south  one 
point  west  from  Northfield  to  Mount  Toby,  turns  on  this  and  runs  south- 
west by  south,  but  more  irregularly,  to  the  Belchertown  Ponds  at  the  east 
end  of  Mount  Holyoke,  and  then  south  to  the  south  line  of  the  State. 

The  western  line  runs  from  near  the  river  in  Vernon  south  through 
West  Northfield,  turns  west  across  Bernardston  and  along  the  north  line  of 
Greenfield  to  its  northwest  corner,  where,  near  the  mouth  of  Leyden  Glen, 
Mrs.  Williams  was  killed  by  the  Indians  in  1718.  It  turns  southward  again 
along  the  west  border  of  the  town.  Greenfield  was  laid  out  so  as  to  include 
all  the  flat  country,  and  the  barren  hills  were  left  for  Shelburne  and 
Leyden.  The  line  goes  south  to  Elizabeth  Rock,  in  Northampton,  at  the 
apex  of  the  "big  bend"  of  the  Connecticut.  Here  it  is  set  back  west 
again,  as  before,  to  include  Northampton,  and  goes  on  one  point  west  of 
south  to  the  south  line  of  the  State  in  Southwick. 

The  r-shaped  Holyoke  range  cut  off  the  Springfield  basin,  and  the 
L-shaped  Deei-field-Toby  range  cut  off  the  Montague  basin  on  the  south 
and  north,  respectively,  from  the  Hadley  basin.  So  that,  south  of  the 
Holyoke  range,  the  area  was  greatly  sheltered  from  the  ice  so  soon  as  it 
sank  below  the  crest  of  the  range,  and  the  ice  in  the  Hadley  basin  was 
projected  into  the  southern  continuation  of  the  latter  along  the  western  foot 
of  this  range,  as  the  southwesterly  striae  there  indicate. 

On  the  other  hand,  a  separate  lobe  of  the  ice  occupied  the  main  valley 
of  the  Connecticut  in  the  Montague  basin,  and  another  lobe  occupied  the 
northwestern  lateral  extension  of  the  Hadley  basin  in  Deei-field  and  Green- 
field, the  latter  lingering  longest  in  Greenfield — indeed,  till  after"  the  maxi- 
mum of  the  flood  had  passed. 

The  waters  occupied  the  basin  while  it  was  still  largely  encumbered 
with  the  remnants  of  the  glacial  ice,  and  during  all  the  time  of  the  deposition 
of  the  central  clays  floating  ice  was  abundant.     The  occurrence  of  arctic 


THIO  CONNECTICUT  lUVEK  LAKES.  611 

plants  in  t\w  upi)er  portion  of  the  clays  is  in  harmony  with  this  state  of 
things,  and  the  many  kettle-holes  in  the  high  terrace  of  this  age  are  in  part 
due  to  masses  of  ice  covered  deeply  by  the  sands  of  nnusual  floods  and 
remaining  for  long  periods  in  the  frozen  soil.  We  may  be  reasonably  sure 
also  that  no  time  elapsed  between  the  disappearance  of  the  ice  and  the  full 
occupancy  of  the  valley  by  the  flood  watei's.  The  frontal  lobe  of  the  ice 
was  buoyed  up  and  floated  away  in  the  advancing  waters. 

From  the  first  disappearance  of  the  ice  the  waters  were  never  lower 
than  180  feet  above  sea  level  in  the  central  part  of  the  State  until  after  the 
culmination  of  the  flood  period,  when  the  waters  began  to  settle  to  their 
present  level,  because  over  the  broad  area  where  the  clays  have  been  left 
undisturbed  they  are  continuous  from  this  level  downward,  and  show  no 
intercalation  of  pebble  or  sand  beds  and  no  interruption  of  their  regular 
lamination,  and  they  extend  clear  across  the  valley  from  the  Pelham  range 
to  Northampton. 

While  these  "Champlain"  clays  were  being  laid  down  over  the  broad 
bottom  of  the  valley  its  swollen  tributaries  were  bringing  in  coarse  mate- 
rial along  its  borders,  and  the  waters  of  the  lake  itself  were  eating  into  its 
banks,  sweeping  off"  the  loose  glacial  debris  and  wearing  narrow  shelves 
in  the  rocks  themselves,  and  especially  cutting  deep  into  the  sides  of  the 
great  drumlins  which  are  so  abundant  on  both  sides  of  the  valley,  and 
carrying  the  material  so  gained  out  into  deeper  water.  It  is  C^mte  certain 
that  but  a  small  portion  of  these  shoreward  deposits  have  been  carried  far 
south  by  the  flooded  river  itself  They  are  the  confluent  deltas  of  its  trib- 
utaries. Where  we  can  trace  the  layers  of  the  clay  and  their  delicate  sand 
partings  shoreward,  we  find  the  latter  growing  coarser  and  thicker,  and 
passing  continuously  into  the  thick  sand  and  gravel  layers  which  form  the 
"front  set"  beds  of  the  deltas  and  bars.  The  fine  flat  clay  layers  continue 
on  imthickened  up  the  delta  fronts,  more  and  more  separated  by  the  thick- 
ened sand  layers,  and  grade  into  fine  sand  or  are  prolonged  only  as  the 
partings  between  the  thick  sand  or  gravel  beds.  Hence  we  may  be  sure 
that  the  great  body  of  the  central  clays  is  strictly  contemporaneous  with 
the  great  body  of  the  shoreward  gravels,  and  that  the  whole  has  the 
character  of  a  lake  deposit. 

We  shall  need  all  the  light  we  can  obtain  in  our  attempt  to  reproduce 
the  history  of  the  valley  from  the  reestablishment  of  the  drainage  to  the 
subsidence  of  the  waters.     The  stream  may  have  been  at  first  like  the  body 


612  GEOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 

of  water  which  flows  out  from  under  one  of  the  Grreenland  glaciers;  then, 
hke  the  great  river  Yukon,  with  its  vast  volume  and  lakelike  expansions, 
and  finally,  like  the  Rhone,  heading  in  a  glacier  among  our  smaller  New 
England  Alps.  As  we  trace  around  the  valley  the  great  bench  which 
represents  the  completed  work  of  the  chain  of  lakes,  we  must  imagine  the 
waters  up  to  and  over  its  level,  the  tributaries  entering  at  its  outer  border,^ 
and  the  deep  notches  they  have  cut  in  the  bench,  as  in  later  time  they 
followed  the  lessening  waters  toward  the  center  of  the  basin,  again  filled  to 
its  level.  We  must  restore  also  many  smaller  gulches  cut  in  the  bench 
where  there  are  now  no  running  streams.  We  must  be  on  our  guard  for 
places  where,  from  want  of  material  or  the  rapid  flow  of  the  waters  in  con- 
tracted places,  the  bench  was  not  built  up  to  the  full  level,  and,  most 
difficult,  must  try  to  form  some  estimate  of  the  amount  carried  away  or 
rearranged  by  the  river  itself  as  it  sank  from  its  greatest  height  to  its 
present  level.  We  must  inquire  also  whether  kame  material — stratified 
beds  formed  while  the  ice  still  held  the  waters  above  their  normal  level — 
does  not  blend  with  and  disguise  the  true  terrace  of  later  time,  and  from 
a  study  of  the  inner  structure  of  the  beds  must  seek  to  learn  whether  it 
rose  gradually  to,  or  asserted  from  the  first,  its  highest  level. 

In  no  part  does  the  map  need  more  to  be  supplemented  by  sections 
than  here,  for  it  can  show  only  those  portions  of  the  lake-shore  deposit 
which  have  escaped  degradation  and  of  the  lake-bottom  beds  which  have  not 
been  molded  anew  by  the  river  into  terraces  of  a  later  time  and  covered  by 
the  layers  of  river-bottom  sands  and  loess  (t--t',  PI.  XXXV),  which  have 
for  the  most  part  thinly  concealed  rather  than  replaced  the  more  massive 
deposits^  of  this  age.  The  word  "terrace" — which  we  employ  in  geological 
discussions  with  a  latitude  of  meaning  for  the  most  part  useful  but  some- 
times liable  to  be  misleading  or  indefinite,  and  which  from  the  great  develop- 
ment of  this  structural  form  along  the  Connecticut  always  suggests  here  the 
ordinary  river-erosion  terraces — I  am  inclined  to  replace  by  the  word 
"bench"  in  the  following  descriptions,  to  emphasize  the  many  points  of 
distinction  between  the  highest  level  as  compared  with  the  remaining 
levels  we  pass  over  in  going  down  from  the  high  ground  to  the  river. 

If  we  take  a  single  terrace  lower  in  the  series  for  examination,  we  shall 
find  it  a  plain  sloping  with  the  river  and  bordered  on  the  side  away  from 


i  OatBide  1  s  ]i  oq  PI.  XXXV. 
'  See  G.    K.  Gilbert,  Outlet  of  Lake  Bonneville :  Am.  Jour.  Sci.,  3d  series,  Vol.  XIX,  1880,  p.  341. 


THE  CONNECTICUT  RIVER  LAKES.  613 

the  litter  1)\'  a  scai'p  risin<>'  up  I'nnu  tlio  terrace  (tluf  l)ank  of  tlie  river 
when  the  teiTace  was  part  of  its  bottom),  and  limited  toward  the  river  by  a 
descending  scarp  which  was  the  river  bank  at  a  later  time,  generally  when 
the  terrace  made  i)art  of  its  flood  plain.  Corresponding  to  this,  we  shall 
find  the  plain  covered  with  the  meadow  loam  laid  down  in  the  floods  of  the 
river,  and  under  this  loam  the  strong  river-bottom  sands  of  an  earlier  date, 
the  last  underlain  unconformably  by  older  deposits  which  the  river  had  not 
reached  and  eroded  while  it  flowed  above  them. 

On  the  other  hand,  we  shall  find  the  highest  terrace  or  bench  bounded 
outwardly  by  a  slope  which,  as  to  its  material  and  structure,  has  no  relation 
to  the  river.  At  most,  the  river  has  undermined  this  more  or  less  exten- 
sively at  the  water  level,  and,  by  caving,  an  escarpment  of  till,  sandstone, 
or  gneiss  has  resulted.  The  terrace  itself,  widening  iiito  extensive  sand 
or  gravel  plains  where  the  alluvial  cones  or  deltas  of  the  side  streams  were 
thrust  out  into  the  lake,  narrows  in  places  remote  from  these,  and  its  level 
is  often  represented  by  shelves  in  the  sandstone  scarcely  covered  by  sands, 
or  in  the  till  deeply  concealed  by  gravels  concentrated  from  the  till  itself. 
Pursuing  the  same  level,  we  soon  come  upon  the  continuation  of  the  normal 
sand  beds  which  make  the  bulk  of  the  bench. 

Inwardly,  however — that  is,  toward  the  center  of  the  lake — especially 
around  all  the  Hadley  basin  and  its  prolongation  in  the  Deerfield  and  East- 
hampton  valleys,  the  terrace  is  for  the  most  part  bounded,  not  by  an 
escarpment  of  steep  and  constant  pitch — an  abandoned  river  bank — but  by 
the  slope  of  passage  from  shallow  to  deep  water.  This  is  sharpest  and  most 
constant  on  the  face  of  the  large  deltas  (but  here  of  less  angle  than  in  the 
former  case,  as  the  highest  angle  at  which  sands  come  to  rest  under  water  is 
less  than  that  assumed  in  air),  less  and  less  marked  in  other  places,  until  at 
last  the  case  occurs  where  from  the  rocky  bank  the  sands  pass  with  gentle 
and  continuous  slope  to  the  deepest  central  line,  where  was  the  thread  of 
the  current,  and  rise  in  the  same  way  to  the  opposite  bank. 

This  slope  of  passage  I  have  called  a  scarp  of  deposition,  or,  as  locally 
synonymous  therewith,  the  delta  front,  in  contradistinction  from  the  ordi- 
nary scarp  of  erosion.  On  the  map  the  normal  high  terrace  or  bench 
(1  s  h,  PI.  XXXV)  and  its  widening  into  great  delta  flats  are  not  separately 
indicated.  One  passes  by  a  scarp  of  deposition  to  the  broad  area  of  the 
old  lake  bottom  (1  b  t),  which  was  synchronous  with  the  bench  itself. 


614  GEOLOGY  OE  OLD  HAMPSHIEE  COUl^TY,  MASS. 

The  three  great  water  areas  indicated  ah-eady  were  sufficiently  broad 
and  sufficiently  separated  to  justify  one  in  calling  them  lakes,  and  these  two 
terraces  would  then  be  called  the  lake-shore  and  the  lake-bottom  deposits 
(1  s  h  and  1  b  t).  This  is  further  justified  by  the  lakelike  mode  of  accumu- 
lation of  the  sediments  in  these  areas,  and  allows  me  to  use  the  term  "old 
river  bottoms"  for  the  abandoned  beds  of  streams  in  old  oxbows. 

The  second  terrace  or  the  old  lake  bottom,  unlike  the  other  terraces,  is 
a  surface  depending,  not  upon  the  level  of  the  water  at  the  time  of  its  forma- 
tion, but  upon  the  water  level  and  the  amount  of  material.  The  valley 
widens  southwardly,  which  has  the  same  effect  as  if  the  supply  of  material 
decreased  in  this  direction.  As  a  result,  the  lake-bottom  level  sinks  gradu- 
ally as  one  proceeds  toward  the  south  relatively  to  the  lake  bench,  w  the 
deposition  scarp  which  sejDarates  the  two  increases  in  height.  The  third 
terrace,  counting  from  the  shore  line,  is  generally  the  uppermost  flood  plain 
of  the  normal  Connecticut  River. 

This  brinsrs  about  the  curious  result  that  the  second  and  third  terraces 
change  places  as  we  go  south,  the  change  taking  place  between  the  Mon- 
tague and  the  Hadley  lakes;  that  is,  the  Montague  Lake  was  a  fiUed-up 
lake,  and  as  we  go  inward  from  its  shore  line  we  pass  by  a  slight  scarp  of 
deposition  to  the  remnant  of  the  lake  bottom  at  a  level  but  little  loAver 
than  that  of  the  bench  itself.  We  descend  next  by  a  scarp  of  erosion  to 
a  marked  terrace  (t*)  that  crosses  the  northern  line  of  the  State  with  a 
heiffht  of  310  feet,  which  I  have  often  called  the  intermediate  terrace  or 
the  Lily  Pond  terrace,  formed  during  the  early  decline  of  the  flood  by  the 
rocky  barrier  at  the  Lily  Pond  in  Grill  (see  PI.  XXII,  p.  724).  This  is  at 
times  broken  into  two  or  more  terraces.  We  descend  then  finally  by  an 
erosion  scarp  to  the  group  of  terraces  but  little  above  the  present  flood 
plain  of  the  river,  and  still  lower  to  the  incomplete  terraces  which  lie  below 
that  level,  both  which  groups  have  been  formed  by  the  river  in  its  j)resent 
size  and  condition.  The  intermediate  terrace  (t*)  was  thus  excavated  in 
the  lake-bottom  beds — that  is,  inside  the  lake  bottom. 

Farther  south,  in  the  broader  Hadley  Lake,  the  filling  had  not  pro- 
gressed far  enough  to  obliterate  the  lake,  and  the  equivalent  of  this  third 
terrace  (t*)  is  found  as  the  first  terrace  below  the  bench,  generally  slightly 
marked  and  excavated  in  the  upper  portion  of  the  deposition  scarp  which 
had  connected  the  shore  and  deep-water  deposits  of  the  highest  floods — that 


FLOOD  DEPOSITS  IN  MONTAGUE  BASIN.  615 

is,  outside  the  lake-bottom  deposit.  In  the  first  case  the  order  is,  (1)  lake 
bench,  (2)  lake  bottom,  (3)  310-foot  terrace  (t*);  in  the  second,  (1)  lake 
bench,  (2)  the  contiiuiation  south  of  t*,  (3)  lake  bottom. 

In  other  words,  the  Hadley  Lake  continued  through  the  whole  period, 
and  its  lake-bottom  beds  are,  strictly  speaking,  a  little  later  in  age  than 
those  of  the  northern  basin.  It  seems  by  far  best  to  represent  all  the  lake- 
bottom  deposits  b}^  one  color,  as  I  have  done. 

DETAILED  DESCRIPTION  OF  THE  FLOOD   DEPOSITS  IN  THE   MONTAGUE    BASIN. 

This  description  is  in  continuation  of  the  interesting  account  of  the 
terraces  of  the  Connecticut  in  New  Hampshire  given  by  Mr.  Wai-ren 
Upham  in  the  Geology  of  New  Hampshire,  Vol.  Ill,  page  19.  I  may  men- 
tion that  I  accept  the  criticism  of  Professor  Dana^  of  the  view  taken  by  Mr. 
Upham,  that  the  deltas  thrust  out  into  the  main  valley  are  often  above  the 
highest  "normal"  terrace  of  the  flood  time,  and  consider  these  deltas  as 
marking  by  their  levels  the  true  height  of  the  flood  waters,  and  look  upon 
the  lower  level  of  the  highest  terrace  which  connects  these  deltas  as 
explained  by  a  lack  of  material  in  the  intermediate  spaces.  I  can  not, 
however,  accept  the  other  criticism  of  Professor  Dana  that  the  esker  traced 
down  the  valley  by  Mr.  Upham  has  no  existence  as  an  eai'lier  structure 
antedating  the  flood  gravels  of  the  open  valley. 

The  Montague  basin  is  narrow — about  a  mile  wide — where  it  enters  the 
Warwick  quadrangle  in  Vernon  (PI.  XXXV,  C),  and  it  retains  this  width 
across  the  area,  connecting  at  the  highest  water  stand  westward  around 
Mount  Hermon  with  the  northern  or  Greenfield  lobe  of  the  Hadley  Lake. 
As  it  enters  the  Greenfield  quadrangle  at  Millers  Falls  it  widens  to  above  6 
miles,  and  is  connected  again  at  flood  level  by  several  narrow  passes  in  the 
trap  ridge  with  the  northern  lobe  of  the  Hadley  Lake  at  Greenfield.  It 
connects  by  the  narrows  at  Sunderland  with  the  main  Hadley  basin.  It 
was  a  nearly  filled-up  lake.  The  main  stream  quite  filled  its  rather  narrow 
valley  down  to  Millers  Falls,  where  it  widens,  and  here  the  heavy  contribu- 
tions of  the  Millers  River  filled  the  whole  widened  valley.  The  distinction 
between  the  shore  flats  (1  s  h)  filled  to  the  highest  effective  level  of  the 


'Am.  Jour.  Soi.,  3cl  series,  Vol.  XXII,  p.  431. 


61  6  GEOLOGY  OF  OLD  HAMPSHIRE  COUl^TT,  MASS. 

waters  and  the  unfilled  portions  (1  b  t),  10  to  50  feet  lower,  can  be  clearly 
made  oiit.  Karnes  rise  out  of  the  shore  flats,  which  are  often  kettle-holed 
and  plainl}^  deposited  in  the  presence  of  remnants  of  the  ice ;  but  there  are 
no  continuous  and  important  "moraine  terrace"  beds  fringing  the  eastern 
rocky  slope  and  raised  above  the  flood  level  of  the  waters.  These  shore- 
ward plains  sink  by  easy  construction  scarps  to  the  bottom  flats  in  which 
the  erosion  terraces  (t*  to  t*)  have  been  cut. 

THE  NORTHERN  LOBE  OF  THE  LAKE. 

From  the  hill  which  overlooks  the  hotel  in  South  Vernon,  Vermont,  just 
on  the  State  line,  one  sees  the  river  for  a  long  way  northward  flowing  in  a 
narrow  channel  bounded  on  both  sides  by  high  lands  which  slope  rapidly 
to  the  stream  and  leave  place  for  only  narrow  terraces.  Nearer,  the  sand 
flats  spread  westward  from  the  river  around  the  base  of  a  prominent  hill  (t) 
which  rises  to  the  north,  and  bending  north  suiTOund  this  hill.  The  sands 
are  very  thick,  and  seem  to  rise  a  little  above  the  highest  probable  flood  level 
for  this  latitude,  about  400  feet,  which  would  indicate  that  they  were  brought 
in  behind  this  hill  while  the  ice  filled  the  main  valley  and  were  not  wholly 
planed  down  by  the  later  stream.  Around  the  south  spur  of  the  hill  east 
into  the  open  valley  the  sands  sink  rapidly  to  the  lake  bottom  at  322  feet, 
as  they  failed  to  receive  further  protection  in  the  lee  of  the  hill,  and  the  plain 
of  fine  sand  sinks  riverward  to  307  feet,  and  is  continued  in  a  remnant  which 
lies  just  north  of  the  station  with  a  height  of  297  feet,  cut  off  from  the  rest  by 
an  old  channel  of  the  river. 

The  old  lake  bottom  commences  again  just  opposite  the  hotel  in  South 
Vernon,  it  having  been  cut  away  by  erosion  at  the  State  line,  and  extends 
southward  as  a  broad,  level  plain,  down  the  center  of  which  the  road  to 
Bemardston  passes.  On  its  outside  it  rests  for  more  than  a  mile  against 
the  rocks,  which  rise  first  abruptly  and  then  more  gradually,  and  present  a 
rugged  and  irregular  surface,  thinly  covered  by  loose  till.  On  this  surface 
the  river  has  deposited  nothing.  Where  the  Bernardston  road  mounts  from 
t*  to  the  top  of  this  terrace  a  section  showed — 

Feet. 

1.  Very  fine,  loamy,  iinlamiuated  sand 6  to  8 

2.  Well- washed  granite  gravel,  pebbles  one-fourth  inch 7 

3.  Fine  sand  in  great  thickness. 


THE  BENNKTTS  UUOOK  I'LAIN.  617 

The  upper  striiiiun  extended  over  the  wliole  surface  of  the  plahi  and 
seems  to  have  l)een  deposited  when  the  river  reached  this  level  only  in  its 
floods.  FoUowino-  down  this  jjlain  (1  h  t)  for  more  than  a  mile  one  is  con- 
fronted by  a  great  escarjjment  which  stretches  obliquely  across  the  road 
from  the  rocky  hillside  to  the  river  bluff,  and  rises  80  feet  above  the  lower 
plain,  or  380  feet  above  the  sea,  and  reaches  400  feet  when  it  rests  against 
the  rocks.  Seen  from  the  hills  across  the  river,  its  upper  edge  is  sharply 
preserved  and  its  horizontally  fluted  slope  is  clearly  a  portion,  preserved 
intact,  of  the  riverward  face  of  a  great  submerged  bank  and  not  a  stream- 
cut  scarp.  The  road  rises  to  the  surface  of  this  high  plain  next  to  be 
described. 

THE  BENNETTS  BROOK  PLAIN,  OR  MORAINE  TERRACE. 

The  plain  stretches  far  southward  into  Bernardston  and  Grill,  expanding 
rapidly  to  more  than  a  mile  in  width.  It  is  the  true  high  terrace  or  bench 
(1  s  h)  of  the  Montague  Lake.  The  surface  is  as  level  as  any  river  terrace 
for  more  than  a  half  mile  back  from  the  edge  overhanging  the  river,  and  for 
a  long  way  south.  A  small  reef  of  rock  projects  above  the  general  surface 
near  its  northern  end,  and  the  gravel  is  scooped  out  in  front  and  along  the 
sides,  the  grooves  running  out  southward  into  the  common  level  of  the 
plain  exactly  as  the  sands  are  hollowed  out  around  the  pier  of  a  bridge. 
Shallow,  empty  watercourses  run  over  its  surface  and  toward  the  river. 

With  these  exceptions  the  plain  shows  a  true  level  as  one  rides  along 
the  road  or  crosses  it  at  any  point  going  east  toward  the  river,  a  distance  in 
many  places  more  than  a  half  mile.  If,  however,  one  goes  westward  to  the 
mountain,  taking,  for  instance,  the  field  road  to  A.  Whitehead's,  north  of  the 
Lily  Pond,  in  about  100  rods  flat  hollows  begin  to  appear,  at  first  only 
5  to  6  feet  deep  and  20  to  30  feet  in  radius,  but  growing  deeper  and  closer 
together  tintil  the  whole  surface  is  covered  by  regular  kettle-holes  about  20 
feet  deep  and  separated  only  by  narrow  ridges  which  rise  everywhei'e  just 
to  the  level  of  the  plain,  and  the  road  goes  up  and  down  as  if  it  were 
built  along  the  edge  of  a  saw.  Farther  on  the  cols  between  these 
hollows  grow  lower,  and  by  degrees  the  kettle-holes  merge  into  broad, 
irregular  depressions,  several  of  which  are  occupied  by  ponds  50  to  75  rods 
long  and  about  40  to  50  feet  below  the  general  surface.  These  ponds  were 
almost  wholly  dried  up  in  the  dry  time  when  I  examined  them,  and  showed 


618  GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

flat  sand  bottoms  out  over  which  peat  meadow  was  spreading.  The  road 
we  have  followed  ends  in  a  depression,  elongated  in  the  direction  of  the  old 
shore  line  and  extending  to  the  mountain,  which  has  been  further  hollowed 
out  by  the  brook  that  now  runs  in  it. 

The  striking  peculiarity  in  connection  with  the  appearance  and  grad- 
ual development  of  this  system  of  kettle-holes  is  that  they  are  excavated 
in  a  quite  level  plain,  and  from  a  distance  one  would  have  no  suspicion  of 
their  existence.  At  first  they  do  not  interfere  with  the  manifest  levelness 
of  the  surface,  and  as  they  grow  deeper  the  ridges  between  them  are  flat- 
topped  and  of  the  common  level,  and  only  as  the  depressions  are  crowded 
together  do  the  ridges  become  at  first  sharp-edged  and  then  sink  into  passes 
between  the  hollows,  until,  against  and  running  southward  parallel  with  the 
mountain,  there  is  a  broad  space  where  almost  everything  has  sunk  irregu- 
larly below  the  common  level.  Along  this  line  the  surface  of  the  plain  is 
made  up  of  finely  rounded  gravel,  with  cobblestones  6  to  12  inches  across, 
and  the  exposures  in  the  roadside  where  the  highway  descends  on  the 
north  are  of  the  same  material  for  perhaps  20  feet  downward  from  the 
surface.  Farther  south  Bennetts  Brook  runs  across  the  plain  to  the  river, 
at  the  bottom  of  a  gorge  140  feet  deep,  bounded  by  a  single  steep  sand 
slope  on  either  side,  without  as  yet  cutting  down  to  the  ledge. 

Following  the  northern  road  down  the  slope  to  the  ferry,  one  finds  that 
the  great  plain  is  here,  on  its  front  edge,  also  made  up  above  of  finely 
rounded  gravel  of  great  thickness,  consisting  of  cobblestones  6  to  12  inches 
in  length.  Below  a  point  80  feet  above  the  river,  or  280  feet  above  the 
sea,  fine,  horizontally  laminated  sands  underlie  the  gravels,  and  similar 
fine  laminated  claylike  sands  appear  at  the  same  height  in  the  road  going 
southwest  up  from  the  same  meadow.  The  surface  of  the  bench  remains . 
unchanged  to  and  beyond  the  railroad  crossing.  Here,  just  on  the  south 
hue  of  West  Northfield,  the  configuration  of  the  surface  was  originally 
much  modified  by  the  great  quadrangular  mass  of  Mount  Hermon,  Avhich 
rises  in  the  midst  of  the  plain.  The  surface  of  the  latter  was  depressed  by 
the  sweep  of  the  waters  around  this  obstruction,  especially  on  the  west, 
where  they  entered  the  narrow  passageway  between  this  hill  and  the  border 
of  the  basin,  a  passage  through  which  the  road  and  the  railroad  now  go, 
and  this  is  expressed  by  the  sinking  of  the  plain  eastward  from  375  feet  at 
the  railroad  crossing  to  about  330  feet  at  the  eastern  brow  of  the  terrace. 


JUNCTION  OF  MONTAGUE  AND  HADLEY  LAKES.  619 

Nearer  tin-  ohstriu'ting  lull  a  brook  lias  taken  advantage  of  the  depres- 
sion and,  as  hai)pens  very  often  in  similar  circumstances — so  often,  indeed,  as 
to  make  it  tlu'  rule — has  worn  down  between  the  hill  and  the  terrace  gravels, 
slipping  down,  as  it  were,  upon  the  northward-sloping  side  of  the  sand- 
covered  drmulin  and  eroding  for  the  most  part  in  the  sands  of  the  terrace. 
The  plain  is,  however,  clearly  continuous  through  this  pass  around  the  west 
side  of  tlic  hill;  on  the  east  side  it  has  been  removed  or  terraced  down  to 
lower  levels  by  the  river.  A  distinct  esker  ridge,  elevated  about  20  feet 
above  the  level  of  the  plain,  and  older  than  it,  runs  along  southeastwardly 
through  the  pass  and  near  the  mountain  side,  ending  opposite  the  second 
crossing. 

South  of  the  village  of  Gill  for  a  long  distance  lower  terraces  abut 
directly  upon  the  steep  rocks,  and  only  traces  of  the  high  terrace  bench  occur 
where  the  road  comes  down  from  the  hill  to  the  Noi-thtield  Farms  ferry.  A 
section  in  the  latter  showed  about  20  feet  of  clay,  its  surface  about  70  feet 
above  the  river  and  150  above  the  sea  Above  this  are  sands.  From  this 
point  the  vertical  rock  wall  of  the  canyon  bounds  the  river,  and  the  high 
terrace  disappears,  except  in  traces,  until  one  reaches  Turners  Falls. 

THE  EXTENSION  OF  THE  FLOOD  GRAVELS  WESTWARD  THROUGH  THE  BERNARDSTON 
PASS  TO  JOIN  THE  HEAD  OP  THE  HADLEY  LAKE  IN  THE  NORTH  OF  GREENFIELD. 

North  of  Mount  Hermon  the  mountain  side,  against  which  on  the  west 
the  great  bench  we  are  following  has  rested,  swings  abruptly  westward  and 
continues — maintaining  its  height — westward  to  Bernardston.  Between  this 
hillside  and  Mount  Hermon  the  gravels  of  the  Bennetts  Brook  plain  extend 
westward  through  a  narrow  pass,  200  rods  wide,  which  I  have  for  conveni- 
ence called  the  Bernardston  Pass.  This  is  occupied  by  the  highway  and 
the  railroad  running  past  Bernardston.  The  gravels  are  naturally  lowered 
in  the  narrow  portion  of  the  pass,  but  rapidly  regain  their  high  level  of  392 
feet  as  the  pass  widens  southwestwardly  and  the  sands  expand  into  a  broad, 
very  level  plain  which  widens  north  up  the  fiord  valley  of  Dry  Brook.  It 
doubtless  owes  its  abundant  sands  largely  to  the  great  stream  which  flowed 
down  this  valley,  and  its  freedom  from  kettle-holes  is  due  to  the  fact  that 
this  stream  continued  to  flow  after  the  main  current  had  ceased  to  flow 
westward  through  the  pass  and  the  ice  had  completely  jxielted  away  beneath 
the  sands. 


620       GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

On  the  south  the  plaui  ends  very  abruptly  over  the  basin  in  which  lies 
the  village  of  Gill,  and  Dry  Brook  has  been  kept  up  to  the  level  of  the 
plain  by  a  reef  of  schist  which  rises  in  its  front  edge  and  over  which  the 
brook  falls  rapidly  into  the  rounded  valley  below.  The  latter  is  a  high 
basin,  with  sides  and  bottom  of  till,  and  how  far  it  has  been  filled  up  to  the 
flood-plain  level  and  then  cleared  otit  again  by  Dry  Brook  and  its  many 
tributaries  it  is  hard  to  decide. 

Westward  across  Dry  Brook  the  high  plain  is  soon  again  supported 
on  the  south  side  by  high  ground,  as  well  as  on  the  north,  and  soon 
begins  to  develop  kettle-holes  and  merges  into  a  kame  area  exactly  as 
described  in  the  last  section.  Its  sm-face  dips  very  shghtly  westward,  it 
beinp-  396  feet  hidi  at  its  eastern  side,  392  feet  at  its  western  border,  where 
it  begins  to  break  up  into  kettle-holes,  and  389  feet  farther  west  in  the 
middle  of  the  kame  area. 

To  one  looking  down  on  this  broad  area  of  intricately  reticulated 
gravel  ridges,  short  kames,  and  interrupted  plains,  the  whole  forming  a 
typical  "kame  landscape,"  it  seems  clear,  from  the  configuration  of  the  sur- 
face and  the  trend  of  the  broken  ridges,  that  the  cim-ent  flowed  west  into 
the  Greenfield  basin.  A  restored  surface  carried  through  the  highest  por- 
tions of  the  ridges  sags  along  the  middle  and  cuts  the  high  ground  north 
and  south  like  a  shore  line. 

The  material  also  in  the  pass  consists  largely  of  pebbles — mostly  under 
6  inches  in  diameter,  but  some  a  foot  long,  in  part  quite  well  worn  but  in 
part  only  battered — of  the  common  gneiss  and  quartzite  which  abound  in 
the  main  valley  farther  north.  Westward  beyond  the  narrows  the  gravels 
grow  much  finer. 

In  the  western  part  of  the  kame  area  in  and  south  of  the  village  of 
Bernardston  the  pebbles  are  almost  exclusively  of  the  dark  mica-schist  and 
the  black  argillite  which  occur  wholly  northwest  of  this  point.  This  is 
notably  the  case  in  the  "Bernardston  picnic  grove,"  south  of  the  railroad 
station,  where  is  the  north  end  of  a  continuous  esker  which  extends  a  mile 
or  more  southwest  into  the  Greenfield  basin.  Here  the  pebbles  rarely 
exceed  4  to  6  inches,  and  are  as  finely  worn  into  flattened  discoid  and 
ovoid  forms  as  on  a  sea  beach. 

A  kame  ridge  where  the  road  branches  north,  just  before  it  goes  down 
over  the  bridge  to  enter  Bernardston  village  (opposite  E.  M.  Slate's),  gave 


THE  OLD  COUESE  OF  FALL  KIVER.  621 

this  section:  Coarse  sand  and  gravel,  2  feet;  medium  buff  sand,  4  feet;  fine, 
even-bedded  sand,  5  feet.  Tlie  ridge  was  20  feet  wide  and  the  layers 
crossed  it  horizontally,  as  if  they  had  been  eroded  on  either  side.  A  little 
farther  west,  down  the  hill  toward  the  bridge,  the  gravels  were  found  to  be 
coarse  and  scarcely  bedded  at  all. 

Everything  shows  that  the  floods  swept  west  through  the  Bernardston 
Pass  and,  joined  by  the  waters  coming  down  the  extensive  upper  valley  of 
Fall  River  at  Bernardston  village,  passed  into  the  Greenfield  basin. 

THE   OLD    COURSE   OF   FALL   RIVEK.      ' 

Commencing  high  up  in  the  valley  north  of  Bernardston,  Fall  River 
is  bordered  by  a  broad,  flat  plane  (1  P)  that  has  been  cut  in  a  heavy 
sand  deposit  which  once  filled  the  bottom  of  the  valley,  forming  the 
lake  bench,  and  which  in  part  still  remains  intact  on  either  side  of  the 
alluvial  bottom  of  the  river.  At  the  bridge  in  the  village  of  Bernardston 
this  plain  leaves  the  river  and  skirts  the  west  edge  of  the  kame  area,  being 
bounded  on  the  west  by  West  Mountain,  and  extends  southwesterly  into 
Greenfield,  where  it  merges  with  the  lake  bottom  of  the  Greenfield  basin, 
above  which  the  esker  ridges  project  for  a  distance  and  then  are  finally 
submerged.  The  river,  on  the  other  hand,  does  not  follow  this  lower  plain, 
as  would  seem  natural,  but  runs  from  the  bridge  due  south,  in  a  deep, 
narrow  channel,  cut  in  the  much  higher  kame  area,  and  then  among  the 
drumlins  and  the  sandstone  ridges  to  the  Connecticut. 

It  seems  to  me  certain  that  when  the  waters  of  the  Connecticut  became 
confined  to  the  main  valley  to  the  east,  the  stream  coming  down  the  Ber- 
nardston Valley  continued  to  run  southwestward  by  the  now  abandoned 
channel,  and  cut  down  and  flattened  the  kame  material  into  the  broad,  flat, 
lakelike  watercourse  which  now  remains,  and  which  forms  now,  near  the 
town  line,  a  low  divide  from  which  a  small  brook  runs  back  into  the  main 
stream  and  another  on  to  join  the  Leyden  Brook,  in  the  west  of  Greenfield. 
The  continued  melting  of  the  ice  beneath  the  kame  area  at  last  di-opped 
the  sands  so  low  that  the  stream  suddenly  found  a  new  course  opened  to  it 
directly  south  into  the  Connecticut. 

It  can  be  clearly  proved  that  the  flow  of  the  glacial  waters  in  the 
Bernardston  Valley  commenced  long  before  the  ice  had  lowered  so  far 
that  any  connection  with  the  main  valley  can  have  existed,  for  the  esker  (k) 


622  GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

that  starts  at  the  mouth  of  Fall  River  Valley,  in  the  Bernardston  picnic 
grove,  runs  south,  rising  over  a  col  between  two  drumlins  east  of  the 
road  to  Greenfield,  at  a  much  higher  level  than  the  plain  to  the  west,  here 
described  as  the  old  course  of  Fall  River,  which  was  at  that  time  still  filled 
with  ice.  It  can  be  seen  further  from  this  section  that  the  abundant  flow 
continued  after  the  waters  had  ceased  to  flow  from  the  main  channel 
through  the  Bernardston  Pass.  An  inspection  of  the  map  will  make  it  clear 
that  the  deep  Fall  River  Valley  must  for  a  long  time  have  been  a  main 
artery  of  drainage. 

When  the  waters  went  through  the  Bernardston  Pass  the  ice  had  mostly 
melted  far  north  up  the  main  valley,  but  a  remnant  was  submerged  beneath 
the  sands  along  the  border  of  the  stream  in  West  Northfield,  causing  the 
kettle-holes  of  the  western  border  of  the  Bennetts  Brook  plain  (see  p.  617), 
and  through  the  pass  the  waters  spread  their  gravels  over  a,  considerable 
but  gradually  diminishing  body  of  ice.  At  the  same  time  the  great  volume 
of  water  which  came  down  the  valley  of  Fall  River  also  flowed  over  ice, 
and  thus  were  formed  the  esker  ridges  of  argillite  pebbles  which  project 
out  from  this  valley  and  blend  with  the  gneiss  gravel  brought  through  the 
pass  from  the  main  valley.  A  great  mass  of  ice  filled  the  basin  of  Grill,  and 
thus  completed  the  walls  of  the  pass  and  prevented  the  flood  from  filling 
this  basin,  as  they  naturally  would  have  done. 

When  the  flood  had  so  far  receded  that  the  waters"  of  the  main  stream 
no  longer  went  through  the  pass,  the  waters  of  Fall  River  continued  to 
flow  into  the  Greenfield  basin,  carrying  a  large  volume  of  the  kame  sands 
southward  into  this  area  and  smoothing  out  the  broad  plain  which  still 
extends  between  the  two,  until,  by  the  sinking  of  the  ice,  its  southeastern 
border  was  breached  and  it  found  exit  across  the  kame  gravels  south  into 
the  drift  region  of  Gill  by  way,  apparently,  of  its  reopened  pre-Glacial 
bed. 

THE   BENCH   ON   THE   EAST   SIDE   OF   THE   RIVER   IN   NORTHFIELD   AND   ERVING. 

The  hills  are  set  back  on  the  east  side  of  the  valley  at  about  the  same 
place  as  on  the  west  side,  and  the  high  sands  expand  eastward  across  Hins- 
dale and  the  corner  of  Winchester,  in  New  Hampshire,  up  the  valley  of 
the  large  Perchee  Brook  and  continue  southward  with  a  width  of  200  to 
400  rods  across  Northfield  and.  Erving.     The  rock  surface  is  everywhere 


THE  BENCH  IN  NORTHFIELD  AND  EEVING.  623 

quite  hig'li,  often  up  to  or  iil)ove  the  300-foot  contour,  and  the  layer  of  till 
above  this  is  generally  thin  ami  not  molded  into  drumlins  as  on  the  west 
side.  Hence  the  bench  sands  are  generally  not  of  great  thickness.  They 
repi'csent  mainly  the  deltas  of  Perchee  and  Northtield  brooks. 

At  the  head  of  the  deep  recess  formed  by  the  southwestward  trend  of 
the  valley's  rim  in  the  corner  of  Winchester,  New  Hampshire,  is  the  apex 
of  the  delta  of  Perchee  Brook  (1  s  h,  PL  XXXV,  C),  at  392  feet  above  sea. 
It  consists  of  coarse  deposits,  with  many  rounded  bowlders  of  porphyritic 
granite,  even  up  to  2  or  3  feet  in  diameter.  The  brook  runs  at  the  foot 
of  the  rocky  ridge  nearly  to  the  State  line,  and  all  its  delta  is  on  its  south 
side.  From  its  apex  two  roads  run  toward  Northfield.  The  eastern  runs 
south  at  the  foot  of  the  cliffs  and  marks  the  eastern  shore  iintil,  at  L. 
Lyman's,  it  turns  into  the  plains  toward  Northfield  street.  The  western 
follows  the  brook  until,  just  over  the  State  line,  it  goes  down  from  the 
bench  to  the  next  terrace  level  (1  f)  at  320  feet. 

Between  these  two  roads  runs  a  great  island  of  till  in  the  midst  of  the 
delta  plain.  Just  at  the  foot  of  this  hill,  on  the  side  facing  the  head  of 
the  delta,  is  a  triangular  pond,  800  feet  on  a  side,  depressed  30  feet  below 
the  level  of  the  plain,  its  concave  base  embracing  the  island  and  its  apex 
pointing  toward  the  head  of  the  delta.  From  the  other  end  of  this  island  a 
sandy  esker  ridge  (k)  extends  southwest  for  a  long  distance,  and  just  south 
of  Mr.  D.  L.  Moody!s  main  school  building  a  cutting  showed  about  10  feet 
of  well-sorted  sands;  but  I  was  informed  that  a  little  below  coarse  bowlder 
beds  occur. 

What  is  most  remarkable  in  the  deposits  of  this  delta  and  its  continua- 
tion south  in  the  high  terrace  is  the  great  accumulation  of  fine  sand.  Soon 
after  leaving  the  hills  the  brook  has  cut  deeply  into  these  sands,  and  all  the 
brook  sections  in  the  neighborhood  are  in  like  material.  Following  the 
brook  down  to  where  it  descends  sharply  over  the  rocks  to  the  river  plain, 
these  sands  are  seen  to  rest  on  clay  at  a  height  of  290  feet  above  sea.  Here 
a  line  of  springs  marks  the  base  of  the  sands,  and  immediately  below  aban- 
doned clay  pits  occur,  as  they  do  southward  at  various  lower  jDoints  in  a 
gorge  cut  by  a  tributary  of  this  brook  and  farther  south  by  the  roadside, 
showing  the  clays  to  be  continuous  below  the  level  of  290  feet.  Following 
the  terrace  southward,  shallow  depressions  begin  to  appear  in  it,  and  oppo- 
site the  village  street  it  has  developed  abundant  well-formed  kettle-holes 


624  GEOLOGY  OP  OLD  HAMPSHIRE  COTOTYTlrASS. 


and  is  made  up  of  coarse  gravel,  containing  cobbles  up  to  6  inches  in  length. 
Its  front  edge  has  a  height  of  360  feet  where  it  sinks  down  by  a  steep  scarp 
to  the  level  of  the  Northfield  village  plain  (1  b  t).  At  its  foot  a  brook  runs 
noiihwest  into  the  Connecticut,  which  has  cut  a  notch  in  it,  but  has  made  no 
delta  projecting  out  onto  the  terrace  below,  showing  that  when  it  was  effect- 
ively eroding  the  main  stream  was  also  strongly  eroding,  and  carried  on  all 
its  contributions.  This  is  the  case,  also,  with  all  the  tributaries  down  to 
Millers  Falls. 

South  of  this  brook  the  high  terrace  (1  s  h)  is  continuous,  but  narrows 
rapidly,  and  by  the  side  of  the  road  going  up  to  F.  Johnson's,  just  north 
of  the  single  di'umlin  marked  on  the  map,  a  section  occurs  in  coarse  gravel 
much  contorted.  From  this  point  the  great  sand  masses  of  the  next  lower 
level — the  old  lake  bottom  (1  b  t) — which  are  here  nearly  a  mile  wide  and 
extend  southward  for  over  2  miles  in  the  great  "Beers  Plain,"  have  been 
thi'own  up  in  a  wilderness  of  sand  dunes,  thus  obliterating  almost  all  trace 
of  the  scai-p  which  once  connected  the  two  levels. 

The  plain  of  Northfield  village,  at  the  third  level — 305  feet  (t*) — is 
thinly  covered  with  sand.  Immediately  below  is  till  or  ledge,  but  south- 
ward the  rock  lies  much  lower,  while  the  level  of  300  feet  is  maintained  by 
a  great  volume  of  sands.  Southward  these  sands  rest  upon  finer  material. 
Just  over  the  railroad,  on  the  road  west  from  the  station,  20  feet  of  coarse 
sand,  dipping  S.  20°,  rests  upon  very  fine,  horizontally  bedded  sands  with 
a  single  layer  of  fat  clay  18  inches  thick.  The  former  stratum  was  laid 
down  while  the  stream  was  forming  the  terrace  (t*);  the  lower  is  the 
uneroded  portion  of  the  lake-bottom  beds.  Their  present  eroded  surface 
is  250  feet  above  sea,  and  they  are  exposed  with  a  thickness  of  42  feet,  and 
no  bottom  is  seen;  nor  do  the  sands  vary. 

Just  south  of  the  village  street,  where  two  brooks  come  together  and 
run  under  the  railroad,  the  same  sands  rest,  at  a  height  of  270  feet  above  sea, 
upon  blue  banded  clays,  the  fat  layers  being  one-third  to  two-thirds  of  an 
inch  thick,  and  the  intervening  layers  of  sandy  clay  6  inches  thick.  Four 
miles  farther  south,  at  the  ferry  at  Gill  station,  the  clay  layers  are  one-half 
of  an  inch  wide  and  are  separated  by  layers  of  fine  sand  2  feet  thick. 
Farther  south,  below  Northfield  Farms,  the  Four-mile  Brook  has  cut 
through  heavy  clay  beds  rising  about  260  feet  above  sea. 

The  above  figures  show  that  the  basin  was  filled  up  with  fine  bedded 


THE  MILLERS  EIYER  DELTA.  625 

sands  {intl  clays  to  290  feet  at  its  north  end  and  260  feet  at  its  south  end, 
a  descent  of  30  feet  in  7  miles,  and  the  surface  of  the  liigh  terrace  shows 
about  the  same  descent.  As  this  slope  is  wholly  inconsistent  with  the 
accumulation  of  thick  beds  of  iine  laminated  clays,  some  part  of  this  differ- 
ence may  be  assig'ued  to  a  post-Grlacial  elevation  increasing  northwardly,  of 
which  we  shall  lind  many  other  indications. 

The  order  of  events  in  the  basin  seems  to  have  been,  in  brief,  as  follows: 
The  broad  shoreward  gravels  of  highest  level  began  to  be  brought  into  the 
basin  before  the  last  remnants  of  the  ice  had  been  melted,  those  on  the  west 
side  largely  by  the  main  stream,  those  on  the  east  side  by  the  tributaries. 
Then  far  to  the  south  the  great  delta  of  Millers  River,  as  detailed  below, 
was  thrust  across  the  narrow  outlet  of  the  basin,  ponding  back  the  waters 
and  allowing  the  deposition  of  the  great  thickness  of  fine  sands  and  clays. 
The  coarser  delta  deposits  were  continued  out  over  the  finer,  unconform- 
ably  in  a  sense,  and  completed  the  filling  of  the  valley. 

Where  the  highest  floods  failed  to  plane  the  earlier  beds  down  fully 
they  remain  as  kame  ridges.  When  the  floods  ceased  to  rise  over  these 
highest  flood  plains  before  the  ice  had  wholly  melted  beneath  them  the  latter 
are  kettle-holed. 

THE  MILLEES  KITER  DELTA.   THE  CANYON  AND  OLD  COURSE  OF  THE  CON- 
NECTICUT. 

The  section  of  the  flooded  Connecticut  which  we  have  above  described 
might  very  properly  be  treated  separately  as  the  Northfield  Lake.  It 
would  include  just  that  portion  of  the  valley  which  is  portrayed  on  the 
Warwick  sheet.  The  valley  expands  at  the  north  border  of  this  sheet,  and 
soon  contracts  again  to  the  north  (PI.  XXXV,  C). 

The  high  terrace  which  we  have  followed  south  along  the  east  side  of 
the  valley  as  a  narrow  bench  of  sands  applied  to  the  high,  rocky  valley 
side,  widens  suddenly  south  of  Northfield  Farms,  extends  entirely  across 
the  valley  proper,  and  abuts  on  the  west  against  a  steep  ridge,  called  Mine 
Hill.  The  river  does  not,  as  heretofore,  erode  its  channel  down  the  middle 
of  this  plain,  but  escapes  southwestwardly  from  the  corner  of  the  basin 
tloi'ough  a  deep  gorge  of  its  own  cutting,  between  the  ridge  of  crystalline 
rock  mentioned  above  and  the  Triassic  conglomerate. 

MON  XXIX 40 


626  GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

A  "diy  brook"  has  cut  its  notch  part  way  across  this  plain,  just  west 
of  the  raih'oad,  trying  ineffectually  to  replace  the  river,  and  the  contours 
on  the  north  slope  of  the  plain  bend  south  toward  the  brook  gorge. 

Millers  River,  emerging  from  its  jjortal  in  the  eastern  rock  border  of 
the  valley,  makes  almost  immediately  a  remarkable  curve,  turning  first 
south  and  then  180°  round  through  west  to  north,  and  then  runs  north, 
skirting  the  Mine  Hill  ridge,  to  meet  the  "dry  brook,"  and  then  with  sharp 
western  turn  it  cuts  through  this  I'idge  to  join  the  Connecticut. 

This  is  one  of  the  most  beautiful  spots  in  the  State.  The  Connecticut 
comes  down  from  the  north  in  its  vertical-walled  canyon,  its  waters  foaming 
in  rapids  around  the  great  pudding'-stone  bowlder  amidstream,  still  called 
the  "French  King,"  from  a  tradition  that  in  the  old  French  wars  an  expedi- 
tion dropped  down  the  river  to  this  point  and  a  venturesome  officer  pushed 
his  canoe  to  the  head  of  the  rapids  and  broke  a  bottle  of  wine  on  the  great 
rock,  claiming  the  land  for  the  French  King.  The  broad  stream  then  bends 
sharply  northwest  and  flows  strongly  in  its  deep  gorge,  while  just  at  the 
bend  Millers  River  comes  down  over  the  rocks  in  a  picturesque  fall,  flanked 
by  a  ruined  mill.  The  fall  has  scarcely  worn  back  at  all  from  the  mouth 
of  the  stream,  and  the  whole  impression  is  one  of  recency. 

Looking  down  on  this  Montague  plain  from  one  of  the  high  hills  east 
of  Millers  Falls,  one  easily  restores  the  beds  eroded  by  Millers  River,  and 
then  the  plain  is  seen  to  be  the  northern  j)ortion  of  its  great  delta,  expand- 
ing northward  up  the  narrower  part  of  the  valley  of  the  Connecticut.  In 
following  this  plain  down  from  its  north  end,  opposite  the  point  where  the 
main  stream  enters  its  rocky  gorge,  a  distance  of  about  a  mile,  one  finds 
that  the  sands  grow  coarser  and  coarser  and  grade  into  gravel,  and  opposite 
the  point  where  Millers  River  leaves  its  rocky  canyon  in  the  eastern  wall 
of  the  valley — that  is,  at  the  head  of  the  delta — many  of  the  beds  are  of  very 
coarse  gravel  alternating  with  sand  beds,  showing  the  coarsest  flow-and- 
plunge  structure.  Moreover,  the  plain  slopes  southward  quite  rapidly,  its 
elevation  being  362  feet  north  of  Millers  River  and  350  feet  south,  at  points 
3,000  feet  apart. 

That  the  delta  deposits  of  the  tributary  could  have  been  extended 
north  against  the  current  of  the  main  stream  more  than  a  half  mile  proves 
that  the  current  of  the  main  stream  could  not  have  been  very  strong,  and 
the  southward  slope  of  the  surface  of  the  delta  indicates  that  the  land  was, 
there  relatively  depressed  toward  the  north  and  has  since  risen. 


THE  MILLEKS  RIVEK  DELTA.  627 

From  Xortlitield  Farms  the  Connecticut  River  I'uns  in  a  canyon,  with 
sandstone  on  the  right  ])ank  and  cr3^stanine  rocks  on  the  left,  and  at  the 
moutli  ot'  Jlillers  River  it  tnrns  west  and  northwest  for  about  5  miles 
to  Tiu-uers  Falls,  cutting  off  a  corner  of  the  Grill  sandstone  massif,  and 
then  runs  south,  skirting  the  diabase  ridge  of  Greenfield.  It  thus  gives 
place  for  a  great  ex})ansion  of  the  delta  of  Millers  River,  about  5  miles 
square,  a  broad  elevated  sand  desert — the  Montague  plain — which  on  the 
south  sinks  by  a  marked  delta  front  to  the  low  basin  in  which  lies  the 
■\allasre  of  Montao-ue.  From  Turners  Falls  back  to  the  moiith  of  Millers 
Ri^'er  one  descends  from  the  north  edge  of  this  plain  by  a  single  great 
erosion  scarp  to  the  level  of  the  river,  or  to  the  sandstone  ledges  into  which 
the  stream  has  cut,  thereby  preventing  any  further  erosion  of  the  delta 
beds.  In  all  this  latter  distance  it  formerly  extended  north  across  where 
the  river  now  runs  and  rested  against  the  sandstone,  and  above  Factory 
village  a  broad  remnant  of  it  still  remains ;  and  at  the  mouth  of  Fall  River, 
opposite  Turners  Falls,  it  extended  into  the  basin  of  Greenfield  through 
the  gap  in  the  trap  range,  and  sent  a  large  body  of  sand  by  this  passage 
into  the  Hadley  Lake.  The  river  poured  with  full  current  through  this 
pass,  and  it  must  have  been  a  slight  chance  which  determined  it  in  the 
direction  of  its  present  course  and  prevented  it  from  choosing  a  channel 
down  the  west  side  of  the  trap  ridge  through  Greenfield. 

The  Connecticut  River  was  thus  driven  westward  around  the  great 
delta  and  compelled  to  cut  a  canyon  between  the  sandstone  and  the  crys- 
talline rocks  from  Northfield  Farms  to  the  mouth  of  Millers  River,  and  in 
the  sandstone  on  to  and  beyond  Turners  Flails,  nearly  down  to  the  mouth  of 
the  Deei-field  River. 

The  old  bed  of  the  Connecticut  runs  due  south  from  Northfield  Farms 
past  Millers  Falls,  and  thence  southwest  to  join  its  present  bed  at  the  mouth 
of  Sawmill  River,  in  Montagiie.  This  course  is  marked  by  a  line  of  kettle- 
holes  continued  in  the  channel  of  the  dry  brook  mentioned  above  along  the 
plain  north  of  Millers  River,  by  the  sharp  bend  of  the  latter,  and  by  the 
deep  erosion  basin  that  extends  south  from  it.  Farther  on  it  is  continued  by 
the  line  of  large  kettle-holes  of  which  Green  Pond  and  Lake  Pleasant  are 
the  most  important,  and  by  the  course  of  Pond  Brook  and  Sawmill  River. 

Its  eastern  rocky  border  is  exposed  at  the  falls  which  give  the  name  to 
the  village  of  Millers  Falls,  in  the  north  of  Montague,  and  at  the  bottom  of 
the  deep  cuttings  of  the  railroad  ju.st  below  the  Millers  Falls  station.     The 


628  GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

cuttings  for  the  relocation  of  the  tracks  of  the  raihoad  running  south- 
west from  Millers  Falls  gave  fine  sections  radiating  out  from  the  head  of  the 
delta.  Besides  most  instructive  sections  of  kettle-holes,  described  further 
on,  the  opening  gave  a  fine  view  of  the  whole  structure  of  the  delta  (see 
fig.  41,  p.  668). 

At  a  point  near  where  the  two  raihoads  sejaarate,  the  cutting  was  20 
feet  deep  and  showed  the  sands  resting  on  glaciated  surfaces  of  gneiss 
and  diabase,  without  the  intervention  of  till  or  clays. 

The  section  showed  an  extensive  body  of  sands,  often  exposed  12  to 
16  feet  in  thickness,  and  cross-bedded  in  great  sheets  which  dip  south  away 
from  the  head  of  the  delta  and  represent  the  advancing  front  of  the  latter. 
Above  this  a  horizontal  layer  of  gravel,  averaging  about  3  feet  in  thickness, 
and  diminishing  in  thickness  and  coarseness  outwardly,  made  the  surface. 
This  represents  the  concentration  gravel  manufactured  out  of  the  cross- 
bedded  sands  of  the  delta  by  the  floods  of  the  river  as  they  swept  over  its 
surface  after  its  front  had  passed  farther  outward. 

Where  kettle-holes  had  sunk  dm-ing  the  flood  time,  this  gravel  thickened 
below  to  fill  the  depression,  and  had  plainly  been  pushed  into  the  depres- 
sions from  the  direction  of  the  head  of  the  delta,  the  gravels  being  cross- 
bedded  in  their  thickened  portions,  with  radial  dip. 

All  along  the  eroded  front  of  the  delta  overhanging  Turners  Falls  the 
clays,  resting  directly  on  till  or  sandstone,  rise  to  a  height  of  250  feet  above 
sea  and  are  capped  by  the  delta  sands.  The  clays  have  a  maximum  thick- 
ness of  59  feet  and  are  thin-laminated,  with  the  layers  1  to  1 J  inches  thick. 
The  clays  change  upward  into  the  sands  by  repeated  alternations  of  sand 
and  clay.  At  the  top  of  one  stratum  of  clay  1  foot  thick  a  single  layer  was 
contorted  and  compressed  into  acute  folds  bent  over  southward  and  covered 
by  a  foot  of  sand,  as  if  moved  by  the  friction  of  the  waters  by  which  the 
thick  layer  of  nonlaminated  sand  was  brought  in.  All  above  and  below 
was  undisturbed. 

The  illustration,  fig.  35  (p.  629),  indicates  the  relation  of  the  beds  at 
the  large  brick  pit  south  of  Turners  Falls. 

The  delta  sinks  southward  into  the  deep  land-locked  hollow  in  which 
IS  the  village  of  Montague,  and  along  the  bald  face  of  the  mountain  to  the 
east  of  the  village  the  tei'race  is  represented  only  by  a  narrow  bench  cut  in 
the  till,  and  farther  south  cut  in  the  high  sands  which  fill  the  Mount  Toby 


THE  HADLEY  LAKE. 


629 


e-oro-e.  The  hi>'li  hill  of  sandstono  which  rises  west  of  the  village  is  cou- 
nected  sox;th  with  iMouut  Toby  by  a  sandstone  ridge  at  about  the  height  of 
the  hio'li  tiMTacc,  and  it  is  therefore  certain  that  the  old  bed  of  the  Con- 
necticut can  not  have  gone,  as  an  inspection  of  the  map  would  suggest,  due 
southwest  to  join  the  present  bed  at  the  Sunderland  line.  The  Montague 
depression  may  have  been  eroded  by  the  pre-Glacial  Connecticut  in  a  great 
bend  directed  southward.  It  was  more  probably  cut  out  of  the  soft  sand- 
stone by  the  ice  dividing  on  Mount  Toby. 

Farther  south,  around  the  west  side  of  Mount  Toby,  in  the  narrows 
which  separate  the  Montague  from  the  Hadley  Lake,  as  well  as  along  the 
west  side  of  the  river  from  the  entrance  of  the  gorge  below  Northfield 


Fig.  35— Section  through  the  eroded  front  of  the  great  delta  at  Montague. 

Farms  to  Sugar  Loaf  Mountain,  the  Triassic  rocks  everywhere  approach 
closely  to  the  present  river  and  the  high  terrace  sands  are  preserved  for  the 
most  part  only  in  sheltered  recesses. 

THE  HADLEY  LAKE. 

THE    NOETH    END    OF    THE    LAKE    IN    GREENFIELD   AND    THE     CHANNEL    OF 
CONNECTION   WITH   THE   MAIN   VALLEY. 

In  the  last  chapter  I  have  traced  the  waters  from  the  main  valley 
through  the  Bernardston  Pass  into  the  north  of  Greenfield,  where,  at  the 
flood  time,  they  widened  somewhat  into  a  small  temporary  lake,  whose 
outlines,  as  it  extended  west  across  the  town,  are  indicated  on  the  map  by 
the  extent  of  the  colors  marked  1  s  h  and  If,  where  they  are  drained  by  the 
three  branches  of  Mill  Brook. 

After  the  waters  had  ceased  to  flow  across  from  the  main  valley  an 
abundant  supply  still  came  down  the  valley  of  Fall  River  and  pushed  out 
into  this  Greenfield  Lake  a  marked  delta,  and  the  broad  bottom  of  this 


630  GEOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 

stream  with  its  delta  is  marked  on  the  map  (1  f  ^)  by  a  color  different  from 
that  devoted  to  the  lake  bottom.  The  progress  of  this  delta  was  arrested 
(as  detailed  under  a  preceding  heading,  p.  621)  by  the  breaching  of  the  high 
terrace  sands  and  the  passage  of  the  Fall  River  south  to  the  Connecticut. 
Clay  (1  b  c)  appears  at  the  surface  of  the  lake  bottom  at  one  place,  back  of 
the  schoolhouse,  near  the  residence  of  A.  Graves.  It  is  abundant  and  is 
the  only  occurrence  in  this  area. 

THE   GREEN  BIVEE   GLACIEB. 

High  ground  borders  Greenfield  north  and  west.  In  the  eastern  half  of 
the  town  all  depressions  are  filled  with  flood  sands,  which  we  have  traced 
into  the  area  through  the  Bernardston  and  the  Fall  River  passes.  The 
western  half  is  a  deeply  sunken  area.  The  two  bodies  of  sand  noted  above 
expand  westwardly,  wrapping  around  French  HilP  on  the  north  and  south, 
and  end  very  strangely  on  the  west  in  a  high  bluff  which  overlooks  the 
broad,  low  basin  of  Green  River  and  Glen  Brook. 

One  goes  down  from  the  edge  of  this  bluff  by  a  steep  scarp  60  feet  to 
the  bottom  of  the  basin,  and  neither  the  scarp  nor  this  broad  bottom  seem 
to  me  to  be  the  work  of  Mill  River,  which  now  flows  in  it,  bounded  on 
either  side  by  its  own  alluvial  bottom  and  terraces. 

This  valley,  which  I  believe  to  have  been  filled  with  ice  while  the  lake 
deposits  were  gathering,  stretches  along  the  whole  west  side  of  Greenfield. 
Not  only  is  the  mass  of  sand  which  must  have  been  removed,  if  this  basin 
had  been  filled  up  at  the  flood  time,  out  of  all  proportion  to  the  amount 
of  work  done  by  the  other  streams  in  the  terrace  period,  but  the  bottom  of 
the  basin  and  its  eastern  scarp  is  an  irregular,  kamy,  kettle-holed  surface, 
entirely  unlike  the  surface  of  the  erosion  terraces  of  this  and  the  other  tribu- 
taries of  the  Connecticut;  and  the  true  terraces  which  border  the  stream,  cut 
at  and  below  the  level  of  this  broad,  irregular  bottom,  correspond  in  number 
and  extent  with  those  of  the  other  streams. 

Again,  on  the  west  the  rocky  and  till-covered  border  of  this  basin  slopes 
rapidly  to  its  bottom,  and  opposite  each  valley  notch  a  great  delta  heading  at 
a  level  but  little  below  that  of  the  high  terrace,  and  with  its  semicircular  front 
untouched  by  erosion,  is  thrust  far  out  into  the  basin,  showing  conclusively 

'  The  hill  500  feet  high  in  the  north  part,  just  east  of  the  railroad. 


THE  GREEN  KIVER  GLACIER. 


631 


that  the  bottom  of  tlie  basin  and  these  high  deltas  were  formed  at  the  same 
time,  whifli  must  have  been  near  the  end  of  the  time  of  the  high  water 
stand,  wlien  the  ice  had  finally  melted  after  having  prevented  the  filling  of 
the  valley.  The  dissected  delta  of  the  Green  River  itself  where  it  leaves  its 
rocky  gorge  and  enters  the  basin  is  shown  in  fig.  3G. 

But  one  traces  with  great  clearness  the  broad  watercourse,  with  its 
abundant  sands,  fi-om  Bernardston  across  the  north  of  Greenfield  to  where 
the  extended  sand  flats  end  suddenl}^  and  sink  by  a  great,  irregular  scarp 
into  this  basin,  and  a  little  farther  south  the  similar  watercourse  from 
Factory  Village,  near  Turners  Falls,  passes  across  the  middle  of  Greenfield, 
and  stands  in  the  same  relation  to  the  southern  part  of  this  deep  elongate 
depression.     It  must  thus  have  been  filled  had  it  stood  empty  in  the  way 


~^S  FEET        - 


FI8. 36.— Section  of  the  Green  Eiver  delta  at  the  north  end  of  the  Green  Elver  basin,  where  the  stream  comes  out  of  its  rocky 
canyon,  showing  that  the  delta  was  sent  but  little  into  the  lake,  and  its  front  not  eroded. 

of  these  two  abundant  streams,  and  I  can  therefore  only  suppose  that 
here,  in  the  northwest  corner  of  the  valley  of  the  Connecticut,  and  in 
this  long  depression  between  the  mica-schist  mass  of  Charlemont  and  the 
red  sandstone,  a  lobe  of  the  ice,  sent  down  the  Green  River  Valley  from 
the  high  ground  in  Leyden  across  the  whole  length  of  Greenfield,  lingered 
till  after  the  floods  had  ceased  to  come  through  the  two  passes  mentioned 
above,  and  after  Fall  River  had  ceased  to  flow  west  into  the  Greenfield  Lake. 
I  do  not  think  that  the  ice  stood  high  above  the  level  of  the  flood  waters 
in  the  flood  time ;  but,  like  the  great  bodies  of  ice  described  by  Dall  in 
Alaska,  it  was  submerged  beneath  the  sands  as  a  great  continuous  body 
filling  the  valley  and,  on  melting,  allowing  its  load  of  sands  to  drop  about 
50  feet  to  their  present  position. 


632  GEOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 

THE   FACTORY  VILLAGE    CHANNEL. 

The  map  shows  very  clearly  the  broad  watercourse  which  bends  north 
from  Turners  Falls  and  then  turns  sharply  southwest  and  runs,  its  banks 
and  bottoms  well  preserved  and  uneroded,  to  where  it  widens  out  into  the 
broader  sand  plain  of  the  south  part  of  Grreenfield. 

This  passageway  was  set  free  by  the  ice  earlier  and  was  occupied  by 
the  Connecticut  longer  than  the  passage  farther  north  through  the  Ber- 
nardston  Pass,  and  a  vastly  greater  body  of  material  was  brought  into  the 
Deerfield  side  valley  by  this  way  than  by  the  northern  one. 

THE    HIGH    TERRACE    PLAINS    IN    THE    SOUTH    OF    GREENFIELD    AND   NORTH   OP 

DEERFIELD, 

At  the  end  of  the  Champlain  period  a  broad  unbroken  plain  extended 
from  the  south  part  of  Greenfield  southward  through  Deerfield,  out  of  which 
the  channel  of  Green  River  and  the  great  basin  of  the  Deerfield  River  have 
been  eroded.  Tlu-ough  the  southern  part  of  Greenfield  and  the  north  of 
Deerfield,  to  near  the  point  where  the  Deerfield  River  leaves  its  rocky 
gorge,  the  deposits  forming  this  plain  are  laminated  clays,  often  20  to  33 
feet  thick,  overlain  by  sands  reacliing  a  thickness  of  80  feet,  often  hori- 
zontally laminated  in  their  lower  portions  and  cross-bedded  on  a  grand 
scale  above. 

The  section  exposed  on  the  south  side  of  the  road  from  Greenfield 
to  Franklin  Park,^  in  the  hillside  immediately  beyond  the  bridge,  is  very 
striking.  In  the  bed  of  the  brook  the  reefs  of  bright-red  sandstone  rise 
above  the  water  and  run  under  the  bank.  On  this,  in  the  vertical  wall  facing 
the  stream,  is  exposed  20  feet  of  till,  dull  red  and  made  almost  entu-ely  of 
comminuted  sandstone.  This  is  covered  by  20  feet  of  horizontally  bedded 
clay,  in  layers  1  inch  thick  on  an  average,  and  as  one  goes  up  the  hillside 
the  clays  are  seen  to  be  capped  by  a  great  thickness  of  fine  sands,  hori- 
zontally and  distinctly  laminated,  at  least  55  feet  thick.  The  upper  20  feet 
is  made  up  of  sands  with  flow-and-plunge  structure  and  cross-bedding  on  a 
grand  scale.  The  section  is  exposed  for  200  feet,  and  the  sands  dip  with 
varying  and  suddenly-changing  angle  0-30°,  always  toward  the  east. 
These  latter  sands  vary  from  fine  to  coarse. 

■  '■  The  luroad,  perfect  plain  (1  s  h)  south. west  of  Greenfield  and  extending  to  the  Deerfield  River. 


THE  HIGH  TERRACE  IN  GREENFIELD.  633 

West  across  the  high  plain  (Fraukhn  Park),  from  the  top  of  tliis  sec- 
tion to  where  the  raih-oad  again  cuts  into  it,  the  sands  rise  in  heavy  beds 
h\  a  long  and  slightly  cni'ved  sweep  from  north  to  south.  These  two  sec- 
tions lie  just  south  of  the  south  end  of  the  great  Green  River  depression 
mentioned  above.  To  the  west  the  wall  rises  unbroken,  and  there  is  no 
channel  down  which  a  considerable  stream  could  have  come. 

It  seems  to  mo  that  the  sands  have  here  been  built  up  to  this  high  level 
by  the  water  from  the  Bernardston  Pass  and  Factory  village  channel 
coming  down  over  the  ice  which  filled  the  Green  River  basin.  It  is  difficult 
to  see  how  they  can  have  come  from  aay  other  direction,  and  equally  diffi- 
cult to  see  how  they  can  have  been  built  up  here  to  a  broad  plain  of  the 
height  of  the  high  terrace  while  the  above  basin. remained  open  and  unfilled 
to  the  north. 

The  clays  appear  abundantly  in  the  south  half  of  Greenfield,  Avhere 
they  are  used  for  brick  making,  and  rest  on  sandstone  or  till.  Farther  south, 
in  the  southwest  corner  of  the  Deerfield  River  basin,  where  a  brook  has  cut 
back  in  the  rim  of  the  basin,  is  a  great  exposure  of  these  clays,  which  for 
a  distance  of  about  12  feet  down  from  the  surface  and  about  the  same  in 
from  the  basset  edges  of  the  horizontal  beds,  have  weathered  to  fine  buff 
clays,  while  the  interior  is  the  ordinary  blue  clay. 

Farther  south  the  upper  surface  of  the  clays  is  marked  for  a  long  dis- 
tance by  a  line  of  springs  in  the  bluffs  along  the  west  side  of  the  basin. 
Before  reaching  the  mouth  of  the  gorge  of  the  Deerfield  River,  however, 
the  clays  change  into  fine  sands,  and  the  upper  sands  also  grow  finer,  and  in 
the  southern  bluffs  of  the  erosion  basin  the  whole  thickness  of  the  old  delta 
of  the  Deerfield  River  is  made  up  as  illustrated  in  the  Wapping  cutting  (see 
PI.  XVIII,  p.  694)  by  50  feet  of  the  very  finest  sands,  and  this  continues 
to  be  the  character  of  the  great  body  of  sands  which  fill  the  Deerfield 
Valley  south  through  Deerfield  and  Hatfield. 

It  seems  probable  that  the  delta  of  Deerfield  River  was  thrust  across 
the  valley  to  abut  against  Deerfield  Mountain  upon  the  east,  and  was 
elevated  more  rapidly  than  the  deposits  to  the  north  in  Cheapside  and 
Greenfield,  so  that  a  quiet  area  of  deeper  waters  existed  here,  in  which  the 
clays  were  laid  down;  and  later,  the  current  increasing,  the  horizontal 
sands  were  carried  in  over  them,  probably  through  the  pass  from  Turners 
Falls;  and  at  last  the  heavy  floods  of  the  hightest  water  stand  through  the 


634  GEOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 

Beruardstoii  Pass  and  across  the  north  of  Greenfield  brought  the  coarser 
sands  down  over  the  Grreen  River  glacier  and  spread  them  to  build  up  the 
broad  plain  of  Franklin  Park 

THE   LAKE   BENCH   FROM  DEEKPIELD   EIVER   SOUTH. 
THE   DEERFIELD   DELTA. 

South  of  the  erosion  basin  of  Deerfield  River  the  bench  (1  s  h)  consists 
of  the  southern  half  of  the  great  delta  of  the  Deerfield — that  portion  which 
has  escaped  the  later  erosion  of  the  river  itself.  It  spreads  out,  fanlike,  as 
a  broad,  flat  alluvial  cone  from  the  mouth  of  the  rocky  canyon  of  the 
Deerfield,  where  it  has  an  elevation  of  320  feet,  and  slopes  very  gradu- 
ally to  its  front  edge,  which  is  about  30  feet  above  the  lake  bottom,  and 
then  drops  by  a  steeper  grade  to  the  level  of  the  latter.  Its  outer 
boundary  is  in  places  not  sharply  marked,  as  broad  bars  molded  by  the 
current  of  the  main  valley  from  the  abimdant  detritus  furnished  by  the 
Deerfield  are  spread  in  front  of  it  and  render  the  lake  bottom  unusually 
irregular.  A  cutting  of  the  Canal  Railroad,  18  feet  deep,  passing  from  the 
outer  border  directly  to  the  apex  of  the  cone  above  Stillwater  bridge, 
showed  in  beautiful  detail  the  whole  structure  of  the  broad  delta.  It  is 
made  up  entirely  of  well-washed  sands,  everywhere  coarser  above  and  finer 
below.  The  upper  layer  varies  from  3  to  7  feet,  and  is  made  u;p  of  coarse 
sand  and  fine  gravel,  well  washed  and  rounded,  laid  down  in  broad,  lentic- 
ular layers,  as  a  whole  horizontal  or  conforming  to  the  slight  slope  of  the 
surface.  Below  are  fine,  whitish,  perfectly  sorted  sands  in  two  grades,  fine 
and  very  fine.  The  former  are  thrown  down  in  layers  1  to  2  feet  thick, 
with  delicate  flow-and-plunge  structure,  and  dipping  at  all  angles  up  to 
30°  SE. — that  is,  radially  from  the  old  mouth  of  the  river.  These  layers 
are  separated  by  other  layers,  from  2  to  8  inches  thick,  of  the  very  fine, 
moist,  compact,  almost  clayey  sand,  which  are  thrown  down  upon  rippled 
surfaces  of  the  coarser,  and  show  a  flow-and-plunge  structure  of  extreme 
delicacy. 

In  an  exceptional  case  a  layer  of  the  very  fine  sand  occurs  a  mile 
out  in  the  valley,  dipping  15°  SE.,  which,  although  bounded  for  a  long 
distance  above  and  below  by  horizontal  surfaces  and  contained  in  undis- 
turbed layers  of  the  coarser  sand,  is  contorted  in  a  very  complex  way,  and 


TUE  WEST  BKOOK  DELTA.  635 

thin  layers  of  a  coarser  saiul  included  Avithin  it  are  so  twisted  into  the  mass 
that  they  can  be  followed  for  only  a  short  distance. 

A  mile  south,  in  the  Northampton  quadrang-le,  in  the  delta  at  the  road 
south  from  Mill  River  village,  where  Bloody  Brook  joins  Mill  River,  I 
found  in  the  same  })Osition  a  layer  identical  with  this  in  all  respects,  and 
it  may  be  continuous  between  the  two  places,  and  represent  a  time  when 
the  river  was  clog'g'ed  with  ice,  so  that  its  current  was  stopped  and  an 
unwonted  thickness  of  the  very  fine  sands  deposited  and  thrown  into  confu- 
sion by  the  stranded  ice.  The  layer  resembles  so  exactly  the  thicker  one 
described  from  the  Wapping  cutting  (PI.  XVIII,  p.  694)  that  one  diagram 
would  serve  for  both. 

Farther  out,  near  the  outer  edge  of  the  bar,  the  coarse  sand  and 
gravel  layers  thicken  downward  and  pitch  sharply  southeast  in  broad, 
cross-laminated  layers,  and  the  finer  sands  have  disappeared  or  gone  below 
the  level  of  the  cutting.  It  is  plain  that  these  latter,  which  lie  below  and 
continue  everywhere  below  the  level  of  the  railroad  certainly  for  many 
feet,  represent  the  front  of  the  delta  as  it  was  pushed  out  into  deep  water 
Their  varying  dip  corresponds  to  the  varying  slope  of  the  face  of  the  delta, 
and  I  am  inclined  to  believe  that  the  thick  layers  of  fine  sand  (1  to  2  feet) 
represent  the  product  of  a  single  flood,  upon  whose  rippled  surface  rests  in 
each  case  the  finer  deposit  of  the  succeeding  winter. 

The  front  of  the  delta  narrows  southward  and  is  continuous,  at  the 
same  level,  with  the  delta,  also  very  large,  of  Mill  River,  upon  which  is  the 
village  of  the  same  name.  This  is  more  complete,  though  Mill  River 
escapes  through  it  in  a  broad,  low  plain  of  erosion,  and  skirts  the  hill  for  a 
long  distance  south.  Then,  for  a  still  longer  distance  south,  across  the  line 
into  Whately,  the  bench  is  wholly  wanting.  At  present  the  broad  lake- 
bottom  plain  stretching  across  from  South  Deerfield  abuts  against  the  steep 
cliffs  with  no  change  of  level. 

THE  WEST   BROOK   DELTA. 

From  Roaring  Brook  down  through  Whately  the  hills  have  an  easier 
slope  and  were  covered  with  much  drift  material,  out  of  which  the  waters 
have  formed  an  irregular  bench,  which  is  only  in  part  built  up  to  true  level. 
This  continues  almost  to  the  south  line  of  Whately,  where,  near  West 
Brook,  the  bench  (1  s  h)  is  again  well  developed  and  is  very  complicated  and 


636  GEOLOGY  OF  OLD  HAMPSHIRE  COUJ^TY,  MASS. 

interesting.  Long  before  reaching  the  brook  it  rises  to  the  height  of  318 
feet  and  widens  rapidly  into  a  broad  sand  plain,  across  which  the  brook, 
emerging  from  the  high  lands  at  the  road  crossing  near  a  magnificent 
drumlin  (called  Belmont)  that  rises  on  the  north  a  hundred  feet  above  the 
plain,  runs,  over  a  bed  of  coarse  gravel  which  is  very  little  lower  than  the 
surrounding  level,  and  at  the  front  of  the  plain  falls  rapidly  over  a  reef  of 
compact  hornblendic  granite  (tonalite)  into  the  valley  below.  Just  south 
this  reef  rises  in  a  narrow  ridge  and  runs  parallel  to  and  about  half  a  mile 
distant  from  the  western  rim  of  the  valley,  southward  through  Hatfield,  to 
end  in  Elizabeth  Rock  in  Northampton.  At  the  highest  water  stand  it  was 
a  long  island  in  the  lake,  or  rather  two  islands,  as  it  is  broken  through  at 
a  point  in  the  middle  of  its  length,  tlu-ough  which  the  "Running  Grutter" 
enters  the  main  valley.  Into  this  lateral  valley  the  waters  of  West  Brook 
carried  the  greater  part  of  the  detritus  they  were  bringing  down,  and  the 
plain  we  are  following  continues  at  the  same  high  level,  quite  even  and 
sandy,  for  a  mile  farther  south,  bounded  on  the  west  by  the  steep,  rocky 
rim  of  the  valley  and  on  the  east  by  this  island;  and  from  the  south  the 
sands  of  the  high  bench  in  Northampton  enter  the  side  valley  west  of 
Elizabeth  Rock  and  pass  up  it  for  almost  the  same  distance,  while  outside, 
on  the  east  of  the  rocky  island  which  is  called  "'The  Rocks,"  in  Hatfield, 
the  fine  sands  of  the  broad  lake  bottom  (1  b  t)  abut  at  a  much  lower  level 
directly  against  the  bare  cliffs. 

On  the  shrinking  of  the  flood  waters  A^est  Brook  found  its  way,  not 
down  the  western  side  trough  into  which  nearly  all  its  sands  had  been 
carried,  but,  like  so  many  other  streams  in  the  valley,  by  a  detour  to  the 
north  around  the  north  end  of  the  granite  ridge.  In  a  similar  way  Broad 
Brook,  which  heads  in  the  broad  sand  plain  north  of  Florence,  runs  a  long 
way  north  up  the  trough  we  have  just  followed  south,  and  breaks  through 
"  The  Rocks"  in  the  center  of  the  ridge  to  join  the  main  valley,  searching 
out  for  itself  the  most  northerly  outlet  possible. 

This  is  sufficiently  explained  by  supposing  that  the  current  of  the 
stream,  combined  with  that  of  the  main  stream,  kept  the  sands  at  a  slightl}^ 
lower  level  opposite  its  mouth  than  lower  down,  where  they  were  spread 
in  the  long  trough  of  quieter  waters,  so  that  on  the  lowering  of  the  water  in 
the  main  valley  the  tributary  found  its  way  through  lower  ground  around  to 
the  north  of  the  bar;  still,  the  many  times  this  occurs  in  the  valley,  under 


THE  MILL  RIVER  DELTA.  637 

various  circumstances,  points  to  a  cuiumon  cause,  and  is,  I  think,  connected 
with  the  lowering  of  the  upi)er  portion  of  tlie  valley,  thus  lessening  the 
pitch  to  the  southward.  Brooks  from  the  north  and  south  now  join  and 
break  through  the  barrier  near  the  south  line  of  Hatfield,  and  have  carried 
out  much  of  the  sand,  so  that  one  can  not  decide  whether  the  high  sands 
formerly  filled  it  entirely.  It  is  certain  that  the  sands  of  West  Brook 
spread  very  slowly  southward,  and  that  the  waters  entering  by  the  central 
break  in  the  ridge  spread  north  and  south,  throwing  down  clays  up  to  high 
level,  and  that  the  high  delta  sands  encroached  upon  them  from  the  north  as 
the  growth  of  the  delta  went  on. 

THE  MILL  RIVER  DELTA  IN  NORTHAMPTON. 

Farther  south,  on  the  north  line  of  Northampton,  the  western  rim  of 
the  valley,  which  has  come  down  southward  from  the  northwest  corner  of 
Greenfield,  swings  southwestward  and  runs  back  of  Florence,  by  the  bridge 
at  Leeds,  to  Loudville,  where  it  turns  at  right  angles  and  runs  for  two  miles 
southeast  before  it  regains  its  southward  course.  The  bay  thus  formed  was 
studded  with  a  great  number  of  islands,  all  of  till,  for  the  rocky  floor  lies 
everywhere  deep  below  the  surface.  They  are  the  drumhns  already 
described.  Into  this  bay  flowed  the  waters  of  four  large  streams,  two  of 
which  are  dignified  by  the  name  of  river,  and  they,  together,  filled  the  bay 
and  sent  great  quantities  of  detritus  out  into  the  valley,  to  be  carried  south- 
ward by  the  main  stream. 

Their  common  delta  has  been  greatly  cut  away  by  the  streams  them- 
selves in  their  subsequent  oscillations-  as  they  followed  the  margin  of  the 
great  river  downward  during  the  period  of  shrinkage,  and  one  must  know 
the  country  well  and  draw  much  on  the  imagination  to  reconstruct  the  broad 
plain  as  it  formerly  spread  across  from  Elizabeth  Rock  to  Loudville  and  out 
from  Leeds  to  the  border  of  the  Meadows.  Mill  River  has  been  espe- 
cially destructive,  and,  as  its  mouth  advanced  from  Leeds  to  its  present 
place,  it  has  worn  out  all  the  broad  basin  in  which  it  flows,  and  its  tribu- 
taries have  cut  out  the  pecuHar  depression  of  the  "  Bay  State."  One  must 
think  of  all  this  area  raised  to  the  level  of  and  merged  into  the  Florence 
plain  in  order  to  reconstruct  this,  by  far  the  largest  delta  deposit  of  the  high 
bench  upon  the  west  side  of  the  river. 

Along  the  road  from  Florence  to  West  Farms,  and  then  to  Loudville, 
one  rides  for  several  miles  over  a  sand  plain  (1  s  h)  about  305  feet  above  sea, 


638  GEOLOGY  OF  OLD  HAMPSHIEE  COUISTTY,  MASS. 

abutting  against  the  cliffs  on  the  northwest.  Its  border  against  the  granite 
bluffs  is  exceptionally  well  preserved,  but  in  places  is  deeply  kettle-holed 
in  the  portions  adjoining  the  rocks.  It  stretches,  except  where  interrupted 
by  drift  islands,  with  gentle  slope  southward  for  a  long  distance,  to  descend 
at  last  more  abruptly  to  the  village  of  Easthampton,  its  scarp  being  ter- 
raced, but  apparently  not  much  cut  back,  while  in  Northampton  it  has 
suffered  much  more  serious  erosion  during  the  formation  of  the  lower 
ten-aces. 

The  apex  of  the  delta  of  Mill  River  in  Northampton  is  where  the  bridge 
crosses  the  rocky  bed  of  the  stream  before  entering  Leeds.  It  widens  sud- 
denly at  Florence.  Its  extent,  apparently  out  of  proportion  to  the  drainage 
area  of  Mill  River  and  the  other  streams  that  formed  it,  is  due  lai'gely  to 
the  fact  that  its  sands  are  spread  out  among  the  lenticular  drift  hills  by 
which  the  great  bay  in  the  crystalline  rocks  was  filled.     (See  p.  643.) 

The  cutting  along  the  New  Haven  and  Northampton  Railroad  made  to 
obtain  material  for  raising  the  railroads  through  Northampton  gave  repeated 
sections  north  of  the  railroad,  extending  from  the  brook  crossing  east  of 
Florence  to  the  crossroads  next  east,  a  distance  of  a  quarter  of  a  mile. 
In  all  the  western  part  of  this  section  (which  runs  east  and  west)  the  sands 
are  cross-bedded  on  the  grandest  scale,  the  layers  in  the  long  cut,  which 
was  15  feet  high,  having  a  uniform  and  high  westerly  dip.  In  two  cases 
the  material  suddenly  grew  fine,  and  heavy  clayey  layers  are  intercalated 
in  the  coarse  buff  to  reddish  sands.  In  the  eastern  portion  of  the  section — 
the  part  south  of  the  cemetery — the  beds  bend  over  and  dip  east,  and 
are  here  greatly  disturbed  and  mixed  with  glacial  material  by  stranded 
glacial  ice. 

An  inspection  of  the  map  will  show  that  the  long  drumlin  called 
Strawberry  Hill,  just  north  of  Florence,  and  the  prominent  drumlin  north  of 
the  Bay  State,  nearly  cut  off  this  area  from  direct  communication  with  the 
waters  coming  out  of  the  Mill  River  gorge,  and  that  these  cross-bedded 
sands  must  have  grown  as  a  broad  sand  spit  extending  south  from  Fortifi- 
cation Hill  to  the  north  and  made  up  of  -material  swept  south  across  the 
Camp  Meeting  grounds  and  around  the  east  side  of  this  hill,  so  that  they 
were  thrown  down  with  strong  westward  dip  on  the  inner  (western)  and 
sheltered  side  of  this  bar,  along  the  outer  side  of  which  the  icebergs 
stranded. 


TUE  MILL  RIVER  DELTA.  639 

The  southern  portion  of  the  delta  is  composed  of  the  confluent 
deposits  of  ]\Iill  Kiver  and  the  north  branch  of  the  Manhan.  The  great 
•ilacial  lake  in  Westhanipton  (p.  594)  served  as  a  catchment  basin  for 
sands  which  were  carried  ultimately  by  Roberts  Meadow  Brook  and  the 
Manhan  to  augment  the  high  terrace  at  this  point.  While  the  sands  in 
Northampton  are  in  many  beds  clear  gray,  showing  under  the  micro- 
scope many  rounded  grains  of  black  mica-schists  like  those  of  Goshen 
and  Chesterfield,  in  others  they  are  reddish  from  the  abundance  of  garnet 
grains  in  them,  both  peculiarities  indicating  their  origin  from  the  garnetif- 
erous  mica-schists  in  the  drainage  area  of  Mill  River.  The  sands  of  the 
southern  portion  of  the  plain  are  more  largely  granitic  and  are  derived  from 
the  great  granitic  area  of  Westhampton.  This  may  be  taken  as  one  of  the 
jDroofs  of  the  assertion  that  the  high  terrace  was  mainly  brought  in  from  the 
sides  of  the  basin.  The  great  sand  plain  is  continued  across  to  the  North 
Branch,  is  in  all  this  distance  more  than  a  mile  wide,  and  sinks  in  several 
great  terraces  to  the  clayey  lake  bottom  at  Easthampton,  and  as  it  nears 
the  south  line  of  Southampton  it  enters  the  western  of  the  three  passages 
by  wliich  the  waters  passed  out  upon  the  Westfield  plain,  and  just  on  the 
town  line  it  received  the  abundant  deposits  of  the  southwest  branch  of  the 
Manhan  at  Russellville,  and  across  the  basin  since  eroded  by  this  stream 
it  was  plainly  continuous  with  the  north  end  of  the  Westfield  plain. 

Just  where  the  western  channel  widens  by  the  dropping  down  of  the 
hill  east  of  East  Farms  into  this  broad,  open  plain  the  abundant  contribu- 
tions of  the  branch  of  the  Manhan  last  mentioned  were  received  and  spread 
clear  across  the  channel,  up  nearly  to  the  normal  high  terrace  level — the 
deep  water  of  the  lake  bottom  shallowing  southward  in  the  channel  and 
coming  to  an  end  just  opposite  the  mouth  of  the  branch,  and  marking  out 
thus  the  channel  whereby,  on  the  recession  of  the  waters,  the  Manhan  was 
compelled  to  take  a  course  north  across  Southampton  and  Easthampton  to 
join  the  Connecticut  at  the  head  of  the  oxbow. 

THE  LAKE  BENCH  ON  THE  EAST  SIDE  OP  THE  HADLEY  LAKE  IN  LBVERETT  AND 

AMHERST. 

Through  the  Narrows  in  Sunderland  the  bench  (Ish)  is  well  marked 
along  the  west  slope  of  Mount  Toby,  and  turning  the  corner  of  the  mountain 
it  rests  against  its  south  side.  It  is  characterized  by  fine  sands  in  great 
quantity,  dependent  upon  the  fact  that  the  region  is  far  from  the  mouth  of 


640       GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

any  river,  the  sands  having  been  carried  a  great  distance  by  the  main 
stream.  Against  the  north  end  of  Smiderland  street  it  is  represented  by  a 
horizontal  shelf  cnt  in  the  sandstone.  The  terrace  then  widens  in  the 
extensive  plain  of  South  Leverett  which  rests  against  the  sandstone  moun- 
tain on  the  west  and  against  the  crystalline  rocks  on  the  east,  and  runs  up 
into  the  gorge  on  the  east  side  of  Mount  Toby.  At  its  head,  near  the  rail- 
road-crossing north  of  the  station,  it  is  a  coarse  gravel  with  pebbles  6  inches 
in  diameter,  and  it  has  a  height  here  of  310  feet  above  sea.  It  slopes 
gently  to  "its  front,  where  it  has  a  height  of  290  feet  above  sea,  and  is  made 
up  of  coarse  sand. 

By  recurring  to  the  description  of  the  old  course  of  the  Locks  Pond 
Brook  down  through  the  Mount  Toby  gorge  to  empty  into  the  Hadley 
Lake  at  this  point  (see  p.  584)  when  the  ice  still  filled  the  Montague  basin 
to  the  north,  the  reader  will  understand  my  conclusion  that  the  main  por- 
tion of  the  great  mass  of  gravel  gathered  here  was  swept  into  its  place  by 
the  Locks  Pond  Brook,  deflected  soiithward,  and  only  smoothed  down  to 
its  present  level  by  the  waters  of  the  Hadley  Lake.  1  imagine  that  this 
deflection  of  the  brook  by  ice  filling  the  Montague  basin  may  have  taken 
place  when  the  ice  had  abandoned  all  the  Hadley  Lake  except  its  northern 
lobe  in  Greenfield. 

Southward,  the  high  terrace  is  only  indistinctly  marked  against  the  till 
for  a  long  distance,  as  no  brooks  brought  in  material  here. 

THE    DELTA    OF    CUSHMANS    BROOK    AT    NORTH    AMHEKST  AND    THE    ISOLATION    OP    THE    EAST    STBEBT 

BASIN  IN  AMHEKST. 

On  reaching  North  Amherst  we  find  the  high  terrace  (1  s  h)  developed  in 
great  force  and,  because  of  the  rising  of  the  block  of  hills  north  of  Amherst 
Center  as  a  great  island  in  the  lake,  with  considerable  complexity. 

A  great  depression,  closed  on  all  sides,  extends  along  the  eastern  line 
of  Amherst,  ending  on  the  south  at  Dwight's  station,  having  the  village  of 
East  Street  in  its  center  and  being  bounded  on  the  north  by  the  delta  of 
Cushmans  Brook. 

It  is  plain  that  when  Cushmans  Brook  began  to  flow  into  the  lake 
there  was  free  communication  between  this  depression  and  the  main  area 
of  the  lake  to  the  west,  across  the  space  now  occupied  by  the  delta,  and 
that  for  a  time  the  sands  brought  in  by  the  brook  were  swept  southward 


KENCH  SUKROUNDING  BAST  STREET  BASIN.  641 

al.ni-;'  the  west  slope  of  the  I'elhaiu  Hills,  forming  the  extensive  sand 
deposits  which  flank  these  hills  for  a  long  way  south.  At  last,  however, 
the  delta  extended  across  to  the  rocky  hill  north  of  the  North  Amherst 
cemetery  and  excluded  the  main  current  from  this  eastern  basin,  and  from 
this  time  on  the  sands  of  Cushmans  Bi-ook  were  swept  around  west  of  the 
Mount  Pleasant  block  of  hills,  building  up  a  great  terrace,  or  rather  sand 
bar,  which  extends  south  to  the  Agricultural  College.  The  college  build- 
ino-s  stand  on  it,  and  it  ends  at  the  south  border  of  the  college  farm. 

THE  BENCH  SURROUNDING  THE  EAST   STREET  BASIN. 

By  the  extension  of  the  delta  of  Cushmans  Brook  across  the  north  end 
of  this  basin  a  separate  body  of  water  resulted,  connected  with  the  main 
lake  only  by  narrow  channels  among  the  drift  hills  south  of  Amherst 
Center. 

The  hiffh  terrace,  continuous  southward  from  the  extended  delta  flat 
at  North  Amherst  City  along  the  flank  of  the  Pelham  Hills,  is  a  marked 
object  from  College  Hill.  It  appears  here,  as  around  much  of  the  valley, 
as  the  highest  line  of  cultivation,  and  above  this  horizontal  line  the  hillside 
is  heavily  wooded.  It  is  a  broad  sand  flat,  its  material  derived  partly  from 
the  sands  brought  down  from  the  Leverett  Lake  deposits  (see  p.  584)  and 
partly  from  cutting  into  the  kettle-holed  sands  carried  along  the  side  of 
the  Pelham  Hills  before  the  departure  of  the  ice  and  left  at  a  level  higher 
than  that  of  the  lake  (m  t,  PI.  XXXV,  C).  Fort  River,  opposite  Amherst, 
coming  out  of  the  Pelham  basin,  adds  somewhat  to  its  width,  but  less  than 
one  would  expect,  the  main  portion  of  the  sands  brought  down  by  this 
stream  having  been  at  an  earlier  period  carried  southward,  as  detailed  on 
page  578. 

South  of  this  stream  the  terrace  is  a  marked  bench  cut  in  the  sands 
thus  carried  along  the  slope  at  a  higher  level  than  its  own  (m  t),  and  it 
swings  round  the  west  side  of  the  great  drift  hill  north  of  Dwight's  station 
and  continues  east  as  a  horizontal  bench  notched  in  the  south  face  of  the 
delta  of  the  earlier  and  higher  stream  (see  p.  589).  It  was  thence  continued 
south  and  west  as  a  bench  cut  in  the  older  sands  across  the  entrance  of  the 
Belchertown  Pass,  for  at  this  time  the  waters  certainly  did  not  go  through  this 
pass,  as  the  lowest  point  in  the  sands  across  north  of  the  Belchertown  ponds 
is  about  30  feet  above  the  high  terrace  in  this  latitude.     It  is  continued 

MON  XXIX 41 


642  GEOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 

westward  along  the  north  foot  of  the  Holyoke  range,  still  as  a  bench  cut  in 
the  irregular  sands  which  are  heaped  so  high  along  its  flanks. 

SHORE   NOTCHES   IN   THE   SIDES   OP   DEUMLINS. 

Along  its  western  side  the  East  Street  basin  is  bounded  by  a  continuous 
line  of  di'umlins,  and  the  high  terrace  is  marked  by  a  horizontal  fluting  cut 
in  these  drift  hills.  As  all  the  hills  south  of  Amherst  village  stood  as 
islands  in  the  lake,  while  narrow  channels  connected  the  East  Street  basin 
with  the  rest  of  the  lake  to  the  west,  this  fluting  surrounds  them  on  all 
sides,  and  the  same  was  true  of  the  great  block  of  hills  north  of  the  village 
until,  by  the  extension  of  the  delta  of  Mill  River,  or  Cushmans  Brook,  it 
was  joined  to  the  mainland  and  made  a  peninsula. 

This  horizontal  fluting  is  well  shown  in  the  drumlin  which  rises  north 
of  the  Methodist  Church  in  Amherst.  Starting  from  the  top  of  the  hill, 
one  follows  down  on  either  side  its  regular  curved  slope  for  a  distance, 
when  it  suddenly  grows  much  steeper,  and  then,  at  the  300-foot  contour, 
begins  a  much  easier  slope.  One  comes  down  to  this  contour  line  on  till, 
but  here  begins  a  shore  gravel  bed,  at  first  thin,  but  thickening  outward,  as 
its  surface  has  a  lesser  slope  than  the  old  surface  of  the  drumlin  upon 
which  it  rests. 

So  long  as  this  East  Street  basin  was  open  to  the  north,  the  water 
moved  through  here  with  considerable  velocity  in  flood  time  and  swept 
such  material  as  it  could  erode  from  the  drift  hills  themselves  southward 
along  their  slopes  (there  were  no  brooks  in  these  isolated  hills  to  bring 
down  material  and  build  up  deltas),  and  so  the  bench  along  this  side  is 
scantily  represented  by  slojDing  sheets  of  gravel  concentrated  from  the  till. 

Just  north  of  the  New  London  Northern  Railroad  station,  for  several 
hundred  feet  west  of  and  above  the  railroad,  the  bench  widens  into  a  con- 
siderable sand  plain,  recently  built  over.  The  sands  dip  south  in  great 
sheets,  which  were  pushed  over  the  south  front  of  a  deltalike  bar  and  carried 
south  through  the  notch  in  which  the  railroad  runs. 

Across  the  village  of  Amherst  the  waters  of  the  two  basins  were  con- 
tinuous. Farther  south  the  fluting  is  carried  along  College  Hill  below  the 
church  and  the  gymnasium.  It  surrounds  the  long  isolated  drumlin  south- 
east of  College  Hill,  and  the  section  through  the  south  end  of  this  hill  made 
by  the  Central  Railroad  showed  that  a  great  hooked  bar  of  gravel  was 


SHORE  NOTCHES  IN  DRUMLINS,  643 

carried  oxit  south  from  the  nucleus  of  till  with  an  anticlinal  structure  like 
a  nest  of  inverted  canoes,  a  type  repeated  in  connection  with  all  the  other 
isolated  drumlins  farther  south. 

At  first  the  axis  of  the  bar  seems  to  have  been  shifted  now  to  the  right 
and  now  to  the  left,  only  part  of  the  deposit  of  each  position  being  retained 
2)ermanently.  Then  the  layers  are  continuous,  flat  on  the  top  for  30  to  50 
feet,  and  dip  east  and  west.  On  the  west  side  it  was  built  up  with  easier 
slope  and  finer  material,  as  the  bar  was  being  carried  south  across  the  some- 
what land-locked  bay  south  of  College  Hill,  where  it  opened  eastward 
into  the  East  Street  lake,  and  the  main  current,  sweeping  down  the  East 
Street  channel,  not  yet  closed  on  the  north,  wore  a  deep  fluting  into  the 
east  side  of  the  di-umlin  and  carried  the  material  south  in  great  sheets  of 
coarse  gravel,  often  3  to  8  feet  thick,  to  form  the  eastern  slopes  of  the  canoe- 
shaped  layers,  while,  if  we  follow  these  sheets  over  to  their  western  slopes, 
we  find  them  made  up  of  much  finer  sand,  at  times  slightly  gravelly.  At 
the  bottom  of  the  western  slopes  the  sheets  run  west  horizontally  for  a  little 
distance  and  then  mount  up  gradually  onto  fine  clays,  which  latter  in  turn 
sink  with  slight  dip  eastwardly  beneath  the  sands  and  below  the  level  of  the 
cutting.  This  shows  that  the  water  stood  at  this  high  level  for  a  long  time, 
allowing  the  fine  clays  to  accumulate  (which  happened  at  a  higher  level  in 
this  sheltered  bay  than  in  the  deep  East  Street  basin),  before  the  bar  was 
pushed  south  over  them. 

The  village  of  Soxith  Amherst  is  built  on  such  a  bar  carried  as  a  ridge 
from  one  drumlin  to  another,  and  the  road  running  south  from  the  village 
keeps  on  the  bench  around  the  east  side  of  the  great  di-umlin  south  of  the 
village,  and  follows  the  bar  that  projects  southwardly  from  it  to  join  the 
high  terrace  at  the  "Bay  road"  along  the  northern  flank  of  Holyoke. 

South  of  College  Hill  is  a  deep  depression,  just  mentioned,  sheltered 
on  all  sides  by  drift  hills,  and  never  filled  up,  and  another,  much  more 
extensive,  lies  west  of  the  village  of  South  Amherst. 

On  the  decline  of  the  waters  a  stream  draining  the  East  Street  lake 
found  its  way  between  drift  hills  into  the  first,  and  from  this  into  the  second, 
of  these  partially  isolated  bodies  of  water,  and  through  the  western  line  of 
drift  hills  into  the  main  basin,  and  cut  its  way  down  through  the  drift  so 
slowly  that  separate  terraces  were  formed  around  the  East  Street  lake, 
where  the  streams  entered  it  from  the  Pelham  Hills.     Ultimately  these 


644  GEOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 

streams,  uniting  in  the  bottom  of  the  drained  lake,  completed  the  erosion  of 
the  present  sinuous  course  of  Fort  River,  across  the  drift  area  south  of  the 
college,  apparently  to  a  level  somewhat  lower  than  the  present  bed  of 
the  river,  without  striking  rock,  for  the  stream  now  flows  over  a  muddy 
bottom,  and  there  is  no  trace  of  the  sheet  of  bowlders  which  it  must  have 
concentrated  out  of  the  till.  It  has,  however,  sufficient  slope  for  a  water 
power,  and  the  ponding  back  may  have  caused  it  to  cover  this  up,  as  below 
the  dam  it  flows  over  a  bottom  of  coarse  bowlders. 

THE   HIGH   TERRACE   OR  BENCH   ALONG  THE   WEST   SIDE   OF   AMHERST   RIDGE. 

So  long  as  the  water  passage  from  the  main  basin  into  the  north  end 
of  the  East  Street  basin  was  open,  and  the  sands  of  Cushmaus  Brook  (or 
Mill  River)  were  carried  down  along  the  flank  of  the  Pelham  Hills,  the 
work  of  the  lake  waters  along  the  west  side  of  the  Mount  Pleasant  block 
of  hills,  and  along  the  west  side  of  College  Hill,  and  its  prolongation  north- 
ward to  the  head  of  Prospect  street,  and  of  Mount  Doma  farther  south, 
consisted  mainly  in  the  concentration  of  a  coarse,  well-washed  and  well- 
rounded  beach  gravel  out  of  the  till,  of  which  all  these  hills  are  composed. 

Because  of  the  narrowing  of  the  channel  by  the  hills  named  above, 
and  by  Mount  Warner,  farther  west  in  mid-channel,  the  current- was  here 
somewhat  accelerated,  and,  aided  also  by  the  prevailing  west  winds,  wore 
with  exceptional  force  into  the  hillsides  along  the  line  we  are  now  trac- 
ing, cutting  deep  into  the  till  along  the  300-foot  contour,  or  a  little  lower, 
as  the  effective  erosion  level  was  often  somewhat  below  the  highest  water 
stand,  and  forming  thus  a  broad  horizontal  or  outwardly  sloping  bench  in 
the  till,  over  which  sheets  of  the  concentration  gravel  spread  in  bars  and 
low  ridges. 

The  exceptionally  steep  slope  above  the  300-foot  contour,  often,  indeed, 
slightly  concave,  which  I  have  called  the  horizontal  fluting,  is  best  devel- 
oped along  the  west  flank  of  Mount  Pleasant  and  its  continuation  north 
past  the  Plant  House  and  through  the  chestnut  woods  farther  north.  All 
the  plain  south  of  the  Plant  House  has  been  formed  thus  by  erosion,  and  the 
hill  formerly  extended  here  as  far  west  as  the  new  road  to  North  Amherst 
across  the  College  farm. 

The  gravel  spread  over  this  plain  in  great  sheets  has  been  largely  used 
for  sidewalks,  taken  mostly  from  the  pits  just  south  of  the  Plant  House. 


THE  HIGH  TERRACE  IN  AMHERST.  645 

where  a  few  feet  of  dig-ging  exposes  the  till  below.  This  2:)lain  sinks  away 
to  the  iK'xt  lower  level  on  the  west,  that  on  which  the  Agricultural  College 
Ijuildings  are  placed,  because  the  old  surface  of  the  till  had  this  configura- 
tion and  was  not  filled  uj),  the  outer  (western)  portion  of  this  latter  plain 
being,  however,  made  up  of  thick  sands  through  which  the  brook  has  cut 
between  the  college  buildings.  This  sand  is  the  southern  tongue  of  the 
delta  of  Cushmans  Brook,  carried  along  the  western  flank  of  the  Mount 
Pleasant  hill  after  this  delta  had  grown  across  so  as  to  abut  against  the 
north  end  of  this  hill,  and  had  thus  built  out  the  great  sand  plain  which 
stretches  north  therefrom,  and  the  main  current  of  the  brook,  rounding  the 
hill  itself,  carried  the  sand  south  along  its  western  flank,  at  a  level  much 
below  that  of  the  high-water  stand  of  the  lake. 

Farther  south,  Mount  Pleasant  breaks  down  suddenly,  and  a  short  dis- 
tance to  the  west  a  rocky  projection  at  the  head  of  North  Prospect  street 
rises  30  to  40  feet  above  the  old  high-water  stand.  This  mass  of  rock, 
which  has  now  been  mostly  covered  up,  used  to  be  called  Pikes  Peak,  and 
for  convenience  I  will  continue  to  employ  that  name.  Between  Mount 
Pleasant  and  Pikes  Peak  the  water  had  free  communication  with  the  East 
Street  basin  across  the  village  of  Amherst.  The  water  line  followed  the  300- 
foot  contour  around  the  south  spur  of  Mount  Pleasant,  extended  as  a  rounded 
bay  up  its  eastern  side,  skirted  on  the  south  the  hill  on  which  Professor  Tyler's 
house  stands,  and  so  swung  around  northeast  to  join  the  broader  terrace 
above  the  railroad.  (See  p.  642.)  From  Pikes  Peak  the  water  line  extended 
south  just  west  of  and  at  the  next  level  below  Prospect  street  for  the  whole 
length  of  this  street,  turned  southeast  through  the  grounds  of  the  president's 
house,  crossed  South  Pleasant  street  and  ran  at  the  foot  of  the  sharp  slope 
south  of  the  Octagon,  skirted  the  College  Hill  on  the  south  and  east,  and 
on  the  north  ran  just  north  of  the  Lucius  Boltwood  house,  now  Hitchcock 
Hall,  and  along  the  south  border  of  the  common,  and  bending  north  and 
crossing  Pleasant  street  it  ran  north  just  west  of  this  main  street  of  the 
village,  past  the  hotel  front,  to  the  point  o£  beginning  at  Pikes  Peak.  Thus 
an  L-shaped  island,  with  the  College  Hill  as  its  horizontal  and  the  Prospect 
street  ridge  as  its  vertical  portion,  rose  above  the  level  of  the  flood  waters, 
which  came  up  almost  exactly  to  the  level  of  the  post-office  steps.  It  must 
be  remembered  that  the  level  of  the  college  chapel  was  once  continuous 
under  the  Octagon,  the  library,  and  the  XW  house,  and  that  the  deep  notches 


646  GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

of  the  roadways  are  the  result  of  subsequent  excavation,  and  that  the  surface 
is  chang-ed  by  grading  north  of  Walker  Hall  and  the  Octagon. 

Through  this  passage  between  Mount  Pleasant  and  Pikes  Peak  there 
was  a  steady  set  of  the  current  which  has  built  up  the  broad  area  of  finely 
washed  and  sorted  gravels  Avhich  stretch  across  and  down  through  the  pass 
and  which  are  well  exposed  all  round  the  Catholic  Church.  Southeastward 
they  stretch  as  a  flat  of  finer  sands,  with  a  layer  of  concentration  gravel 
capping  it,  across  from  Professor  Tyler's  hill  to  College  Hill.  The  two  stone 
churches  and  the  high-school  building  are  on  this  sand  plain.  College 
street  lies  so  near  its  border  that  the  houses  on  the  north  side  have  cellars 
in  sand;  those  on  the  south  side  have  wet  cellars,  as  they  cut  through  the 
thin  border  of  the  sand  and  get  the  drainage  which  conies  down  from  the 
College  Hill  on  the  sm-face  of  the  impervious  till  beneath. 

The  current  swept  the  sands  across  in  a  line  from  the  Catholic  Church 
to  the  high-school  building  and  the  common.     An  area  in  the  recess  of  the 

N 

^UegeJIiiL.  s 

~^  Cen/rdlRR.. 


TOZ. 

Fig.  37 Section  of  shore  beds  of  Hadley  Lake  soutli  of  College  Hill,  at  Amherst.    The  cutting  was  18  feet  deep. 

L-shaped  island,  the  south  half  of  the  common,  was  not  filled  up  quite  to 
the  true  level  and  was  miderlain  by  till  at  no  great  depth,  and  so  was  orig- 
inally a  very  swampy  place.  It  has  been  filled  in  considerably,  and  along 
most  of  the  street  to  the  east  and  the  whole  of  the  street  to  the  west  of  it 
the  artificial  filling  has  been  so  great  that  the  waterworks  ditches  did  not 
reach  the  undisturbed  sands. 

Along  the  whole  west  side  of  the  L-shaped  island  the  level  of  Lincoln 
street  is  the  level  of  the  high  terrace.  It  is  a  bench  cut  in  the  till,  very 
broad,  and  but  little  covered  by  sands,  since  all  that  the  main  stream 
obtained  from  the  delta  of  Cushmans  Brook  was  swept  in  across  the  village 
to  the  East  Street  basin. 

Thin  cappings  and  bars  of  sand  are  applied  to  its  surface  and  to  the  slope 
down  to  the  lake  bottom,  and  can  be  well  studied  from  the  side  of  Mount 
Warner.  Along  Lincoln  street  the  cuttings  of  the  waterworks  struck  till 
for  more  than  half  the  distance,  and  along  every  street  which  crosses  this 


TEIE  HIGH  TERRACE  IN  AMHERST. 


647 


shore  lino  I  have  at  one  time  or  anc.ther  had  opportunity,  hi  cuttings  of  the 
water  t>r  <>iis  companies,  to  locate  exactly  this  old  shore  line  and  plain. 

CoUeo-e  Hill  breaks  down  like  Mount  Pleasant,  and  southwest,  at  Professor 
Harris's  house,  begins  another  drunilin,  named  Mount  Doma  (by  President 
Hitchcock),  from  its  regular  shape.  Between  the  two  the  waters  passed 
southeast  into  the  depression  south  of  College  Hill,  and  a  broad,  thin  sheet 
of  gravel  stretches  through  the  pass,  and  is  well  exposed  in  the  cutting  of 
the  Centi-al  Railroad.  Everywhere  through  this  pass  the  till  is  but  a  little 
distance— at  most  6  feet— below  the  surface,  as  at  the  bridge  over  this 
cutting  on  Woodside  avenue. 


Fig.  38— Enlarged  section  of  the  sonth  side  of  cutting  shown  in  flg.  37.    The  section  represents  the  aouth  side  of  the 

railroad  out  beneath  the  bridge  shown  in  flg.  37. 

Fig.  37  shows  a  section  south  from  the  Octagon,  on  College  Hill,  through 
the  ciitting  of  the  Central  Railroad,  at  the  point  where  the  highway  crosses 
it.  It  is  interesting  as  showing  sands  under  the  clays  and  separating  them 
from  the  till.  This  is  the  only  instance  of  the  kind  I  have  seen  in  the 
valley.  The  clays  thicken  off  into  the  deep  water  south  and  southeast,  and 
northward  grade  to  sand  layers,  and  these  to  the  beach  gravels  which  make 
this  broad  flat  and  which  are  spread  over  the  bench  cut  back  in  the  till,  by 
which  cutting  the  sharp  slope  south  of  the  Octagon  was  produced.  The 
varying  currents  from  the  west  are  finely  shown  by  the  detailed  sections 
figs.  38,  39.  The  quiet  water  allowed  the  clay  layers  to  form,  and  then  the 
strong  current  crumpled  them. 


648  GEOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 

Farther  south,  the  terrace  swinging  round  either  side  of  Mount  Doma 
is  continued  in  an  exceptionally  long  spit  of  gravel  which  bends  round 
southwest  and  continues  to  Fort  River,  and  beyond  the  river  a  peculiar 
ridge  of  sand,  sloping  down  gradually  to  the  depression  west  of  South 
Amherst  and  westerly  to  the  main  basin,  is  carried  south  to  the  high  ter- 
race skirting  the  north  flank  of  Mount  Holyoke.  This  seems  to  me  a  bar 
thrown  across  the  mouth  of  the  deep  bay  which  occupied  the  second  depres- 
sion, mentioned  above  (p.  643),  by  the  current  of  the  main  stream  coming 
down  through  the  channel  between  Mount  Warner  and  the  Amherst  ridge. 

THE  BENCH  AROUND  MOUNT  WARNER. 

As  one  looks  at  this  isolated  rocky  hill  from  Amherst  a  northern  por- 
tion, horizontal  and  at  the  level  of  the  high  terrace,  attracts  attention,  and 
investigation  shows  this  to  be  a  broad,  rudely  horizontal  rocky  bench  but 
slightly  covered  with  loose  material.     To  assume  that  this  perfectly  terrace- 


-I  SOMm. 


Fig.  39. — Detail  of  clay  layer  cnimpled  \f^  the  current,  from  fig.  38,  to  show  how  the  layer  was  carried  along  hy  the 

friction  of  a  current  from  the  west. 

like  portion  of  the  mountain  was  planed  down  to  the  level  of  the  high  ter- 
race by  the  flood  waters  would  be  to  assume  that  this  flood  period  was 
immensely  longer  than  we  have  been  accustomed  to  think  it,  and  longer 
than  the  other  phenomena  connected  with  it  would  seem  to  warrant. 

An  inspection  of  the  map  will  show  that  south  of  the  mountain  a  great 
tail  of  sand  extends  southeast  to  the  Northampton  road.  Just  under  the 
south  end  of  the  mountain  a  pond  occupies  the  place  where  the  waters  meet- 
ing from  both  sides  around  the  mountain  stagnated  and  thus  prevented  the 
sands  from  building  up  quite  to  the  highest  level,  but  farther  south  a  broad, 
perfectly  level  sand  plain  projects  at  the  level  of  the  high  terrace  southeast- 
ward, indicating  the  direction  of  the  current.  (See  map,  PL  XXXV,  C.)  I 
imagine  it  to  have  been  deflected  somewhat  by  the  prevailing  west  wind. 
This  tail  sinks  like  a  delta  southward  and  runs  out  on  the  clay  bottom  of 
the  lake,  reaching  nearly  the  Northampton  road.  On  the  west  side  it  flanks 
the  mountain  for  a  long  way  north,  but  is  so  blended  with  dunes  carried 
up  from  below  that  its  original  relations  can  not  be  clearly  made  out. 


THE  LAKE  BENCH  NORTH  OF  HOLYOKE  llANGE.  649 

This  bntad,  Hut,  siuid- covered  jjlateiui  in  continuation  of  the  soutli  end 
of  ^Idiint  Warner  has  the  exact  heiglit  of  the  old  Hadley  Lake.  Its  direction 
(southeast)  was  a  great  puzzle  to  me,  and  I  tried  to  explain  it  by  supposing- 
that  the  south  current  and  the  west  wind  produced  a  resultant  southeast 
direction  in  the  great  sand  spit.  Recently  (1888)  excavations  along  the 
road  south  from  the  Catholic  cemetery  have  shown  that  all  along  the  south- 
east front  of  the  plateau  the  till  lies  almost  at  the  surface  and  makes  the 
explanation  more  probable  that  the  whole  mass  of  the  deposit  is  due  to 
ice,  and  that  the  north-south  valley  movement  of  the  ice  is  here,  where 
the  valley  is  xinusuall}^  wide  and  open,  replaced  by  the  usual  upland 
(N.  30°  E.)  movement,  and  this  agrees  with  the  strong  pressure  of  the  ice 
along  the  west  face  of  Deerfield  Mountain.  Only  the  surface  and  slopes  of 
the  plateau  were  then  molded  later  by  the  water  and  covered  and  flanked 
by  sand  bars. 

THE  LAKE  BENCH  ALONG  THE  NORTH  SLOPE  OF  THE  MOUNT  HOLYOKE  AND 

MOUNT  TOM  RANGE. 

I  have  already  (p.  586)  called  attention  to  the  fact  that  great  masses  of 
irregular  sands  are  in  places  heaped  up  against  the  flanks  of  these  ranges  at 
heights  much  above  the  highest  water  level  of  the  Hadley  Lake.  Where, 
as  along  south  of  Amherst,  the  high  terrace  is  a  bench  cut  in  these  sands  it 
sinks  gradually,  and  often  without  any  marked  change  of  slope,  into  the 
lake  bottom,  as  if  there  had  been  here  no  marked  current,  but  an  undertow 
had  drawn  the  sands  in  large  quantity  down  into  the  deeper  water. 

Farther  west,  south  of  Hadley  and  in  the  Holyoke  notch,  the  current 
was  more  marked;  but  the  material  at  the  disposal  of  the  stream  was  less 
in  amount  and  the  terrace  is  a  narrow  bench,  often  of  till,  and  from  the 
entrance  of  the  notch  down  to  Titans  Pier  the  waters  cut  back  the  till  in  a 
broad  bench  and  then  wore  into  the  trap  and  sandstone,  producing  a  ver- 
tical wall  which  the  talus  of  fallen  trap  has  not  yet  obliterated. 

Across  the  river  the  same  conditions  hold.  Above  the  highest  terrace 
level,  as  determined  by  its  coincidence  with  the  Florence  plain,  higher 
levels  of  coarse  sand  occur  and  the  lake  bench  slopes  inward  to  where  it  is 
cut  off  by  the  later  erosion  of  the  Connecticut,  or  when  we  get  beyond  this, 
as  in  Easthampton,  it  continues  its  gradual  slope  to  the  middle  of  the  basin, 
or  to  the  line  of  the  deeoest  water  of  the  broad  stream  which  flowed  down 


650       GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

across  the  Hampton  plain.  Along  this  portion  of  its  course,  between  Nona- 
ttick  and  Mount  Tom,  fine  bowlder  beaches  mark  the  outer  boundary  of  the 
high  terrace. 


THE   WESTFIELD   PLAIN. 


I  have  followed  tlie  high  terraces  on  either  side  of  the  broad  Hadley 
Lake  and  found  them  much  more  intimately  connected  with  the  Southamp- 
ton Valley  than  through  the  gorge  of  Mount  Holyoke  with  the  Springfield 
basin.  They  are  confluent  with  the  broad  Westfield  plain,  one  of  the  most 
interesting  deposits  of  the  river. 

The  broad,  unfilled  lake,  15  miles  wide  opposite  Northampton,  nar- 
rowed across  Southampton  to  a  width  of  3  miles,  and  on  the  south  line  of  this 
town  two  long  ridges.  White  Loaf  and  the  high  hill  to  the  west  of  it.  East 
Farms  Hill,  rose  as  islands  in  its  course,  and  the  waters  passed  on  south  by 
three  narrow  channels — respectively  180  rods,  120  rods,  and  360  rods  wide, 
counting  from  west  to  east — into  the  "Westfield  plain,  the  filled-up  portion 
of  its  ancient  bed.  These  passes  formed  a  waste  gate  through  which  the 
overflow  of  the  river  went  with  velocity  accelerated  by  the  narrowing  of 
its  passageway.  It  swept  the  abundant  kame  sands  (m  t)  which  had  been 
spread  at  the  western  foot  of  the  Mount  Tom  range  and  over  White  Loaf 
through  the  eastern  and  middle  channels,  and  this  is  the  proximate  source 
of  the  trap  pebbles  traced  far  south  across  the  plain  by  Mr.  Diller.-'  The 
sands  of  the  Manhan  were  spread  by  it  over  the  western  portion  of  the  plain- 
As  a  result,  we  haA^e  coarse  gravels  concentrated  from  the  kame  gravels  in 
the  eastern  gorge,  stretching  far  south  across  Hampden  plain  and  growing 
gradually  finer,  and  in  the  same  latitudes  on  the  western  side  of  the  plain 
the  sands  are  much  finer,  being  derived  from  the  sands  of  the  Manhan. 

That  the  sand  here  had  this  origin  in  local  kame  deposits  is  manifest 
from  the  fact  that  along  the  whole  course  of  the  Holyoke-Tom  divide  there 
are  no  streams  flowing  into  the  river  to  bring  sediment,  and  through  all  this 
length  the  high  terrace  is  for  long  distances  wanting  or  marked  only  by  a 
narrow  shelf  cut  into  older  deposits,  and  certainly  nothing  was  brought 
from  the  upper  waters  of  the  river  across  the  broad,  low  clay  bottom  of 
the  lake  in  Easthampton. 

The  delta  deposits  of  the  Loudville  branch,  swept  along  the  west  side 
of  the  basin,  had,  south  of  Southampton  village,  shrunk  to  a  naiTOw  shelf, 

ij.  S.  Diller,  Geol.  of  Westfield:  Westfield  Times  and  News  Letter,  Sept.  19,  1877. 


THE  WESTFIELD  PLAIN.  651 

and  \vt,  iiniuediately  after  passing  the  two  obstructing  hills,  the  waters 
liaA'e  filled  the  broad  valley  (which  is  over  B^  miles  across  at  its  narrowest 
point)  well-nigh  to  the  height  of  the  highest  terrace,  everywhere  from  side 
to  side,  and  for  10  miles  south.  Where  the  waters  swept  around  the  two 
hills  mentioned  above,  broad  grooves  appear  in  the  plain,  hugging  the  sides 
of  each  hill  (If),  and  joining  and  running  out  southward  on  the  plain  for  a 
long  distance,  with  a  tail  of  higher  sands  between  them;  and  from  the  south- 
east corner  of  White  Loaf  a  heavy  bar  of  coarse  gravel  (1  s  h)  runs  out 
southeast,  and  east  of  this  was  left  the  great  depression  of  the  Hampden 
ponds. 

White  Loaf  ends  near  the  north  line  of  Westfield,  but  the  East  Farms 
Hill  is  continued  in  a  low,  broad  reach  of  till  down  halfway  to  Westfield 
village,  dividing  the  plain,  but  in  all  its  southern  portion  hardly  rising 
above  the  surface  of  the  highest  waters,  and  bounded  by  a  marked  bowlder 
beach. 

On  the  west  side  was  the  real  thread  of  the  current  of  the  broad  river, 
and  this  was  early  utilized  for  the  Farmington  Canal.  Just  on  the  north 
line  of  Westfield  the  main  stream  received  the  waters  of  the  Manhan,  and 
the  increased  eroding  power  derived  from  their  junction  is  seen  in  the  lower- 
ing of  the  plain  for  a  mile  south  of  the  town  line.  This  was  aided,  also,  by 
the  narrowing  of  the  channel  through  this  distance.  Then  the  valley  quite 
suddenly  doubles  in  width  and  the  low  thread  continues  along  its  eastern 
side,  hugging  the  East  Farms  Hill,  and  the  plain  is  gradually  built  up  to  a 
much  greater  height  along  its  western  half,  and  for  a  long  distance  south 
the  height  of  its  western  edge  is  300  feet,  and  it  slopes  east  very  gradually 
40  feet  and  then  quite  rapidly  25  feet  more  to  the  bottom  of  the  deep-water 
channel.  Southward,  the  highest  point  in  this  channel  is  a  mile  south  of 
East  Farms,  where  the  south  end  of  the  East  Farms  Hill  drops  down  and 
the  two  valleys  come  together.  North  of  this  all  the  brooks  which  come 
from  the  hills  of  West  Farms  and  East  Farms  gather  in  this  deep-water  cur- 
rent bed  and  run  north. 

The  terracelike  slope  which  borders  this  deep-water  channel  on  the  west 
bends  round  (north  of  F.  W.  Griswold's)  to  the  west  and  runs  west  to  the 
slope  of  Pochassic  Mountain.  The  corresponding  slope  which  bounds  the 
channel  on  the  east  bends  east  at  the  same  point,  and  the  westward-running 
last-mentioned  slope,  if  prolonged  eastward,  would  just  meet  and  be  continued 


652  GEOLOGY  OF  OLD  HAMPSHIKE  COUNTY,  MASS. 

by  tliis  similar  slope,  which  stretches  east  from  the  Catholic  cemetery  across 
the  Hampden  plain. 

The  highest  sands  (1  s  h)  on  the  east  and  west  sides  of  the  plain  run 
south  with  regular  slope  and  then  drop  quite  abruptly  in  this  terracehke 
construction  scarp.     The  deep  cuttings  of  the  Westfield  and  Holyoke  Rail- 
road and  the  many  openings  on  the  north  edge  of  the  Westfield  basin  do 
not  give  any  sign  that  the  Westfield  ever  wore  up  to  the  foot  of  this  scarp. 
Everything  indicates  rather  that  the  whole  plain  north  and  south  of  the 
later-eroded  basin  of  the  Westfield  was  the  result  of  one  continuous  opera- 
tion, and  that  this  scarp  was  formed  east  and  west  across  the  channel  of  the 
main  stream  just  where  the  waters  of  the  Westfield  River  joined  its  waters, 
and  the  outlet  through  the  Divide  Range  gave  a  means  of  communication  with 
the  eastern  lake,  and  thus  the  carrying  power  of  the  main  stream  was  sud- 
denly lessened  along  this  hne,  and  the  scarp  was  the  index  of  that  lessening. 
The  diminished  current  carried  finer  material,  and  in  the  steep  erosion  scarp 
by  which  one  descends  from  the  south  edge  of  the  plain  to  the  Westfield 
River  basin,  a  mile  south  of  the  Catholic  cemetery,  we  have  many  deep 
sections  showing  a  great  thickness  of  sands  so  fine  that  the  owners  have 
often  attempted  to  utihze  them  for  brick  making,  but  without  success.     On 
the  south  of  this  broad  original  depression  which  guided  the  Westfield 
rivers  finally  back  to  the  gorge  in  the  Divide  Range  and  to  the  Connecticut, 
the  fine  sands  continue  in  "Poverty  plain,"  west  of  Little  River,  rising  from 
229  feet  on  the  edge  north  of  the  Westfield  basin  to  264  feet  on  the  south 
of  the  basin  of  the  Little  River,  in  the  center  of  Poverty  plain — an  enormous 
waste  of  desolate  sands  whose  increased  height  comes  from  the  sands  of  the 
Westfield  rivers  swept  down  around  the  high  drift  hills  of  the  "Fox  district." 
The  broad  "Avenue  plain"  between  the  two  Westfield  rivers  is  a  very 
interesting  portion  of  the  original  plain  of  the  flooded  river.     It  is  now  about 
a  mile  wide  and  4  miles  long,  and  stretches  from  where  it  rests  against  the 
drift  border  of  the  valley  between  the  two  Westfield  rivers,  at  a  height 
of  290   feet,  eastward  to  the  cemetery  in  Westfield,  descending  16   feet 
per  mile  (Diller),  and  bounded  north,  south,  and  east  by  the  deep  erosion 
basins  of  the  two  rivers.     It  is  made  u.p  very  largely  of  quite  coarse  and 
well-washed  gravels,  even  out  at  its  eastern  end,  which  are  exposed  in 
many  natural  sections  and  gravel  pits,  notably  just  east  of  the  cemetery, 
where  the  well-sorted  and  rounded  gravel  is  12  to  14  feet  thick  and  rests 


THE  WKSTFIIOLl)  PLAIN.  653 

Upon  sands.  These  sheets  of  gravel  stretched,  1  have  no  doubt,  right  across 
the  area  now  occupied  by  the  basin  of  the  Westfield  River,  and  were  con- 
tinuous with  the  fine  gravels  just  northwest  of  and  above  the  railroad  station. 
Here  tliore  is  a  tlK)roughly  classified  bed  of  4  to  6  inch  pebbles,  all  well 
rounded  and  made  up  very  largely  of  the  peculiar  hard  Laurentian  gneiss 
of  Washington  and  Hinsdale  and  of  the  Berkshire  quartzites,  both  brought 
down  from  the  lieadwaters  of  the  Westfield  River. 

Mr.  Diller  calls  attention  to  the  depression  of  the  east  end  of  this  Ave- 
nue plain  1 7  feet  below  the  adjacent  plains.  I  believe  this  plain  to  have  been 
formed  as  it  now  is  during  the  flood  time  of  the  main  river,  and  to  owe  its 
slope  to  the  heavy  flood  of  the  Westfield  River,  which  kept  this  passage 
between  Pochassic  Mountain  and  the  West  Parish  Hills  Scoured  out,  and 
cari-ied  out  over  its  bottom  the  broad  sheets  of  coarse  gravel  which  reach 
east  to  the  village  of  Westfield.  The  position  of  these  gravels  over  the 
underlying  sands  is  the  normal  one  all  up  and  down  the  valley  wherever 
a  delta  is  advanced  into  deeper  water,  and  the  two  beds  are  parts  of  the 
result  of  a  single  operation.  The  flood  of  the  Westfield  then,  as  now,  pre- 
ceded that  of  the  main  stream,  and  thus  annually  swept  its  channel  clear 
and  gradually  built  up  its  heavy  gravel  beds. 

Poverty  plain  is  continuous  across  Westfield  and  into  Southwick. 
It  begins  to  contract  in  width  on  the  town  fine,  and  from  Southwick  Hill 
southward  has  a  width  of  little  more  than  a  mile  and  a  half.  The  con- 
finement of  the  waters  in  these  narrow  limits,  by  increasing  their  eroding 
power,  seems  responsible  for  the  long,  shallow  depression  of  the  Congamuck 
or  Southwick  Pond,  and  for  the  curious  course  of  Great  Brook,  which, 
starting  from  the  middle  of  the  pond  on  its  west  side,  runs  north  among  the 
drift  hills,  and,  leaving  them,  takes  a  diagonal  course  across  Poverty  plain, 
passing  within  100  rods  of  the  head  of  the  pond,  and  finding  what  I  imagine 
was  the  thread  of  the  current  of  the  main  stream  and  following  it  back 
until  it  joined  the  Westfield  near  the  divide  gorge. 

The  thread  of  the  current  passed  out  of  the  deep  water  over  South- 
ampton village  and  by  the  west  pass  down  to  and  across  the  place  where 
Westfield  village  now  stands,  and  then,  on  receiving  the  waters  of  the 
Westfield  rivers,  bent  east  to  near  the  gorge,  whence  it  followed  the  present 
course  of  Great  Brook  to  and  across  the  whole  length  of  Southwick  Pond, 
and  so  southward  across  the  Farmington  basin  and  by  the  course  of  Mill 
River  into  the  sound  at  New  Haven. 


654       GEOLOGY  OF  OLD  HAMPSHIEB  COUNTY,  MASS. 

An  inspection  of  tins  Westfield-Sotithwick  plain  as  represented  on  the 
map  will,  I  think,  convince  one  that  it  was  constructed  by  a  broad,  very 
shallov/  body  of  water,  often  broken  into  separate  threads  meandering'  across 
the  plain,  which  were  separated  from  one  another  by  long  intervening  bars 
and  spits,  bounded  by  construction  scarps,  at  times  quite  steep  and  fluted 
on  the  convex  side  of  the  curving  channels,  but  often  of  long  and  easy  slope. 

THE   GREATER    ELEVATION   OP   THE    TBERACBS    IN    THE   WBSTFIELD   THAN   IN    THE 
SPRINGFIELD   LAKE.      POSSIBLE   WESTERN  ELEVATION. 

Professor  Dana  has  noted  that  the  highest  nol-mal  terraces  in  the  west- 
ern valley  are  60  feet  higher  than  in  the  eastern.  Mr.  J.  S  Diller  has 
discussed  the  matter  in  an  interesting  article  which  was  published  in  the 
Westfield  Times  and  News  Letter,  September  19, 1877,  and  which  is  here 
reproduced : 

THE  GEOLOGY  OF  WESTFIELD  AND  VICINITY. 

By  J.  S.  Diller. 

Professor  Dana  has  shown  that  at  Tariffville,  Connecticut,  where  the  Farming- 
ton  Eiver  flows  through  the  Divide  range,  the  terraces  upon  the  west  side  of  the 
range  are  about  50  feet  higher  than  those  upon  the  east  side.  At  the  Westfield 
gap,  through  the  Divide  range,  the  upper  terrace  on  the  west  side  of  the  range  is  264J 
feet  above  sea  level,  but  on  the  east  side  the  highest  terrace  is  50  feet  lower.  It  has 
been  shown  by  Professor  Dana  that  during  the  Champlain  period  the  highest  flood 
level  over  Springfield  was  240  feet  above  the  sea  level.  We  have  shown  in  a  pre- 
vious article  that  during  the  same  period  the  highest  flood  level  on  the  west  side  of 
the  Divide  range  was  280  feet  above  sea  level.  The  flood  at  Westfield  was  at  least 
48  feet  higher  than  that  at  Springfield. 

The  question  at  once  arises.  Why  was  the  water  so  much  higher  on  the  west 
side  of  the  range?  The  answer  most  frequently  given  is  that  the  gaps  through  the 
Divide  range  were  closed,  thus  damming  the  water  back  and  raising  it  to  a  greater 
height  west  of  the  range.  In  the  Westfield  Eiver  gap,  upon  the  south  side  of  the 
river,  there  are  two  terraces.  The  lower  one  extends  directly  through  the  gap,  at  a 
height  of  199  feet  above  the  sea.  This  terrace  is  made  up  of  stratified  deposits,  con- 
taining a  large  portion  of  clay.  The  beds  extend,  with  the  terrace,  directly  through 
the  gap.  The  continuity  of  the  beds  is  evidence  that  the  gap  was  open  when  the 
deposits  were  made.  These  lower  deposits,  we  have  reason  to  believe,  were  made 
during  the  early  part  of  the  Champlain  period.  It  therefore  appears  that  during  the 
early  part  of  the  Champlain  period  the  gap  was  not  completely  closed  by  either  drift 
or  trap  rock.  It  should  here  be  remarked  that  there  is,  on  the  right  bank  of  the 
river,  just  east  of  Morley's  bridge,  in  the  gap,  a  ledge  of  trap  whose  top  is  21  feet 


THE  GKOLOOY  OF  WESTFIELD.  655 

above  tbe  highest  modern  flood  level  at  that  place.  The  ledge  breaks  the  coutimiity 
of  the  lowest  beds  of  the  terrace,  and  may  have  once  formed  a  considerable  dam  in 
the  gap.  Above  the  ledge  the  beds  are  continuons  through  the  gap,  and  are  evidence 
that  there  the  gap  was  oi)en. 

If  the  gaps  in  the  Divide  range  were  not  closed  during  the  Ghamplain  period, 
the  height  of  the  water  must  have  been  due  to  some  other  conditions.  There  were 
two  conditions  on  which  the  height  of  the  water  seems  to  have  depended,  viz:  (1)  The 
narrowness  of  the  gaps  through  the  Divide  range,  and  (2)  the  difference  in  slope  of 
the  valleys  east  and  west  of  the  range. 

Dr.  Davis,  in  his  History  of  Westfleld,  says  that  the  Westfield  Eiver  at  Westfleld, 
during  floods  in  1819  and  1826,  rose  U  feet.  Mr.  L.  F.  Eoot,  civil  engineer  of  this 
place  and  of  the  Canal  Railroad,  has  recorded  a  rise  of  12  feet  during  the  great  flood 
of  1SG9.  Mr.  Austin  Williams  made  marks  upon  a  tree  near  the  north  end  of  Morley's 
bridge,  showing  the  height  of  the  water  there  during  an  ice  flood  in  1855,  and  also 
during  the  flood  of  1869.  In  1855  the  water  rose  27  J  feet,  and  in  1869  it  rose  26  feet. 
It  thus  appears  that  when  the  river  rose  12  feet  at  the  village  it  rose  26  feet  in  the 
gap.  Some  of  the  excess  in  height  was  due  to  the  inflowing  water  from  Little  Eiver, 
but  by  far  the  greater  part  is  dne  to  the  smallness  of  the  gap  through  the  range. 

By  measuring  the  gap  it  has  been  determined  that  a  flood  nineteen  and  one-half 
times  as  great  as  the  highest  modern  flood  would  flow  through  the  gap  at  such  height 
as  to  cover  the  top  of  the  highest  terrace. 

The  overflow  from  the  Connecticut  and  Manhan  rivers  entered  the  Westfield 
Valley  by  two  large  streams,  neither  of  which  were  less  than  three-fourths  of  a  mile 
in  width,  and  one  having  a  depth  of  40  feet  in  its  most  shallow  portion.  Add  to  the 
water  poured  into  the  Westfield  Valley  by  these  two  streams  the  immense  floods  of 
the  Westfield  rivers  and  it  will  be  seen  that  for  such  floods  the  gap  through  the  Divide 
range  was  a  small  outlet.  The  smallness  of  the  gap  evidently  had  much  to  do  with 
Increasing  the  height  of  the  water  west  of  the  Divide  range. 

Supposing  the  stratified  drift  were  removed  from  the  valleys  on  both  sides  of  the 
Divide  range,  we  would  see  that  the  northern  portion  of  the  valley  on  the  west  side 
has  much  less  slope  than  the  corresponding  portion  of  the  Connecticut  Valley  on  the 
opposite  side  of  the  ridge.  The  valley  west  of  the  range  is  crossed  by  the  red  sand- 
stone divides  which  separate  the  Westfield  Eiver  Valley  from  the  Manhan  Eiver  Valley 
on  the  north  and  the  Farmington  Valley  on  the  south.  Such  divides  are  not  found  in 
the  Connecticut  Valley  on  the  opposite  side  of  the  ridge. 

The  lowest  parts  of  the  valley  west  of  the  Divide  range  are  those  across  whicli 
the  Westfield  and  Farmington  rivers  flow.  These  lowest  portions  are  considerably 
higher  than  the  lowest  parts  of  the  Connecticut  Valley  directly  opposite,  else  the 
Westfield  and  Farmington  rivers  would  not  flow  into  the  Connecticut. 

It  is  evident  that  at  the  close  of  the  Glacial  period  the  average  slope  of  the  valley 
west  of  the  Divide  range  was  much  less  than  that  of  the  opposite  portion  of  the  Con- 
necticut Valley.  The  two  valleys  filled,  during  the  Ghamplain  period,  with  water  from 
the  Connecticut  Valley,  in  the  region  of  Northampton,  acted  much  like  two  parallel 


656       GEOLOGY  OF  OLD  HAMPSHIEB  COUNTY,  MASS. 

troughs  having  their  source  in  the  same  place  and  at  the  same  level,  but  having  dif- 
ferent slopes.  The  water  in  the  one  having  the  least  slope  must  be  above  the  level  of 
the  water  in  the  other  at  all  points  directly  opposite. 

The  difference  in  slope  of  the  two  valleys,  together  with  the  narrowness  of  the 
gap  in  the  Divide  range,  seem  to  be  the  cause  of  the  greater  height  of  the  water  in 
this  vicinity. 

It  seems  that  the  following  considerations  should  be  weighed  in  seeking 
for  an  explanation  of  this  curious  difference  of  level: 

(1)  The  Springfield  basin  is  about  four  times  as  wide  as  the  Westfield, 
and  thus  much  more  material  would  be  required  to  fill  it  up  to  the  same  level. 

(2)  Because  of  the  northwestern  recession  of  the  ice  the  eastern  floods 
sent  the  mass  of  their  sands  down  through  the  Mouson-Wilhmantic  Valley 
or  lodged  them  in  the  great  series  of  catchment  basins  I  have  described 
above  as  the  eastern  series  of  glacial  lakes. 

(3)  The  same  recession  of  the  ice,  continued  northwestwardl}^,  caused 
the  heaviest  floods  to  pour  into  the  lateral  or  Westfield  Valley  by  all  the 
transverse  valleys  coming  in  from  the  west,  and  of  these  the  Westfield  River 
was  the.  most  important,  because  it  runs  back  northwest  across  the  whole 
plateau  of  the  Berkshire  Hills  and  at  Dalton  opens  broadly  into  the  great 
Housatonic  Valley,  and  because  it  remained  the  main  trunk  of  the  ice 
drainage  until  the  ice  had  receded  from  those  hills;  and  while  the  ice  front 
was  in  the  region  of  Pittsfield  the  di-ainage  of  a  portion  of  the  Upper  Housa- 
tonic was  deflected  into  this  valley,  producing  the  interesting  sand  plains  in 
the  upper  valley  at  Hinsdale  and  bringing  down  bowlders  from  this  region 
to  spread  over  the  Westfield  plain. 

The  combined  effect  of  these  three  conditions  seems  sufficient  to  explain 
the  lower  level  of  the  eastern  plain,  and  instead  of  saying  that  "the  flood  at 
Westfield  was  at  least  48  feet  higher  than  that  at  Springfield,"  I  should  say 
that  the  waters  were  48  feet  shallower  in  the  Westfield  basin  than  over 
Springfield. 

Where  kame  sands  were  heaped  up  in  the  Springfield  basin  the  high 
terrace  is  notched  in  them  at  nearly  the  same  height  as  in  the  Westfield 
basin;  as,  for  example,  on  the  extreme  east  of  the  basin  in  Wilbraham  or 
north  in  Holyoke.  At  the  notch  in  the  Divide  Range  occupied  by  the  West- 
field  River  the  exact  surface  of  the  lake  bottom  has,  of  course,  been 
removed  by  the  later  erosion  of  the  river;  but  at  the  next  notch  south,  at 
Risings,  just  on  the  State  line,  the  surface  is  well  preserved  and  is  very 
instructive.     It  is  what  might  be  expected  on  the  assumption  of  a  narrow 


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TUB  SPRINGFIELD  LAKE.  657 

i-liaiiiicl  between  the  two  extensive  bodies  of  water  and  a  larger  influx  into 
the  westiTii  basin,  and  thus  a  current  through  into  the  eastern.  There  was 
an  eroding  current  wliich  cut  a  narrow  channel  back  westward  from  the 
gap  and  transported  little  material  into  the  eastern  basin,  as  the  sands  of 
the  western  basin  were  delivered  into  it  on  the  other  (western)  side. 

In  the  Springfield  basin  the  broad  Agawam  plain,  220  to  230  feet  high, 
is  composed  of  fine  sand  and  extends  right  up  into  this  narrow  gorge,  which 
passes  tlu-ough  the  gap  and  bends  north  and  ends  abruptly.  This  channel 
is  not  occupied  by  a  brook,  and  after  passing  through  the  gap  in  the  trap 
range  it  extends  into  the  Westfield  plain,  being  there  worn  in  till  and  high 
terrace  gravels.  i 

Mounting  to  its  rim,  we  find  the  coarse  gravels  of  the  Westfield  plain 
at  280  feet  stretching  westward,  sinking  slightly,  and  growing  finer,  and 
forming  the  broad  sand  plain  that  extends  across  to  Congamuck  ponds.  A 
brook  which  flows  north  to  the  Westfield  River  has  cut  its  way  back  nearly 
to  this  dry  gorge;  but  the  latter  remains  still  intact,  though  a  high,  narrow 
ridge  is  all  that  now  separates  them.  This  dry  gorge  was  the  erosion  chan- 
nel caused  by  the  escape  of  part  of  the  surplus  waters  from  the  western  into 
the  eastern  basin.  The  waters  stood  at  practically  the  same  level,  but  the 
coarse  sands  that  drifted  south  in  the  western  basin  stood  at  280  feet,  and 
the  fine  sands  drifting  south  in  the  eastern  basin  stood  at  220  feet. 

An  examination  of  the  diagram,  PL  XIV,  will  show  the  relations  of  the 
two  basins.  There  remains  a  distinct  possibility  that  part  of  this  difi"erence, 
say  about  20  feet,  may  prove  to  be  due  to  a  post-Glacial  elevation  of  the 
western  portion  of  the  area  under  consideration.  The  evidence  of  this  is 
that  the  broad,  flat  delta  plains  in  front  of  the  Chicopee  River  outlet 
at  Collins  Mills,  on  the  east  of  the  basin,  and  of  the  Scantic  Brook,  at 
Scantic,  in  Longmeadow,  are  260  to  265  feet  above  sea,  while  the  corre- 
sponding levels  at  the  head  of  the  delta  of  the  Westfield  are  285  to  290 
feet  above  sea.  The  eastern  streams  cut  thi-ough  glacial  lake  beds  in  their 
upper  waters,  and,  it  would  seem,  should  have  built  out  their  deltas  in  the 
lake  np  to  flood  level. 

THE   SPRINGFIELD   LAKE. 

The  Holyoke  range,  lying  in  the  midst  of  the  Connecticut  Valley  like 
an  inverted  L,  or  like  a  blowpipe,  its  tip  approaching  the  crystalline  border 
of  the  valley  at  the  Belchertown  ponds,  broken  at  its  bend  and  in  the 

MON  XXIX 42 


658  GEOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 

middle  of  its  length  for  the  passage  of  the  Connecticut  and  Westfield  rivers, 
bounds  on  the  north  and  west  the  bed  of  a  third  lake,  which  extended  south 
across  the  borders  of  the  State  to  the  point  where  the  river  enters  the  nar- 
rows at  Middletown.  Its  eastern  boundary  was  the  high  rocky  border  of  the 
valle}^  across  the  towns  of  Belchertown,  Grranby,  Ludlow,  and  Wilbraham. 
The  two  notches  mentioned  above  were  narrow  straits  connecting  this 
lake  with  the  Hadley  Lake,  and  only  a  very  small  portion  of  the  sands  and 
gi-avels  which  now  fill  the  latter  came  through  these  notches  from  the 
northern  lake.  This  was  especially  true  of  the  northern  passage,  for  over 
a  broad  area  in  front  of  it  the  bottom  of  the  Hadley  Lake  was  filled  up 
only  a  few  feet  above  the  present  level  of  the  meadows,  and  that  with  lami- 
nated clays  capped  by  fine  sands,  while  immediately  south  of  the  gorge  the 
sands  are  coarse  and  are  built  up  to  a  plane  100  feet  higher. 

Of  course,  the  narrow  Holyoke  range  on  the  north  and  west  never  fur- 
nished any  considerable  tributary  to  the  lake  after  the  ice  had  disappeared 
from  its  north  and  west  slope,  but  the  ice  melted  away  south  of  the  moun- 
tain much  more  rapidly  then  it  did  north,  and  there  was  a  long  time  when 
bodies  of  water  gathered  upon  the  ice  in  the  northern  area  and  swept 
through  the  notches  in  the  Holyoke  range,  carrying  much  sand  and  gravel 
into  the  southern  basin.  I  have  already  traced  the  watercourse  south  from 
the  Pelham  basin  tln-ough  the  passageway  between  the  east  end  of  the 
range  and  the  crystalline  rocks,  and  tln-ough  the  notch  next  west,  occupied 
by  the  "Bay  road."     (See  p.  588.) 

The  position  of  the  Holyoke  diabase  ridges  detailed  above  had  great 
influence  on  the  action  of  the  ice.  It  plowed  very  deeply  into  the  sand- 
stones north  of  the  main  ridge  in  the  Hadley  Lake,  but  to  the  south  it  left 
the  sandstones  over  much  of  the  basin  above  the  level  afterward  maintained 
by  the  lake.  It  seemed  also  to  plow  in  long  grooves,  leaving  several 
parallel  ridges  of  sandstone,  which  stretch  south  across  Granby  and  South 
Hadley.  These  ridges  may  be  in  part  the  uptilted  western  rims  of  the 
great  fault  blocks  of  the  sandstone.  It  deposited  also  many  great  drumlins 
on  and  in  prolongation  of  these  ridges.  Farther  south  also,  across  Hampden 
.  County,  a  broad  marginal  portion  of  the  basin  is  occupied  by  low  ridges  of 
sandstone  and  till,  which  rise,  for  the  most  part,  but  little  above  the  level 
of  the  lake  sands.  This  had  two  results  of  importance  in  the  history  of  the 
lake:  (1)  So  much  of  the  lake  was  from  the  beginning  shallow  that  its  filling 


THE  SPRINGFIELD  LAKE.  659 

up  did  not  require  neai'ly  so  much  material  as  did  the  much  deeper  Hadley 
Lake ;  (2)  the  great  multitude  of  elevations  make  the  border  of  the  lake  on 
the  east  very  comj^licated. 

The  steep  eastern  Ijorder  of  the  valley  is  notched  for  the  entrance  of 
onl}'  one  tributary  which  heads  back  of  the  first  series  of  ridges.  This  is 
the  Chicopee  River,  which  at  the  village  of  Three  Rivers  gathers  all  the 
drainage  of  eastern  Hampshire  and  Hampden  counties.  In  the  time  of  the 
lake  it  earned  certainlj^  a  much  greater  volume  of  water  than  at  jiresent, 
and  as  the  ramifications  of  this  di-ainage  cover  the  whole  broad  area  of  high- 
level  glacial  lakes  already  described,  their  abundant  sands  furnished  an 
enormous  volume  of  already  sorted  detritus,  which  is  now  spread  in  the 
broad  sand  flats  of  South  Hadley,  Chicopee,  Springfield,  and  Longmeadow. 

The  study  of  the  basin  brought  to  my  attention  several  most  inter- 
esting problems,  and  it  has  been  difficult  to  express  upon  the  map  the 
results  reached.  An  inspection  of  the  map  will  show  that  I  have  there 
represented  the  lake,  in  contradistinction  to  the  two  northern  lakes,  as  a 
nearly  fiUed-up  lake.  In  the  former,  passing  across  the  high  terrace  flat 
toward  the  center  of  the  valley,  one  comes  upon  a  well-marked  scarp  of 
deposition,  or  delta  front,  which  descends  to  the  lower  plane  of  the  lake 
bottom.  Here  one  goes  out  from  the  head  of  the  Chicopee  River  delta, 
264  feet  above  sea,  and  crosses  the  broad,  gradually  sloping  sand  plains  to 
their  inner  edge  overlooking  the  river  meadows  at  240  feet,  or  going  south 
across  Chicopee,  Springfield,  and  Longmeadow,  finds  the  level  sinking  from 
255  feet  in  the  north  to  180  feet  in  the  south;  and  yet  the  whole  great 
sand  body,  the  largest  on  the  river,  covering  a  large  portion  of  four  towns, 
expands  as  a  great,  extremely  flat  "alluvial  cone"  or  delta,  with  imper- 
ceptible slope  from  the  mouth  of  the  gorge  of  the  Chicopee  at  Collins 
depot  to  where  it  is  cut  oif  by  the  later  erosion  of  the  river,  and  shows 
nowhere  any  scai-p  which  could  justify  one  in  separating  the  central  and 
lower  portion  as  lake  bottom  from  the  higher  and  shoreward  portion  as 
lake  shore. 

A  further  inspection  of  the  map  will  show  that  in  the  northern  portion 
of  the  lake  basin  the  deposits  referred  to  the  high  terrace  (1  s  h,  PL 
XXXV,  D)  or  fiUed-up  portion  of  the  lake  are  shaped  rudely  like  a  comb, 
with  its  back  stretching  along  south  of  the  Holyoke  range  and  its  teeth 
extending  south   between  the   long  ridges  of  sandstone   and   till  across 


660       GEOLOGY  OP  OLD  HAMPSHIRE  COUNTY,  MASS. 

Granby  and  South  Hadley  to  blend  with  the  extensive  delta  of  the 
Chicopee  River  last  described..  Starting  at  the  northeast  corner  of  the 
area,  one  can  trace  the  coarse  gravels  of  the  Belchertown  notch  (307  feet 
above  sea)  southwest  continuously  to  the  Grranby  line,  in  a  band  about  50 
rods  wide,  resting  against  sandstone  on  the  north  and  till  on  the  south,  like 
a  river  course,  the  coarse  gravels  of  the  notch  (6  inches)  becoming  gradu- 
ally finer,  at  the  town  line  consisting  of  a  1-  to  2-inch  gravel.  Just  here 
the  band  expands  westward  and  southward  in  the  broad,  perfectly  hori- 
zontal Granby  plain  of  fine  sand,  which  extends  south  with  nearly  half 
the  full  width  of  the  town,  and  west  as  a  much  narrower  band,  sending  ofP 
a  long  lobe  south  on  the  east  side  of  Granby  Hill,  and  another  broader 
lobe  west  of  the  same  hill,  which  starts  south  with  a  bottom  of  6-inch 
gravel  (at  266  feet  above  sea)  but  grows  finer  as  it  goes  south. 

The  deposits  extend  still  farther  west  and  grow  still  narrower  just  south 
of  the  notch  of  the  Holyoke  range,  where  the  waters  seem  for  a  little  way  to 
have  passed  over  the  bare  sandstones,  and  they  then  expand  into  the  broad 
sand  plain  of  Moody  Corners  (in  the  wood  road  running  north  from  the 
Corners  fine  cross-bedded  sands  are  exposed,  above  30  feet  thick),  which 
extends  west  across  the  north  of  South  Hadley,  sending  several  other  lobes 
southward.  We  have  here  two  elements,  diverse  in  character  and  origin, 
which  together  form,  I  believe,  the  bottom  deposits  of  the  lake:  to  the  north 
are  the  coarse  gravels  which  have  plainly  come  through  the  Belchertown 
notch  and  been  swept  southward  by  a  strong  current  in  the  many  lobes 
just  described,  and  to  the  south  is  the  enormous  body  of  the  sands  of  the 
Chicopee  River  delta  described  above. 

Southward  the  lobes  of  the  northern  deposits  blend  with  the  sands  of 
the  southern  deposit  at  a  common  level  without  the  intervention  of  any 
scarp  which  could  indicate  difference  of  age  between  the  two  deposits; 
and  this  is  the  basis  of  the  decision  indicated  above — that  they  are  strictly 
synchronous  and  together  form  the  flood  deposit  of  the  Springfield  Lake. 

A  further  and  most  interesting  conclusion  is  that  the  floods  of  the 
northern  basin  continued  for  a  long  time  to  pass  across  the  Belchertown 
notch  into  the  southern  basin  after  the  latter  was  fully  abandoned  by  the 
ice,  although  (1)  the  level  of  the  sands  in  the  Belchertown  notch  is  about 
40  feet  above  the  level  of  the  high  terrace  of  the  lake  to  the  north,  and  (2) 
the  abundant  kettle-holes  show  that  the  water  ceased  to  pass  through  the 
notch  before  the  ice  had  melted  out  from  below  the  sands  spread  there. 


THE  GORGE  TERRACE  OP  DRY  BROOK  HILL.  661 

In  coiincctioii  with  the  second  pomt,  we  may  call  to  mind  (see  p.  718) 
tlint  iirctii'  pliints  are  fomid  in  the  clays  of  the  Hadley  Lake  to  their  top; 
this  indiciites  a  cold  climate  at  an  even  later  time  than  the  one  contemplated 
here,  which  would  permit  the  ice  to  remain  buried  almost  indefinitely. 

As  to  the  first  point,  the  area  covered  by  the  gravels  in  question,  except 
toM-ard  the  west,  beyond  Moody  Comers,  was  left  filled  nearly  to  the 
present  level  by  the  ice,  and  a  great  body  of  gravel  was  swept  into  this  area 
through  tlie  notches  of  the  Holyoke  range,  and  last  of  all,  the  last  floods 
passing  through  the  Belcliertown  notch  spread  these  gravels  and  carried 
them  south  and  blended  them  with  the  finer  contributions  of  the  Chicopee 
Eiver.  It  does  not  seem  improbable  that  floods  rising  40  feet  above  the  level 
of  the  confluent  deltas  of  the  Hadley  Lake  m&j  have  occurred  many  times, 
even  after  the  ice  had  retreated  wholly  from  this  lake  basin;  but  it  seems 
more  probable  that  the  southern  basin  was  set  free  from  the  ice  so  long 
before  the  northern  that  the  operations  here  under  consideration  had  been 
in  the  main  completed  before  the  ice  finally  retreated  from  the  greater 
portion  of  the  Hadley  basin.  I  may  refer,  also,  to  the  proofs  of  a  readvance 
of  the  ice  in  this  basin  given  below. 

A  further  consideration,  to  which  we  now  turn,  will  show  that  the  floods 
through  the  Belcliertown  notch  continued  until  after  the  ice  had  set  free  the 
Holyoke  notch,  through  which  the  river  now  runs. 

THE  "GORGE  TERRACE"  OF  DRY  BROOK  HILL,  SOUTH  OP  HOLYOKE  NOTCH,  IN 
THE  NORTH  PART  OF  SOUTH  HADLEY. 

The  terrace  of  Dry  Brook  Hill,  in  South  Hadley,  is  the  most  remark- 
able terrace  in  the  valley,  and  was  the  type  of  a  class  in  President  Hitch- 
cock's classification  of  terraces.^  If  the  deposits  removed  by  the  erosion  of 
the  brooks  in  the  north  of  Granby  and  South  Hadley  be  restored  in  imagi- 
nation, what  seems  an  old  river  course  may  be  followed  tlu"Ougli  the  Belclier- 
town notch  and  along  south  of  the  Holyoke  range — and  it  was  held  to  be 
an  old  river  bed  by  President  Hitchcock^ — until  just  south  of  the  Mountain 
House  it  bends  south  on  a  great  drumlin  southwest  of  Moody  Corners  and 
then  runs  south  as  a  well-defined  river  channel,  skirting  this  hill  on  the  east 
and  bounded  on  the  west  by  the  marked  construction  escarpment  of  a  long 
flat-topped  hill  of  coarse  stratified  sand,  the  Dry  Brook  Hill,  which,  abutting 

'  Surface  Geology,  p.  .5. 

^  (Jeminiacences  of  Amherst  College,  p.  279,  and  map. 


662       GEOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 

on  the  north  against  the  shoulder  of  the  mountain,  runs  south  nearly  a  mile. 
Groing  up  35  feet  to  the  top  of  this  hill,  one  is  surprised  to  see  that  on  the 
west  it  slopes  suddenly  down  190  feet  to  the  river  which  is  wearing  at  its 
foot.  The  escarpment  on  the  east  which  borders  the  channel  is  plainly  a 
scarp  of  deposition,  and  the  whole  terrace  was  possibly  built  by  the  rapid 
current  through  the  Holyoke  notch,  meeting  the  current  we  have  traced 
from  the  Belchertown  notch  and  allowing  the  sands  to  gather  ij_.  a  bar  in  the 
slack  water  between  the  two.  Perhaps  it  should  be  assigned  to  a  slightly 
earlier  period,  when  the  ice,  still  abutting  on  the  Holyoke  range  to  the  north, 
projected  through  the  notch  and  allowed  the  sands  to  gather  against  its 
eastern  flank  and  on  melting  let  them  cave  to  form  the  passage  for  the  river. 
The  presence  of  the  ice  on  the  north  spanning  the  Holyoke  notch  is  essen- 
tial to  the  formation  of  this  great  terrace  of  coarse  material,  because  since 
the  ice  disappeared  nothing  but  tine  clay  has  been  brought  by  the  waters 
into  the  gorge  from  the  north,  while  the  section  which  treats  of  the  glacial 
gravels  carried  through  the  notches  in  this  range  (p.  586)  furnishes  a  clear 
explanation  for  this  abnormal  deposit. 

HIGH  TERRACE  OR  BENCH  OF  THE  WEST  SIDE  OP  THE  LAKE  FROM  THE  HOLYOKE 

NOTCH  SOUTHWARD. 

From  the  notch  to  "the  north  line  of  the  town  of  Holyoke  the  ground 
rises  rapidly  from  the  narrow,  low  terrace  up  a  rocky  slope  to  the  crest  of 
the  eastern  trap  ridge,  and  there  is  scarcely  trace  of  any  high  terrace  upon 
its  flank,  because  there  was  deep  water  in  the  Hadley  Lake  opposite  the 
mouth  of  the  notch  and  little  sand  was  brought  through  here.  What  was 
brought  stretched  south  in  a  great  bar  which  is  almost  intact  on  the  other 
side  of  the  river,  in  Dry  Hill,  in  the  north  part  of  South  Hadley,  just 
described,  as  can  be  beautifully  seen  from  the  inner  trap  ridge  mentioned 
above.  All  that  passed  through  the  notch  on  its  west  side  was  swept  in 
between  the  two  trap  ridges  and  filled  a  bay  north  of  the  burnt  stone  mill 
above  Smiths  Ferry.  All  along  the  riverward  flank  of  the  east  trap  ridge 
high  sands  were  not  laid  down  because,  for  this  portion  of  the  basin,  the 
supply  came  from  the  far-off  east  side,  mainly  from  the  Chicopee  River,  and 
as  the  deposit  expanded  westward  its  level  lowered,  so  that  no  high  terrace 
sands  were  brought  against  the  till-covered  trap  slope,  and  the  small  inden- 
tation made  by  the  waters  at  this  level  has  left  no  trace  of  its  presence. 


THE  BELCnEKTOWN  AND  MOUNT  TOBY  NOTCHES.  663 

Just  at  the  north  hue  of  Holyoke  the  eastern  trap  ridge  sinks  below 
the  level  of  the  lake,  and  over  most  of  the  town  a  great  body  of  till  rises 
luiu'li  above  its  level,  and  in  this  the  lake  cut  back  a  broad  terrace  flat,  and 
where  these  drift  deposits  sank  below  the  level  of  the  lake  the  latter  spread 
its  sands  broadly  across  Holyoke  and  West  Springfield.  From  the  north 
line  of  Holyoke  the  influence  of  the  great  body  of  sand  sent  clear  across 
the  basin  from  the  Chicopee  River  becomes  apparent,  and  although  there 
was  no  drainage  down  the  trap  slope  on  the  west,  and  the  till  beneath  was 
very  largely  made  up  of  Triassic  shale,  the  gneissic  sands  from  the  east  of 
the  basin  extend  out  over  the  till  along  the  line  indicated.  They  bring  a 
broad  area  nearly  up  to  the  level  of  the  high  terrace,  because  it  was  quite 
near  that  level  before;  and  south  of  the  Westfield  River,  in  Agawam,  the 
terrace  expands  to  nearly  the  width  of  the  town,  largely  for  the  same 
reason.  It  was  here,  of  course,  somewhat  reenforced  by  material  brought 
through  the  notch  of  the  Westfield  River,  but  I  question  if  much  came  that 
way,  as  the  source  of  the  supply  in  the  Westfield  basin  was  across  on  the 
west  side,  and  the  sands  were  in  the  main  swept  south.  I  think  more  came 
south  over  Ashley's  pond  and  west  from  the  Chicopee  River,  and  that  the 
diff'erence  of  level  of  the  high  terrace  here  and  in  the  Westfield  basin  is 
almost  wholly  owing  to  a  deficit  of  material  in  Agawam  and  West  Spring- 
field. Toward  the  river  in  Agawam  the  sands  come  to  be  of  great  volume, 
and  they  once  extended  across  to  meet  those  of  Longmeadow,  and  the  lake 
was  in  this  part  well  filled  up  when  the  recession  of  its  waters  began. 

THE    SIMILARITY    OF    THE    BELCHERTOWN    NOTCH   TO   THE   NOTCH  EAST   OP  MOUNT 

TOBY. 

I  have  already  shown  (p.  584)  how  the  ice  in  the  Montague  basin, 
abutting  against  the  eastern  margin  of  the  basin  and  against  the  northeast 
shoulder  of  Mount  Toby,  turned  the  waters  of  the  Locks  Pond  Brook  south 
into  the  gorge  between  Mount  Toby  and  the  high  ridge  of  crystalline  rocks 
in  the  west  portion  of  Leverett,  and  how  these  waters  cut  a  watercourse, 
still  well  defined,  through  the  gorge  and  sent  out  a  broad  delta — the  present 
South  Leverett  plain — into  the  Hadley  basin.  Just  so  the  waters  of  the 
Pelham  brooks  flowed  south  from  the  Hadley  basin  into  the  Springfield 
basin  through  the  Belchertown  notch  and  spread  the  long  reaches  of  sand 
westward  down  the  present  course  of  Bachelors  Brook  and  south  to  Ludlow 
Mills. 


664       GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

THE  MOEAINE  ACROSS  THE  SOUTHERN  PART  OF  THE  GRANBY  PLAIN. 

Nortli  of  Ludlow,  in  the  south  part  of  Grrauby,  is  a  plain  about  a  mile 
square.  It  is  the  south  end  of  the  great  Granby  plain,  and  is  bounded  on 
the  east  by  the  valley  rim  and  on  the  west  and  south  by  elevated  ridges  of 
till,  which  at  the  southwest  corner  leave  open  a  narrow  passage  by  which 
one  passes  from  this  plain  out  onto  the  broader  plain  of  finer  sand  that 
extends  down  to  the  Chicopee  and  across  west  to  the  Connecticut  River. 
A  brook  has  occupied  this  narrow  gateway,  and  its  flood  plain  is  just  wide 
enough  to  render  it  slightly  uncertain  whether  the  larger  plain  formerly 
extended  continuously  through  and  joined  the  inner  plain  at  a  common 
level.  The  difference  in  level,  if  any  exists,  is  very  slight,  and  the  inner 
plain  is  at  its  south  end  about  260  feet  above  sea — a  level  plain  of  medium- 
grained  sand.  Fifty  rods  north  the  sand  changes  to  a  2-inch  gravel,  in 
another  50  rods  to  a  3-inch  gravel,  in  the  same  distance  again  to  a  4-inch 
gravel;  and  it  has  risen  in  this  distance  to  298  feet.  It  preserves  its  even 
surface  for  another  50  rods,  and  then  suddenly  drops  down  into  a  series  of 
great  kettle-holes,  which  continue  a  hundred  rods  and  end  against  a  moraine 
(t  m)  that  stretches  right  athwart  the  plain  from  east  to  west,  not  reaching 
its  border  on  either  side.  It  is  unlike  any  other  deposit  in  the  valley,  and 
seems  exactly  like  a  terminal  moraine.  The  sands  swing  round  it  on  either 
side  and  extend  north,  with  here  and  there  a  depression,  but  much  more 
regular  than  immediately  south  of  the  moraine.  I  can  not  quite  understand 
this,  or  its  time  relation  to  the  lake  sands,  but  have  expressed  on  the  map 
the  most  probable  solution  of  the  matter. 

KETTLE-HOLES  AND  THE  OLD  BED  OP  THE  CONNECTICUT. 

As  a  result  of  the  fact  that  about  all  the  material  which  went  to  fill  up 
the  lake  came  from  the  east  side,  at  the  beginning  tln-ough  the  Belchertown 
notch,  later  from  the  Chicopee  River,  the  Connecticut  found  itself  pressed, 
on  the  shrinkage  of  the  lake,  to  its  western  border;  and  it  has  excavated  its 
channel  so  near  that  border  that  from  Smiths  Ferry  to  Holyoke  there  is 
only  a  trace  of  the  lake  deposits  left  on  the  west  of  the  present  stream ;  and 
in  all  this  distance  the  river  has  cut  a  new  bed  down  into  the  sandstone, 
while  across  Chicopee  it  has  cut  its  bed  largely  in  till.  (See  PL  XI,  p.  610.) 
Its  present  bed  seems  to  coincide  with  the  old  one  nearly  down  to  Smiths 


KETTLE-HOLES.  665 

Ffrr\-,  since  no  rock  crops  out  in  the  l)ank  up  to  that  point.  From  here  I 
iniiU'-iue  that  the  old  livcr  ran  soutlieast  across  South  IliuUoy,  then  across  a 
corner  of  ('hii-o])ee  and  Ludlow  to  Indian  Orchard,  foUowing  the  band  of 
l)rook  Ijeds  and  ponds  which  can  be  traced  along  this  line,  especially  in 
Ludlow,  then  following  the  marked  line  of  kettle-holes  which  extend  a 
little  west  of  south  from  Indian  Orchard  across  Springfield,  to  join  its 
present  course  not  far  from  the  north  line  of  Longmeadow.  This  line  of 
kettle-holes  can  be  traced  by  the  line  of  ponds  on  the  map,  and  is  espe- 
cially marked  in  the  northern  part  of  the  line  and  for  a  long  distance  south 
across  Springfield,  Avhere  the  otherwise  unbroken  level  of  the  enormous  sand 
wastes  is  broken  by  a  great  number  of  these  depressions,  many  of  the 
largest  size,  and  only  here  and  there  is  one  pei'manently  tilled  with  water. 
I  imagine  that  remnants  of  ice  ling-ering-  longer  in  portions  of  the  old  river 
bottoms  were  submerged,  and  remained  until  the  climate  ameliorated. 

KETTLE-HOLES  AND  THE  STRUCTURE  OF  THE  HIGH  TERRACE  SANDS;   THEIR 
ORIGIN  FROM  THE  MELTING    OF  ICE  BENEATH  THE  TERRACE  GRAVELS. 

The  distribution  of  kettle-holes  is  given  in  connection  with  the  descrip- 
tion of  the  lower  glacial  lakes  and  of  the  high  terrace  or  shore  of  the 
Connecticut  lakes.  The  principal  areas  are  (1)  along  the  outer  portion  of 
the  high  terrace  in  West  Northfield  and  stretching  through  the  Bernardston 
Pass;  (2)  in  Northampton;  (3)  across  the  high  Montague  plain  south  of 
Millers  Falls  and  along  the  flanks  of  the  Pelham  Hills  and  through  the 
Belchertown  Pass,  in  sands  of  the  lowest  glacial  lake;  (4)  across  the 
Chicopee-Springfield  basin. 

Continuous  railroad  sections  have  given  me  exceptional  opportunity  to 
study  them,  and  have  convinced  me  that  the  explanation  of  their  origin 
accepted  by  many  geologists  is  the  true  one,  viz:  That  they  are  formed  by 
the  sinking  of  tile  sands  from  the  melting  away  of  ice  which  has  been 
buried  beneath  them.  They  range  from  small  shallow  depressions,  grouped 
together  over  sand  plains  elsewhere  quite  horizontal,  to  deep  sink-holes  with 
sides  as  steep  as  sand  will  lie,  and  without  outlet,  isolated,  or  so  crowded 
that  they  are  separated  only  by  narrow  ridges,  and  merging  thus  into  broad 
sunken  areas  with  irregular  ridgy  surface. 

The  inner  structure  of  the  sands  in  the  neighborhood  of  the  kettle- 
holes  increases  in  complexity  and  irregularity  as  the  holes  increase  in  size 


666       GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

and  approach  nearer  to  each  other,  and  where  they  merge  in  "reticulate 
ridges"  this  complexity  becomes  extreme. 

In  a  continuous  section  through  a  plain  abounding  in  kettle-holes  new 
ones  came  to  light  which  are  not  indicated  by  any  depression  on  the  sur- 
face, they  having  been  formed  and  filled  before  the  completion  of  the 
plain.  In  other  cases  this  filling  has  been  partial,  and  in  every  degree,  so 
that  a  very  slight  depression  upon  the  surface  may  indicate  an  extensive 
disturbance  of  the  beds  below.  ' 

In  cases  where  the  lamination  of  the  sands  is  very  regular  and  hori- 
zontal the  beds  sink  down  on  approaching  a  kettle-hole,  with  little  disturb- 
ance where  the  bending  is  slight;  where  it  is  considerable  they  dip  inward 
from  all  sides  with  a  series  of  small  faults ;  where  the  subsidence  is  extreme 
they  are  thrown  into  complete  confusion;  where  they  are  wholly  or  partly 
filled  the  upper  layers  thicken  downward  to  fill  the  depression,  and  have 


Fig.  40. — Section  soutli  of  Millers  Falla  station  to  show  kettle-holes  formed  by  ice  melting  from  beneath  the  sands. 

often  a  different  structiu'e  in  the  depression  from  that  outside,  generally  a 
strong  cross-bedding  dipping  in  the  direction  of  the  current,  which  shows 
that  the  sinking  took  place  somewhat  suddenly  and  the  next  flood  found 
and  filled  the  depression  rapidly.  Where  the  whole  thickness  of  the  sand 
was  exposed  I  found  it  in  one  series  resting  upon  a  glacial  surface  of 
gneiss  and  trap  without  the  intervention  of  clay,  which  might  have  made 
place  for  the  sinking  in  of  the  sands  by  lateral  flow,  as  has  been  suggested; 
nor  is  there  any  indication  of  a  lateral  movement  of  the  sands  out  from 
under  the  sunken  areas,  as  I  have  seen  them  undisturbed  and  horizontal  on 
all  sides  as  the  broad  cutting  removed  the  whole  kettle-hole. 

These  depressions  are  found  only  in  the  lake  bench  or  in  the  still 
higher  glacial  lake  beds,  and  are  frequent  in  places,  as  in  the  center  of  broad 
sand  plains,  where  local  eddies  would  be  supposed  to  be  least  effective. 
Indeed,  their  great  depth,  great  extent,  very  steep  sides,  and  irregular  distri- 
bution would  make  it  difficult  to  explain  them  in  this  way.     On  the  other 


KETTLE-HOLES.  667 

hand,  all  tlu'ir  i)C'Ouliaritie.s  seem  to  me  to  find  abundant  explanation  in  the 
assumption  that  renniants  of  the  ice  became  covered  by  the  sands,  and  in 
tlu'  then  low  temperature  remained  often  for  a  long  time,  as  in  the  arctic 
countries  to-day;  and  as  my  knowledge  of  the  region  has  become  more 
extensive  I  have  found  more  and  more  evidence  of  the  presence  of  ice  still 
in  the  valley  during  the  building  of  the  high  terrace. 

The  accompanying  figures  show  in  detail  the  facts  summarized  in  the 
preceding  paragraphs.  They  are  selected  from  a  much  larger  number,  and 
were  in  part  drawn  with  the  thermometer  much  below  zero  and  are  given 
just  as  they  were  made. 

In  fig.  40,  showing  the  long  section  on  the  New  London  Northern 
Railroad  extending  south  from  the  station  at  Millers  Falls  and  taken  from 
the  east  wall  of  the  cutting,  the  upper  layer  is  a  coarse  gravel  5  to  7  feet 
thick,  coarsest  and  thickest  at  the  north  end  of  the  section,  where  it  is  nearest 
the  source  of  su.pply  at  the  head  of  the  delta.  Beneath  this  are  fine  white 
sands  which  run  in  thick  sheets  horizontally  for  long  distances,  the  sheets 
showing  the  finest  false  bedding*.  It  is  perfectly  plain  that  the  gravels  were 
laid  down  on  a  horizontal  surface  of  the  fine  sands,  and  that  these  were 
thrown  down  in  horizontal  sheets,  and  that  the  sink-holes  are  of  later  origin. 

At  1  in  the  figure  is  the  beginning  of  the  cutting  just  below  the  station. 
It  is  the  southern  border  of  an  irregular  sunken  area  that  sends  lobes  east 
nearly  to  the  rocks.  The  fine  sands  sink  gradually  below  the  surface,  and 
the  great  thickening  of  the  gravels  may  be  due  in  whole  or  part  to  a  sinking 
of  the  sands  before  the  whole  of  the  gravels  were  tln'own  down. 

At  2  the  sinking  of  the  under  sands  is  accompanied  by  a  series  of 
small  parallel  faults,  dipping-  inwardly  from  the  irregular  sinking,  and  the 
gravel  thickens  downward,  partly  filling  the  depression.  At  3  is  a  wholly 
submerged  sink-hole,  the  sands  bending  down  and  the  gravels  thickening 
down  to  fill  the  space,  showing  that  the  ice  melted  away  before  the  deposi- 
tion of  the  upper  beds.  At  4  and  5  this  is  repeated.  At  6  is  a  fine  kettle- 
hole,  and  marked  faults  dipping  inward  from  both  sides,  accompanied  by 
a  great  number  of  smaller  faults  with  throw  iii  the  same  direction.  At  7 
the  faults  are  complicated,  as  if  by  gradual  melting  a  new  substratum  had 
several  times  been  produced  during  the  building  up  of  the  sands. 

In  the  lower  figure  is  shown  the  other  side  of  the  cutting,  so  that  the 
two  views  face  each  other,  as  shown  by  the  cross  section.     Here  the  kettle- 


668 


GEOLOGY  OP  OLD  HAMPSHIEE  COUNTY,  MASS. 


hole  (7)  was  much  wider  and  only  the  northern  border  is  drawn,  showing 
the  horizontal  sands  breaking  off  abruptl}^  and  sands  with  steep  southward 
dip  carried  in  to  fill  the  cavity.  The  outcrops  of  trap  and  gneiss  covered 
with  glacial  stria3,  at  the  base  of  this  section,  show  that  the  sands  extend 
down  to  the  rock,  and  that  no  clay  exists  below  them  which  might  by  lateral 
flow  have  allowed  the  subjacent  sands  to  sink  down.  Indeed,  as  the  section 
is  cut  in  the  center  of  a  great  sand  plain,  such  a  supposition  is  plainly 

excluded. 

At  8  begins  a  general  sinking  of  a  broad  area;  at  9  an  earlier  and  more 
rapid  sinking  of  a  limited  area,  which  was  filled  with  gravels  that  are 
finely  cross-bedded  with  southeriy  dip,  showing  that  they  were  carried  into 
the  depression  by  a  current  from  the  north.  Just  below  this  point  the 
New  London  Northern  and  the  Fitchburg  railroads  separate,  and  at  the  first 
cutting  below  the  point  of  separation  on  the  Fitchburg  road  the  depression 


10  FEET 

Fig.  41.-Seotion  south  of  Millers  FaUs  to  show  kettle-liole  fonued  by  ice  stranded  on  the  surface  of  the  sands. 

represented  in  fig.  41  was  cut  across,  which  is  here  given  in  order  to  contrast 
a  cavity  produced  plainly  by  the  stranding  of  floating  ice  with  the  sink-holes 
under  discussion. 

The  horizontal  sands  come  toward  the  cavity  undisturbed  from  either 
side,  and  at  a  certain  distance  below  retain  their  horizontality  beneath  it. 

Down  the  slope  on  the  north  side  the  sands  are  bent  down  and  the 
layers  are  combed  over  and  disarranged,  ending  abruptly  at  the  surface  of 
the  cavity.  Below  the  south  side  they  are  squeezed  together  and  finely 
corrugated.  A  thin  layer  of  gravel  appears  thickened  and  irregular  in  the 
bottom  of  the  cavity  and  discontinuous  on  its  southern  side.  The  whole 
was  filled  with  a  fine  unstratified  loess,  whether  wind-  or  water-brought  is 

uncertain. 

Farther  west,  across  the  middle  of  the  great  Montague  plain,  runs  the 
line  of  large  water-filled  kettle-holes  already  mentioned  as  indicating  the 


KETTLE-HOLES. 


6G9 


probable  position  of  tlie  old  bed  of  tho  Connecticut.  The  great  southward 
bend  of  Millers  River  extends  into  this  line  for  a  distance,  and  the  stream 
wore  freeh'  in  this  direction,  because  from  the  depth  of  the  old  channel 
it  found  hero  ni.)  rock  to  obstruct  it,  while  all  around  the  rock  rises  to  a 
niucli  o-reater  level. 

A  depression  in  the  plain  connects  this  basin  with  the  great  kidney- 
shaped  Green  Pond,  with  banks  30  feet  high,  as  steep  as  sand  will  lie,  and 
with  about  25  feet  depth  of  water.  On  the  south  the  bank  breaks  down 
and  a  low  col  connects  it  with  the  much  larger  pond,  Lake  Pleasant,  with 
similar  banks  and  a  depth  of  water  of  37  feet,  as  measured  for  me  by  Mr. 
F.  A.  Pugg,  a  former  piipil.  From  its  south  end  runs  a  depression  whose 
contom-s  have  been  changed  by  the  brook  which  runs  in  it  and  drains  the 
lake. 

In  Belchertown  the  sections  made  by  the  Central  Raih'oad  cut  through 


Fig.  43 Section  of  north  half  of  a  kettle.hole  below  D  wight's  station  on  the  Central  Eallroad,  Belchertown. 


many  interesting  kettle-holes  north  and  south  of  the  Belchertown  ponds, 
which  ponds  themselves  belong  to  the  same  class  of  sink-holes.  They 
belong  to  the  deposits  of  the  Pelham  River  (see  p.  588),  and  are  thus  of 
slightly  greater  age  than  the  foregoing. 

Fig.  42  gives  a  sketch  of  a  portion  of  the  second  cutting  below  Dwight's 
station  at  the  "  Big  Fill."  It  is  carried  along  the  slope  of  the  terrace,  and 
the  jagged  line  in  the  middle  of  the  figure  is  explained  by  the  fact  that  the 
cut  of  the  New  London  Northern  Railroad  is  just  east  of  and  parallel  to 
this  and  the  crest  caved  between  them,  so  that  only  a  few  of  the  telegraph 
poles  remained. 

The  cutting  showed  the  cross  section  of  two  submerged  kettle-holes. 
The  heavy  line  commencing  at  a  is  the  surface  of  the  sink-hole,  and  it  is 


670 


GEOLOGY  OP  OLD  HAMPSHIEE  COUNTY,  MASS. 


strongly  marked  by  iron  rust.  From  the  north  the  heavy  horizontal  pinkish 
sands,  underlain  by  equally  heavy  cross-bedded  sands,  both  of -medium 
grain,  come  for  a  long  distance,  and  at  a  they  commence  to  sink  down,  and 
seem  to  have  sunk  so  evenly  and  on  so  smooth  and  regular  a  substratum  that 
they  were  stretched,  and  a  great  number  of  minute  fisstires,  all  about  nor- 
mal to  the  bedding,  were  formed — fissures  so  minute  that  they  would  have 
escaped  attention  if  they  had  not  been  colored  by  infiltrated  iron  rust.  A 
few  slight  faults  dipping  inwardly  Avere  also  formed.  They  are  unduly 
emphasized  from  their  coloring  with  rust.  Finer,  pale-bufi",  loamy  sands 
rest  in  this  depression  and  gradually  fill  it,  the  sheets  being  poured  OA^'er  its 
northern  edge  and  thickened  below  and  separately  cross-bedded. 

Farther  south,  at  the  south  end  of  North  Pond,  the  whole  of  a  good- 
sized  kettle-hole  was  removed,  and  fig.  43  would,  with  small  modification, 


Tig.  43.— Section  at  the  south  end  of  North  Pond,  BelchertoTvn,  showing  part  of  a  kettle-hole  at  the  north  end  and  of  an 

erosion  slope  at  the  south  end. 

represent  any  radial  section  through  it.  At  the  north  end  is  seen  the 
quarter  of  the  kettle-hole,  with  coarse  sand  and  gravel  beds  above  and  fine 
cross-bedded  sands  below,  and  both  sink  with  a  series  of  small  faults  from 
their  normal  position  down  to  form  the  regular  bowl-shaped  depression.  On 
the  south  the  beds  are  cut  ofl^  by  erosion.  An  old  torrent  bed  runs  across 
the  plain  at  this  point,  and  the  contrast  between  the  two  slopes  is  striking. 
Interesting  sections  were  exposed  in  the  great  cutting  of  fine  sand  at 
the  north  end  of  the  filling  of  the  Central  liailroad  south  of  D wight's  station 
(called  the  "Big  Fill"  by  the  engineers).  This  cutting  was  in  the  terrace 
connecting  the  sands  spread  through  the  Belchertown  Pass  with  the  great 
delta  sent  out  by  Pelham  River  just  north  of  Dwight's  station.  (See  p.  588.) 
When  this  terrace  was  deposited  the  ice  formed  the  westeru  banli  against 
which  it  rested,  and  when  the  ice  had  melted  back  a  little  the  delta  just  men- 
tioned was  sent  out  into  the  temporary  lake  thus  formed,  which  occupied  the 
corner  of  the  basin  in  which  Dwight's  station  now  lies.     The  surface  of  this 


KETTLE-HOLES.  671 

tt'iTiu-f  is  :il)i>nt  40  feet  above  the  lii<ili  terrace  or  bench  of  the  Connecticut 
Lake.  Ill  the  eastern  wall  fine,  })inkish  sands,  with  regular  structure,  indi- 
cating- a  steady  southward  current,  tbrin  the  lower  and  larger  portion  of 
the  sectidu.  Fig.  44  is  drawn  from  the  west  w^all  of  this  cutting,  about  46 
feet  farther  west  than  the  t)ther,  and  it  is  interesting  to  see  the  marked 
contrast  between  the  two.  Except  for  two  small  kettle-holes,  the  eastern 
section  is  A-ery  regular,  while  the  western  is  extremely  disturbed.  The 
sands  belo\\'  the  line  a  are  the  fine,  pinkish,  granitic  sands  of  the  lower  portion 
of  the  opposite  section,  and  these  have  sunk  down  irregularly  and  have 
been  much  eroded,  and  in  all  the  southern  portion  of  the  section  haA'^e  gone 
entirely  below  its  level.  They  are  covered  by  the  finer,  loamy  sands,  with 
much  more  irregular  and  shifting  (fiow-and-plunge)  structure,  and  are  tor- 
tuous and  contorted  throughout  the  whole  extent  of  the  exposure,  295  feet 
(only  a  small  portion  drawn),  in  a  manner  which  would  harmonize  well  with 


FlQ.  44.— Section  of  kame  sands  at  the  north  enJ  ol  the  "Big  Fill     south  of  D-vMght  s. 

the  proposed  explanation  that  they  were  deposited  against  and  upon  a 
shifting  and  inconstant  wall  of  ice. 

The  west  and  south  walls  of  the  "borrow"  south  of  the  "Big  Fill," 
at  the  entrance  of  the  Belchertown  Pass,  from  which  material  was  ' '  bor- 
rowed "  for  the  latter,  was  an  example  of  a  region  where  the  kettle-holes 
are  closely  approximated,  and  represent  the  work  of  the  violent  current  of 
the  Pelham  River  in  the  presence  of  shifting  ice.  The  whole  south  wall 
showed  the  finest  flow-and-plunge  structure,  whose  direction  made  it  seem 
most  probable  that  the  current  came  over  the  ice  from  the  northwest.  The 
other  walls  showed  the  most  rapid  alternations  of  coarse  and  fine  beds,  of 
cross-bedding,  and  of  shifting  and  confusion  from  the  repeated  sinking  of 
the  ice  beneath  beds  already  formed. 

Finally,  an  example  may  be  taken  from  a  "borrow"  along  the  east 
side  of  the  New  London  Northern  Railroad  south  of  the  overhead  bridge 
south  of  North  Amherst  station,  showing  the  extreme  of  complexity  of 
an  area  of  "reticulated  ridges,"  where,  although  the  action  of  water  is 
manifest  throughout,  the  deposit  might  almost  be  called  a  moraine,  as  the 


672  GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

action  of  ice  is  almost  as  clear  as  tliat  of  water.  It  is  a  "  moraine  terrace," 
as  these  kettle-holed  plains  were  called,  with  wonderful  aciiteness,  by 
President  Hitchcock.^  I  subjoin  my  notes  of  the  section  as  taken  July  30, 
1880: 

A  perfectly  though  very  rudely  and  confusedly  stratified  bank  makes 
the  upper  stratum,  commencing  at  the  surface  as  coarse  sands  in  rapid 
alternations  of  grade  and  pretty  regularly  horizontally  bedded,  but  below 
filling  up  hollows  in  the  next  lower  bed,  and  in  places  there  is  quite  fine 
sand  in  the  bottom  of  the  hollows.  The  whole  is  about  10  feet  thick  at 
maximum. 

Next  below  is  a  single  stratum  of  coarse  gravel  about  3^  feet  thick, 
pebbles  mostly  between  three-fourths  and  1  inch,  but  going  up  to  1^ 
inches.  This  has  certainly  been  pushed  in  all  at  once  in  an  overloaded 
flood  current,  and  has  gouged  into  the  stratum  of  sand  below,  gathering  it 
up  here  and  there  in  folds  and  in  other  places  blending  it  with  its  own 
material. 

Next  below  are  the  remains  of  a  sand  stratum,  in  its  upper  portion  fine 
sand,  in  places  well  washed,  and  1  to  3  feet  thick,  or  in  alternations  of  fine 
and  coarse  sands,  the  latter  also  well  sorted,  the  whole  stratum  nearly  7 
feet.  This  graduates  below  into  a  coarse  gravel,  made  up  for  the  most 
part  of  pebbles  three-fourths  of  an  inch  long,  of  which  1 0  feet  are  exposed. 

It  is  noticeable  that  the  great  majority  of  the  lai'gest  bowlders  are 
thoroughly  rounded,  especially,  the  quartz  bowlders,  and  many  are  hard, 
far-traveled  rocks,  while  side  by  side  with  these  are  many  not  worn  at  all, 
and  in  one  case  I  found  a  well-scratched  glacial  bowlder. 

The  great  angular  masses  of  the  coarse  Moiint  Toby  conglomerate 
are  more  than  3  feet  on  a  side.  South  of  the  cutting  a  bowlder  of  conglom- 
erate 9  feet  across  lies  on  the  surface  of  the  "  moraine  terrace,"  and  a  peculiar 
mound  rises  above  its  general  surface  12  to  16  feet. 

LAKE  BOTTOMS. 
THE  BOTTOM  OP  THE  MONTAGUE  LAKE. 

From  the  high  terrace  or  lake  bench  (1  s  h,  PI.  XXXV)  one  passes  down 
over  a  scarp  of  deposition,  not  of  erosion,  to  the  corresponding  and  syn- 
chronous lake  bottom  (Ibt).     This  scarp  is  quite  generally  well  marked, 

'  Surface  Geology,  1860,  p.  33. 


THE  HADLEY  LAKE  BOTTOM.  673 

especially  opposite  the  entrance  of  streams.  At  times,  liowever,  especially 
where  the  water  stood  against  older  sand  deposits  and  where  there  was  little 
current,  a  very  gradual  slope  goes  down  to  the  lake  bottom  from  the  old  water 
surface  notched  in  these  sands,  and  no  sharp  line  of  demarcation  exists. 

In  the  northern  part  of  the  Montague  Lake  the  filling  was  nearly 
complete  and  the  lake  bottom  is  at  a  high  level,  and  the  deepest  portion  of 
it,  the  tlu-ead  of  the  old  stream,  has  been  removed  by  the  later  erosion  of  the 
river.  Beers  plain,  in  Northfield,  is  the  principal  area  of  the  old  lake  bot- 
tou\  (or  here,  rather,  river  bottom)  in  this  northern  portion.  It  is  separated 
by  the  great  delta  of  Millers  River  from  the  deep,  imfiUed  depression  in- 
which  lies  the  village  of  Montague.  The  latter  is  a  deep  hollow,  sur- 
rounded on  three  sides  by  rock,  while  on  the  north  the  great  scarp  of  the 
above  delta  foi'ms  its  boundary.  The  many  streams  which  join  and  run 
across  the  bottom  of  this  small  basin  have  obliterated  most  of  the  old  sur- 
face of  the  lake  bottom. 

There  is  a  certain  curious  parallelism  in  many  orographic  features 
between  this  basin  and  the  m^^ch  larger  Amherst  basin.  The  village  of 
Plainville,  in  this  latter  basin,  has  the  same  relative  position  as  Montagiie 
village.  To  the  west  of  each  rises  a  great  hill,  which  stood  as  an  island  in 
the  lake,  and  around  the  north  side  of  which  runs  a  stream  draining  the 
basin.  To  the  southeast  a  sharp  notch  between  the  Trias  and  the  crystal- 
line rocks  j)asses  into  the  next  basin  south.  To  the  south  the  Connecticiit 
cuts  through  the  Trias  in  a  narrow  gorge,  and  to  the  southwest,  in  each  case 
extends  the  broad  lateral  valley  once  occupied  by  the  flooded  river. 

THE  HADLEY  LAKE  BOTTOM. 

Here,  as  compared  with  the  preceding  basin,  the  conditions  are  wholly 
reversed,  and  the  space  occupied  by  the  high  terrace  is,  especially  along  the 
east  side  of  the  basin,  very  small  as  compared  with  that  covered  by  the  lake 
bottom.  The  real  disproportion  will  appear  more  clearly  if  one  imagines 
the  color  of  the  lake  bottom  (1  b  t)  on  the  map  extended  across  the  succes- 
sion of  shades  (t  1-4)  which  represent  the  later  erosion  terraces  cut  in  this 
lake  bottom  by  the  Connecticut  and  its  tributaries.  This  disproportion  is 
as  striking  in  a  vertical  as  in  a  horizontal  sense,  since  the  undulating  lake 
bottom  is  over  broad  areas  raised  only  a  few  feet  above  the  present  flood 
plain  of  the  Connecticut. 

MON  XXIX 43 


674       GEOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 

In  the  northern  part,  in  Greenfield,  the  lake  bottom  is  elevated  nearly 
to  the  level  of  the  shore  bench,  as  the  lake  was  here  shallow  from  the 
beginning,  and  narrow,  and  it  is  covered  mainly  by  quite  coarse  material. 
Farther  south,  in  the  south  of  this  town  and  in  the  north  of  Deerfield,  the 
original  depth  was  greater,  and  a  great  thickness  of  clays  gathered,  over 
which  the  flood  sands  were  swept,  as  detailed  in  the  section.     (See  p.  634.) 

South  of  the  delta  of  Deerfield  River,  through  the  southern  portion 
of  Deerfield  and  through  Hatfield,  the  lake  bottom  is  a  broad,  almost 
perfectly  horizontal  sand  plain;  chosen  for  the  base  line  of  the  Borden 
survey  as  the  most  perfect  plain  in  western  Massachusetts.  It  is  under- 
lain by  fine  white  sands,  with  delicate  cross  stratification  di^^ping  very 
commonly  about  15°  S.,  changing  downward  pretty  suddenly  into  fine, 
horizontal  clays.  This  plain  extends  from  the  foot  of  "The  Rocks"  across 
Hatfield  with  a  height  of  only  about  13  feet  above  the  highest  flood  plain 
of  the  Connecticut,  and  is  continuous  across  the  river  in  the  extensive 
plain  of  exactly  similar  character  and  elevation  which  extends  from  the 
south  of  Sunderland  down  through  North  Hadley  and  the  west  of  Amherst, 
and,  dividing  on  Mount  Warner,  sends  one  lobe  down  past  its  eastern  base, 
between  it  and  the  Amherst  ridge,  while  the  other  entirely  similar  lobe, 
which  formerly  skirted  its  western  base,  has  been  largely  removed  by  the 
oscillations  of  the  river  and  disguised  by  the  abundant  dunes  which  have 
formed  over  tlie  remaining  portion. 

One  can  not  well  cross  the  Amity  street  meadow,  west  of  Amherst,  and 
study  the  lower  slopes  of  Mount  Warner  and  its  southern  prolongation  with- 
out feeling  that  the  meadow  was  the  bottom  of  a  stream  whose  current 
molded  the  sides  of  Warner.  This  hill  stood  like  a  pier  in  the  midst  of 
the  broad  water,  but  nearer  its  western  side,  and  the  cm-rents  dividing  on 
it  wore  deepest  around  its  northern  base;  and  the  grooves  thus  formed 
extended  south,  widening  and  shallowing,  being  best  developed  at  Amity 
street — a  little  higher  and  less  marked  where  it  crosses  the  Northampton 
road,  but  traceable  like  a  distinct  river  bed  for  a  long  way  south  tlu-ough 
the  woods,  until  it  rises  and  blends  with  the  broad  plain  in  the  southwest 
part  of  Hadley,  after  the  obstructing  hill  had  been  passed. 

It  is  plain  that  the  western  branch  of  this  groove,  occupying  a  narrower 
passageway  and  directed  toward  the  Holyoke  notch,  was  the  deeper,  and 
so  determined  the  course  of  the  main  stream  on  the  recession  of  the  waters. 


THE  HADLEY  LAKE  BOTTOM.  675 

Because  the  eastern  branch  was  deepest  toward  the  north  and  rises  and 
widens  to  the  south,  it  has  given  rise  to  a  curious  little  drainage  area,  whose 
smaller  streams  head  in  its  southern  higher  portion  and  gather  and  run  north 
around  tlie  north  end  of  Mount  Warner. 

An  inspection  of  the  map  will  show  that  the  tail  of  the  high  terrace 
carried  out  from  Mount  Warner  is  curiously  directed  southeast,  another 
indication  of  the  greater  force  of  the  current  through  the  passage  to  the 
west  of  the  hill.  This  tail  is  carried  south  aci'oss  the  Northampton  road. 
Extending  across  this  road  and  much  farther  south  to  the  base  of  the  Holy- 
oke  range,  is  a  broad,  A^er}^  flat  plain,  underlain  by  clays  of  great  thickness, 
which  for  a  long  way  south  are  covered  by  only  a  thin  layer  of  sand,  so 
that  the  whole  rainfall  over  the  area  is  kept  very  near  the  surface,  and  the 
brooks  are  large  and  run  in  very  shallow  beds. 

The  groove  mentioned  above,  worn  by  the  waters  parting  on  Mount 
Warner,  seems  to  have  been  cut  into  the  clays  which  had  been  previously 
deposited  to  a  higher  level  than  the  bottom  of  the  groove  over  the  area 
where  the  latter  was  formed.  This  is  especially  clear  where  the  Northamp- 
ton road  crosses  the  groove  just  west  of  Amherst  and  rises  upon  the  plain 
south  of  Mount  Warner  just  mentioned.  It  goes  up  over  the  edges  of  the 
horizontal  clays  to  reach  this  plain.  Also,  on  the  west  side,  the  clays  rise 
at  the  south  line  of  Hatfield  72  feet  above  the  river  level.  This  falls  in  with 
many  other  indications  that  in  the  latter  portion  of  the  highest  water  stand 
the  eroding  and  carrying  activity  of  the  stream  was  considerably  increased. 
Another  similar  indication  is  that  over  the  lake  bottom  and  in  the  high 
terrace  everywhere,  and  under  every  variety  of  circumstances,  a  coarser 
stratum  overlies  finer  beds  as  the  last  deposit  of  the  flood  time,  as  if  the 
final  melting  of  the  ice  from  this  drainage  area  had  come  with  some 
suddenness. 

At  the  foot  of  Amity  street  another  interesting  observation  and  deduc- 
tion may  be  made.  Along  the  side  of  Mount  Warner  and  its  southern 
prolongation,  as  well  as  along  the  slope  of  the  Amherst  ridge  east  of  us, 
the  long  sand  bars  are  carried  south  just  as  they  were  left  by  the  flood, 
and  they  merge  below  with  the  broad,  flat  thread  of  the  channel,  it  also 
being  just  as  it  was  left  by  the  same  current  (barring,  of  course,  the  small 
erosion  of  the  brooks) ;  and  down  both  the  slopes  there  is  no  intermediate 
terrace  or  line  of  erosion  to  indicate  any  intermediate  water  stand  between 


676  GEOLOGY  OP  OLD  HAMPSHIRE  COUNTY,  MASS. 

the  high-water  stand  of  the  flood  time  and  the  present  flood  plain  of  the 
river;  and  this  observation  may  be  made  over  all  the  area  I  have  been 
describing  in  this  section  south  of  the  old  waterfall  at  the  Lily  Pond  in  Gill. 
(See  PI.  XXII,  p.  725.)  This  indicates  a  very  sudden  shrinkage  of  the 
waters  from  their  maximum  to  nearly  their  present  volume. 

I  have  had  occasion  already  to  speak  of  the  depression  south  of  Col- 
lege Hill,  among  the  drumlins,  and  of  the  more  extended  and  much  deeper 
depressions  west  of  South  Amherst,  and  to  some  extent,  also,  of  the  still 
larger  depression  of  the  East  Street  basin.     (See  p.  641.) 

The  best  point  from  which  to  study  this  basin  is  at  the  highest  part  of 
the  road  going  north  from  East  Street  village.  One  looks  across  to  the 
massive  terrace  which  flanlvs  the  Pelham  Hills  and  sees  at  his  feet  the  heavy 
sand  bars  which  had  been  carried  south  at  the  base  of  the  hill  on  which 
he  stands  before  the  current  was  cut  ofiP  by  the  delta  of  Cushmans  Brook, 
which  stretches  in  plain  sight  across  the  north  end  of  the  basin.  The  face 
of  the  high  terrace  opposite  is  cut  by  a  series  of  finely  preserved  terraces, 
which  seem  to  have  been  formed  while  the  East  Street  Lake  was  being 
slowly  drained  by  the  gradual  lowering  of  its  outlet,  Fort  Eiver,  in  its 
course  tlu'ough  the  tangle  of  drumlins  south  of  College  Hill  by  which  it 
reaches  the  main  valley.  These  terraces  are  figured  by  President  Hitch- 
cock.-^ The  sands  were  carried  out  in  force  over  the  lake  bottom  nearly  as 
far  south  as  the  village,  and  from  this  point  south  the  lake  bottom  is  made 
up  of  clay,  with  often  less  than  3  feet  of  fine  sand  covering  it,  and  this 
forms  the  lake  bottom  south  across  the  low  extensive  Lawrence  Swamp, 
which  is,  as  it  were,  the  remnant  of  the  old  lake  imperfectly  drained  by  the 
single  outlet  of  the  basin,  Fort  River. 

In  its  southern  portion  the  abundant  sands  around  Dwight's  station  and 
along  the  northern  flank  of  Mount  Holyoke  have  been  carried  down  and 
spread  out  over  the  clays  by  undertow,  and  slope  gradually  from  the  high- 
water  line  out  into  the  basin,  and  this  is  the  case  along  the  whole  north 
flank  of  Holyoke. 

Beyond  the  great  oxbow  region  of  the  Northampton  Meadows,  the  lake 
bottom  across  Southampton,  Westfield,  and  Southwick,  except  where  it  has 
been  removed  by  the  basin  of  Westfield  River,  is  well  preserved,  and  is  in 
effect  the  deep-water  channel,  or  channels,  of  the  broad  arm  of  the  flood 


'  Surface  Geology,  PI.  IX,  fig.  2. 


THE  OAMP-MEETING  CUTTING.  677 

stream  which  occupiod  this  lobe  of  the  valley,  and  which  left  lake  bottom 
and  border  alike  intact  on  the  recession  of  the  waters.  Over  this  region  it 
seemed  more  convenient  to  discuss  them  together,  as  has  been  done  above. 
(See  p.  650.) 

THE   SPRINGFIELD   LAKE   BOTTOM. 

On  the  east  side  of  the  river,  at  Smiths  Ferry,  south  of  the  great  Dry 
Hill  bar,  and  again  much  farther  south,  across  West  Springfield  and  Agawam, 
are  limited  areas  occupying  a  level  considerably  below  that  of  the  high 
terrace  or  filled  portion  of  the  lake,  connected  with  it  by  a  plainly  marked 
scarp  of  deposition,  and  on  the  other  side  separated  from  the  later  terraces 
by  an  equally  well-marked  scarp  of  erosion.  To  these  I  have  assigned  on 
the  map  the  same  color  as  that  given  to  the  lake  bottom  in  the  northern 
lakes.  They  are,  however,  of  so  limited  extent  that  the  lake  may  be  fairly 
contrasted  with  the  more  northern  ones  as  a  fiUed-up  lake,  in  so  far  as  its 
northern  half  in  Massachusetts  is  concerned. 

DETAILED  SECTIONS  OF  THE  TERRACES  AND  LAKE  BOTTOMS,  SHOWING 
SEVERAL  ADVANCES  OF  THE  ICE  FRONT. 

THE   CAMP-MEETINGr   CUTTING. 

The  cutting  of  the  Canal  Railroad,  made  in  December,  1880,  through 
the  plain  on  the  north  line  of  Northampton,  at  the  northern  edge  of  which 
the  Methodist  camp-meeting  grounds,  called  Laurel  Park,  are  situated,^  was 
at  once  the  most  complicated  and,  for  the  information  it  gave  concerning  the 
oscillations  of  the  ice,  the  most  instructive  of  all  those  opened  in  the  valley 
of  late  years.  It  extended,  with  an  average  depth  of  20  feet,  for  3,250  feet. 
I  studied  it  with  great  care  during  the  progress  of  the  work  and  took  many 
sketches  of  all  parts  of  it.  I  found  the  winter  time  in  one  respect  very  favor- 
able for  the  study  of  these  walls  of  incoherent  sands  and  clays,  as  in  the 
steady  cold  they  remained  vertical  for  a  long  time  and  "weathered"  like 
banks  of  sandstone  and  shale,  bringing  out  many  refinements  of  texture 
which  would  otherwise  have  been  overlooked.  It  was  like  an  anatomist's 
"frozen  section."  The  cutting  afforded  two  sections  50  feet  apart,  and  after 
its  completion  the  steam  shovel  was  put  into  the  bank  both  to  the  right  and 

1  This  cutting  is  j  ust  west  of  the  apex  of  the  great  Hadley  bend  of  the  Connecticut,  where  the  first 
road  crosses  the  railroad. 


678  GEOLOGY  OP  OLD  HAMPSHIEE  COUNTY,  MASS. 

to  the  left,  and  worked  back  north  from  the  brook  to  be  mentioned  to  the 
oldest  till,  giving  two  more  sections,  2  rods  farther  from  the  center  on  either 
side,  and  in  the  most  difficult  part  of  the  line.  (See  PL  XV,  and  PI.  XVIII, 
figs.  2,  3,  at  p.  694.) 

POSITION  AUD   CONTOUR   OF   THE  TERRACE. 

Coming  down  from  Deei-field,  the  great  plain  of  the  Borden  base  line 
(Ibt)  sinks  across  Whately  and  Hatfield  from  220  feet  to  170  feet  and 
abuts  upon  "The  Rocks,"  a  low,  jagged  reef  of  exposed  ledges,  back  of 
and  above  which  the  lake  bench  flanks  the  higher  hills  to  the  west.  At  the 
north  line  of  Northampton  this  plain  (1  b  t)  rises  by  a  gradual  slope  to  the 
height  of  203  feet,  and  still  flanks  the  southern  prolongation  of  the  ridge  for 
nearly  a  mile  south  and  merges  around  the  south  end  of  Elizabeth  Rock 
with  the  delta  sands  (1  s  h)  which  fill  the  great  Northampton  Bay  and  rise 
oTadu.ally  to  295  feet  in  Florence.  Resting  thiTs  on  the  west  against  the 
rocks,  the  plain  on  the  east  overhangs  the  westernmost  portion  of  the  great 
Hadley  bend  of  the  Connecticut,  which  has  here  eaten  into  and  destroyed  a 
large  portion  of  it.  At  its  southern  end,  also,  brooks  have  cut  down  into 
the  clays  and  obscured  its  connection  with  the  delta  sand  farther  south. 
In  all  directions  between  north,  east,  and  south  the  valley  is  open  and 
many  miles  wide.  Mount  Toby  rises  in  the  plain  3  J  miles  to  the  northeast, 
and  it  is  a  point  whence  one  gets  a  rare  view  of  the  beautiful  valley.  The 
plain  lay  thus  in  the  open  waters  of  the  Hadley  Lake,  and  it  was  formed 
more  than  100  feet  below  the  surface  of  the  lake  waters. 

From  the  clay  pit  at  the  southeastern  corner  of  the  plain  one  goes  down 
the  steep  slope  70  feet  to  the  river,  at  the  extreme  western  point  of  the  great 
bend  over  an  unbroken  succession  of  laminated  clays,  which  rise  to  within 
6  feet  of  the  surface,  being  capped  by  sand,  and  as  I  could  trace  them  some 
way  north  in  the  old  cutting  of  the  Connecticut  River  Railroad,  to  which 
the  new  cutting  runs  nearly  parallel,  and  found  traces  of  the  same  clays  at 
the  north  end,  I  assumed  the  upward  succession  here  to  be  rock,  till,  heavy 
clays,  and  sand,  and  that  this  gave  the  greatest  height  of  the  clays  for  this 
portion  of  the  valley,  and  I  had  no  conception  of  the  exceedingly  complex 
anatomy  of  what  seemed  a  very  simple  and  normal  section. 


^  XXIX.  PL.  XV. 


)L0  BROOK  BED. 


30VE  SEA  LEVEL. 


30VE  SEA  LEVEL. 


L  THIN 
OOVi^N 


,BOVE  SEA  LEVEL. 


U.  S.  GEOLOGICAL  SURVEY. 


MONOGRAPH  XXIX.  PL.  XV. 


UPPER     SAN  DS 


TRANSVERSE   SECTION   OF   OLD   BROOK   BED 


125  FEET  ABOVE  SEA  LEVEL 


THIS  BED  IS  A  COMPLETE  TILL  ABOVE    E   FORMED  OF    BOWLDERS,   ETC. 
ABRADED    FROM    THE    DRUMLIN,  KNEADED    WITH    THE  CLAY    AND    SAND 

LAYER,  BELOW   IT   PASSES  GRADUALLY   INTO  A   CONTORTE:0_  CLAY_ 


^L^ItHIE^WORN   SURFACE, 


UPPER    Sanqs 


SECOND   ICE- 
WORN   SURFACE 


ANYTHING   ELSE    IN   THE   VALLEY 


I  SECOND   ICE-WORN 
SURFACE 


125   FEET   ABOVE   SEA  LEVEL. 


M 


SECTION  AT  THE   CAMP  MEETING    CUTTING  ON  THE  NORTH   LINE  OF    NORTHAMPTON,    SHOWING  THREE  READVANCES  OF  THE  GLACIAL  ICE. 


HORIZONTAL   AND  VERTICAL  SCAl.E 


THE  CAMP-MEETING  CUTTING.  679 

DESCRIPTION   DP   THE    SECTION. 

Tlie  cutting  enters  the  hill  at  the  north  end,  near  the  stntion  of  the 
canip-nieeting-  grounds,  and  deepens  to  18  feet  in  the  first  (j^uarter,  at  the 
overhead  bridge  of  the  road  to  Hatfield.  It  soon  rises  to  24  feet  and  con- 
tinues with  this  depth  to  the  end.  Exactly  in  the  middle  it  is  cut  in  two 
b}'  the  narrow  sand  gulch  of  a  brook  which  runs  east  to  the  Connecticut. 

The  drumlin. — (PL  XV,  C  F.)  The  central  and  the  oldest  member 
of  the  series  exposed  here  is  a  di-umlin  of  the  "lower  till" — indeed,  the 
lowest  till— which  rises  with  easy  slope  just  south  of  the  overhead  bridge 
to  a  height  of  18  feet,  and  continues  about  300  feet  before  it  dips,  with  the 
same  easy  slope,  below  the  level  of  the  railroad.  Excluding  for  the  moment 
an  upper  layer  of  2  to  3^  feet,  the  whole  mass  is  a  stony  clay  of  extreme 
compactness,  in  which  the  steam  shovel  could  make  but  little  progress,  and 
which,  six  months  after  the  work  was  done,  still  retained  the  marks  of  the 
shovel  teeth.  Most  of  the  pebbles  were  about  or  under  6  inches  in  diameter, 
of  well-marked  glacial  forms,  and  often  scratched,  mostly  of  black  argillite 
and  mica-schist,  which  borders  the  valley  from  the  middle  of  Whately 
north.  The  mass,  when  freshly  cut,  was  of  a  dark-gray  color,  nearly 
black,  but  with  a  faint  shade  of  brown  and  green.  It  showed  no  trace  of 
stratification  at  first,  but  after  months  of  weathering  a  rude  horizontal 
bedding  made  its  appearance.  Lines  from  3  to  6  inches  apart  could  in 
places  be  traced  for  a  distance  across  the  mass,  and  the  pebbles  lay  parallel 
to  these  planes  more  often  than  in  other  directions. 

In  the  upper  2  or  3  feet  of  this  mass,  excepted  above  from  the 
foregoing  description,  occurred  a  great  number  of  bowlders,  up  to  4  or  5  feet 
on  a  side,  almost  entirely  of  the  tonalite  which  skirts  the  valley  from  the 
middle  of  Whately  south  past  the  section.  This  upper  portion  is  not  sepa- 
rated by  any  line  of  demarcation  from  the  portion  below.  Nor  does  the 
stony  clay  in  which  these  large  bowlders  are  embedded  present  any  dif- 
ference in  texture  or  color,  whether  one  examines  a  fresh  or  a  weathered 
surface,  when  it  is  wet,  dry,  or  frozen.  This  seems  to  me  to  represent  the 
portion  of  the  ground  moraine  which  was  brought  into  its  present  position 
toward  the  close  of  the  activity  of  the  main  ice,  when  the  ice  which  passed 
over  this  spot  was  deflected  into  the  valley  from  the  west  over  the  ledges  of 


680  GEOLOGY  OF  OLD  HAMPSHIKE  COUNTY,  MASS. 

tonalite,  instead  of,  as  earlier,  over  the  slate  area  farther  north.  The  origi- 
nal surface  of  this  drumlin  represents  the  oldest  surface  over  which  the  ice 
moved. 

The  bowlder  bed. — (PI.  XV,  D  F.)  The  drumlin  slopes  easily  south- 
ward below  the  level  of  the  cutting ;  and  resting  against  this  slope, 
though  not  rising  quite  to  the  level  of  the  top  of  the  drumlin,  is  a  mass  of 
bowlders,  from  6  inches  to  2  feet  in  size,  with  very  little  admixture  of  finer 
material,  the  bowlders  largely  tonalite,  like  those  in  the  upper  portion  of 
the  drumlin,  quite  well  rounded  and  showing  no  traces  of  scratching.  This 
slopes  off  very  gradually  at  top  and  descends  below  the  level  of  exposure 
at  a  distance  of  120  feet  from  the  till.  That  this  bowlder  bed  was  concen- 
trated by  water  action  from  the  bowlder-crowded  upper  layer  of  the  till 
below  it  seems  to  me  probable.  Whether  this  was  done  in  a  violent  current 
beneath  the  ice,  or  whether  it  is  the  oldest  shore  deposit  of  the  lake  which 
occupied  the  Hadley  basin  on  the  recession  of  the  ice,  can  not  be  made 
quite  clear,  though  I  incline  strongly  to  the  latter  view,  which  will,  I  think, 
be  seen  in  the  sequel  to  be  best  supported  by  all  the  facts.  It  is  also  pos- 
sible that  it  is  a  terminal  moraine  of  the  retreating  ice,  and  its  surface  may 
represent  the  second  surface  over  which  the  ice  moved. 

Tlie  pinh  beach  sands. — (PL  XV,  H  and  L  M.)  Resting  upon  this 
bowlder  bed,  and  separating  it  from  a  second  till  above,  is  a  thin  layer 
of  well-washed  pink  sand,  disconnected  and  only  a  few  inches  thick  on 
the  east  wall  of  the  cutting,  but  nearly  2  feet  thick  on  the  west  wall,  which 
is  plainly  the  remnant  of  a  much  thicker  deposit  that  has  been  planed  away 
by  ice  which  deposited  the  till  above  it.  This  sand  layer  disappears  here 
below  the  level,  but  if  we  follow  the  heavy  sands  which  cover  the  second 
till  soiTthward  we  find  them  resting  in  marked  unconformity  upon  the  same 
pink  sand,  which  is  easily  identified  with  the  thin  layer  already  described 
by  its  color,  size  of  grains,  and  well-worn  and  sorted  state,  and  distinguished 
from  the  upper  sands  by  the  absence  of  the  clay  partings  which  characterize 
the  latter.  Here  the  pink  sands  rise  in  the  midst  of  the  newer  sands  on  the 
east  side  to  the  height  of  14  feet,  in  a  dome  with  easy  slope  northward  and 
more  rapid  southward,  while  in  the  west  wall  they  appear  in  much  greater 
force,  the  distance  from  the  point  where  they  first  rise  above  the  level  of 
the  road  to  where  they  sink  again  below  it  being  250  feet.  The  gradual 
southward  rise  of  the  surface  of  the  sands  soon  brings  them  to  the  top  of  the 


THE  CAMP-MEETING  CUTTING.  681 

cutting,  ;iu(l  they  make  its  whole  thickness,  Ijeiug,  indeed,  somewhat  eroded 
above  for  over  50  feet,  and  then  sink  and  rise  again  in  a  smaller  mound 
before  th("\-  limilh-  disappear.  The  bottom  of  the  sand  was  nowhere 
exposed.  These  sands  dip  southward  15°  on  the  east  side  and  are  nearly 
horizontal  on  the  west;  they  are  marked  by  delicate  cross-bedding,  and  here 
and  there  layers  of  pebbles  up  to  an  inch  in  size  occur.  When  first  uncov- 
ered they  were  of  a  delicate  pink  color,  so  that  I  was  in  the  habit  of  calling 
them  peachblow  sands.  They  differ  from  every  other  sand  in  the  valley 
in  being  perfect  beach  sands.  The  sand  is  more  completely  sorted  and 
rounded,  and  the  pebbles  show  the  synunetrically  rounded  forms  and  satiny 
surface  of  beach  pebbles.  These  pebbles  are  often  cemented  by  calcite, 
a  thing  never  seen,  in  the  Champlain  gravels. 

The  whole  is  now  broken  up  by  a  multitude  of  faults  and  slips  and  in 
places  tlirown  into  sharp  zigzags  like 

a  flio-ht  of  stairs.     It  is  not,  however,  .^i'^5:P>C~~:''-'^;S^:55>. 

molded  into  the  complex  curves  seen       ^^tr^^-^^^i^-:  ■'"^.^^^C-^ 

m  the  more  clayey  sands  above,  which      ^^^^^0p^^^£&>^^'^3^^^^ 
we  shall  see  to  have  been  mdepend-    ^^^^^^:yzK:-':pl^:^::ip^:^i-':-^^ 
ently  and  at  a  later  time  subjected  to  a         *^^^^^fe^^-SSS^i^^^^^B 
similar  crushing.     The  surface  of  the  ^^^.vii-i.^ -■  - ~ 

Sands    rises     with    an    easy     even     slope    F-a-^.-Block  of  frozen  ■•  pink  sand/'  showing  Ane  sy^^ 

J  1  tern  of  joints.    The  lionzontal  linea  are  the  bedding  of 

and  sinks  with   the    same    smooth  lines       tl^esand.    The  vertical  are  strongly  marked  joint  planes. 

The  block  was  15  inches  square. 

below  one's  sight.  A  cm'ious  appear- 
ance shown  (fig.  45)  by  a  frozen  block  of  the  sand  may  even  be  due  to  the 
development  by  the  weight  of  the  ice  mass,  or  by  torsion  in  connection  with 
its  thi'ust,  of  a  latent  pressure  cleavage.  A  frozen  block  from  the  north  end 
of  the  east  opening  of  the  sands  had  carved  out  upon  it  by  the  wind  a  series 
of  perfectly  parallel  cracks,  3  to  4"™  apart  and  about  at  right  angles  to  the 
bedding,  and  these,  together  with  the  bedding,  had  been  very  beautifully 
dissected  out  by  the  wind. 

The  sands  here  dip  southward,  and  the  ice  coming  from  the  north  had 
ridden  over  the  upturned  edges  of  the  laminse,  so  that  the  plane  of  these 
fissures  was  at  right  angles  to  the  direction  of  the  thrust  of  the  ice.  I  have 
little  doubt  that  the  ice  moved  over  this  sand  bed  while  it  was  frozen,  and 
that  this  is  the  reason  why  the  sands  are  so  often  and  so  sharply  faulted  and 
broken  and  not  thrown  into  twisted,  contorted  folds,-  as  happened  later  to 


682  GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

the  upper  sands  when  the  ice  was  plainly  thrust  out  into  the  waters  of  the 
lake — ^then  risen  higher — and  plowed  up  its  bottom. 

While  I  was  studying  the  sands  the  workmen  were  breaking  off  masses 
of  the  frozen  sand  with  wedges  and  heavy  hammers  to  make  way  for  the 
steam  shovel,  and  the  rock  thus  formed  was  one  of  great  hardness.  The 
depression  which  separates  the  two  parts  of  the  sand  on  the  west  side  is 
lined  by  a  thick  layer  of  unstratified  pebbles  concentrated  from  the  pink 
sands,  and  seems  to  me  a  "pot-hole"  in  the  sand,  caused  by  the  waters  of 
a  moulin  of  the  glacier,  though  it  may  be  an  old  brook  bed.  The  eroded 
surface  of  these  sands  is  the  third  erosion  plane  occupied  by  the  ice. 

The  second  tiU.~(V\.  XV,  E  to  T.)  Returning  now  to  the  south  end 
of  the  great  drumlin,  we  iiud  the  second  till,  which  rests  upon  the  pink 
sands,  to  have  a  thickness  of  2  to  3  feet,  and  to  be  sharply  demarcated 
on  the  east  from  the  pink  sand  and  the  bowlder  bed  below,  the  boundary 
being  a  straight  line,  and  separated  above  from  a  third  layer  of  till  by  the 
thin,  disconnected  remnants  of  a  second  sand,  which  thickens  rapidly 
southward,  so  that  where  the  second  till  goes  out  of  sight  below,  it  is 
separated  from  the  third  till  above  by  15  feet  of  sand.  This  second  till 
is  the  hardest  stony  clay,  wholly  indistinguishable  from  the  oldest  till  of 
the  drumlin,  against  which  it  seems  to  rest  in  a  wedge-shaped  end,  although 
no  distinct  line  of  demarcation  can  be  seen  between  them.  The  ice  seems 
still  to  have  rested  upon  the  surface  of  the  older  till,  or  to  have  eroded 
down  to  it,  and  a  train  of  large  bowlders  appears  in  the  second  till  a  little 
way  from  the  great  till,  quite  plainly  derived  from  it,  as  farther  on  they 
are  wanting  in  the  second  till.  Farther  south,  where  the  ice  rode  up  over 
the  pink  beach  sands  as  already  described,  there  is  but  slight  trace  of  till— 
a  few  large  bowlders  resting  on  the  sands — that  which  we  have  followed 
from  the  oldest  till  seeming  to  have  been  deiived  from  the  erosion  of  the 
drumlin;  and  here  the  material  has  failed  or  been  removed  at  a  later  time 
by  water,  as  has  much  of  the  pink  sand,  which  one  can  follow  by  its  color 
as  it  is  swept  southward  and  now  lies  between  the  layers  of  clay  of  later 
deposition,  showing  that  ice  and  water  worked  together  here. 

The  second  sands. — (PI.  XV,  H  to  L.)  At  the  sovith  slope  of  the 
di'umlin  the  sands  which  cover  the  second  till  and  separate  it  from  the 
third  appear  only  as  a  thin,  disconnected  film,  rising  to  a  thickness  of  8  to 
10  inches  on  the  east  side,  while  on  the  west  they  are  continuous  and 


THE  CAMP-MEETING  CUTTING.  683 

nearly  2  feet  tliick  iind  rise  up  uutu  the  back  of  the  flrumlin  northwardly, 
where  thev  are  sheared  off  abruptly  by  the  tlnrd  till,  which  here  blends 
with  the  second. 

Southward,  the  third  till,  which  passes  down  the  south  slope  of  the 
druinlin,  sinkini^-  deei)ly  into  these  sands,  rises  with  an  easy  gradient  up  to 
the  surface  of  tlie  sands  on  the  east  side  of  the  cutting,  its  further  extent 
being  now  cut  otf  by  erosion;  and  on  the  west  side  rising  in  the  same  way  to 
within  a  foot  of  the  surface  and  then  extending  50  feet  over  the  sands,  and 
fiinall)^  thickening  downward  to  6  feet  and  ending  abruptly  in  the  sands  in  a 
club-shaped  mass,  the  sands  that  rest  against  its  south  face  being  continu- 
ous with  those  beneath  it  and  like  thein  in  every  way.  From  this  point 
the  sands  make  the  whole  thickness  of  the  wall,  24  feet,  for  a  distance  of 
224  feet  to  the  ravine,  and  crossing  this  (25  feet  wide),  the  sands,  with  the 
bottom  nowhere  exposed,  run  under  a  bed  of  clay,  the  same  as  that  north 
of  the  drumlin,  and  go  on  with  a  slight  dip  southward  and  fold  over  the 
pinlc  sands  already  described.  They  are  here  much  thinned,  and  dip 
beneath  the  surface  near  the  south  end  of  the  cutting.  These  are,  for 
the  most  part,  coarse  to  very  coarse,  reddish  sands,  laid  down  by  a  strong 
and  steady  southward  current  in  layers  which  are  horizontal  for  long  dis- 
tances or  slightly  inclined  southward.  Only  for  a  few  rods  on  the  west 
side  and  just  south  of  where  the  third  till  rises  upon  them  are  they  clean, 
white,  better-sorted  sands,  the  cross-bedding  dipping  sharply  north  for  a 
time  and  then  as  sharply  south,^  and  their  eroded  surfaces  are  covered  by 
a  h^yer  of  well-worn  beach  |)ebbles.  The  bedding  is  everywhere,  except 
in  the  white  sands,  sharjjly  marked  by  thin  layers  of  very  fine  sand  2  to  6 
inches  apai't,  which  are  persistent  for  long  distances,  and  which  farther  south, 
where  the  sands  have  run  beneath  the  clay,  become  layers  of  true  clay, 
and  toward  the  top  of  the  sands  approach  nearer  by  the  thinning  out  of  the 
intervening  sand  layers,  and  so  effect  a  transition  into  the  clays. 

For  a  long  distance  south  of  the  brook  this  arrangement  is  well  devel- 
oped. Layers  of  sand,  beautifully  rippled  at  surface  and  about  6  inches 
thick,  are  capped  by  layers  of  clay,  one-fourth  of  an  inch  thick,  which 
takes  an  accurate  cast  of  the  ripples  below  and  makes  the  upper  surface 
more  or  less  nearly  horizontal. 

1  These  are  back-set  and  front-set  sands,  in  the  terminology  of  Professor  Davis.  Bull.  Geol.  Soo. 
America,  1890  p.  195. 


684  GEOLOGY  OF  OLD  HAMPSHIRE  COU:S[TY,  MASS. 

lu  the  frozen  wall  the  sand  layers  were  deeply  worked  out  by  the 
wmd,  and  the  clay  layers  projected  one  above  another  like  the  eaves  of  a 
fluted  iron  roof  By  the  thinning  of  the  sand  layers  the  whole  deposit 
loses  in  thickness  and  the  superincumbent  clay  sinks  lower.  This  plainly 
indicates  a  strong  current  in  the  summer  floods,  a  quiet  one  during  the 
winter,  and  a  depth  of  water  sufficient  to  so  far  remove  the  banks  of  the 
stream  to  the  west  that  the  floods  brought  only  thin  layers  of  sand  out  over 
the  clay  to  this  point,  layers  which  have  mostly  dwindled  to  nothing  before 
we  reach  the  south  end  of  the  cutting. 

The  sands,  as  indicated  above,  run  up  on  the  south  slope  of  the  drumlin 
in  a  thin  film,  and  could  in  one  section  be  traced  almost  or  quite  continu- 
oiTsly  across  it,  to  join  a  thick  bed  of  similar  sand,  whicli  extends  to  the 
north  end  of  the  section,  where  it  is  cut  off  by  erosion.  It  is  capped,  as  in 
the  layer  south  of  the  di-umlin,  by  the  same  thick  deposit  of  clay.  These 
sands  are  finer  than  those  already  described,  especially  near  the  drumlin, 
manifestly  because  they  were  laid  down  in  the  sheltered  area  behind  it. 
Northward  they  grow  coarser,  and  at  the  extreme  north  are  gravelly,  and 
iron-shot  where  the  water  circulated  below  the  clays,  with  coarse  cross- 
bedding  dipping  south.  Through  most  of  the  distance  the  beds  are 
(or  were)  horizontal,  and  show  repeated  oscillations  of  coarser  and  finer 
layers,  and  everywhere  most  delicate  cross-bedding.  Upward,  the  whole 
gradually  becomes  finer,  clay  layers  -making  their  appearance,  which  at  the 
end  effect  a  somewhat  sudden  transition  into  the  clay  above;  in  short,  the 
sands  agree  in  all  points  with  the  corresponding  sands  south  of  the  drumlin. 

The  third  till. — It  will  make  clearer  the  complex  series  we  are  studying 
if  I  call  attention  to  the  four  surfaces  on  which  the  ice  has  rested.  The  first 
is  the  surface  of  the  drumlin.  The  second  is  the  surface  of  the  second  till, 
which  has  eroded  the  pink  sands ;  and  as  the  till  layer  seems  largely  derived 
from  the  broad  surface  of  the  di-umlin,  this  layer  lessens  and  the  ice  rests 
almost  directly  on  the  sands  in  the  continuation  of  the  surface  southward. 
Consideration  of  the  third  till,  which  is  the  subject  of  discussion  here,  may 
be  omitted  for  a  moment.  The  fourth  and  last  surface  occupied  by  the  ice  is 
very  clearly  defined  along  the  whole  length  of  the  section.  It  is  the  hori- 
zontal upper  surface  of  the  clays  above  the  second  sands  from  the  north  end 
of  the  section  to  the  drumlin,  and  is  continued  along  the  eroded  surface  of 
the  drumlin,  and  is  the  surface  of  the  fourth  till  from  the  beginning  of  the 


THE  CAMP-MEETING  CUTTING.  685 

same  at  the  south  end  of  the  (h-iiiuHu  or  southward.  This  fourth  till  is  made 
up  of  material  derived  from  the  drumliu  and  uiolded  with  the  clay  and  sand 
below,  and  so  "-rades  southwardly  into  the  contorted  clays  uncontaminated 
with  o-lacial  debris,  whose  planed-off  upper  surface  is  the  continuation  of 
the  fourth  surface  occupied  by  the  ice  in  the  whole  distance  south  of  the 
centi-al  o-oro-e  to  the  place  Avhere  this  ice-worn  surface  sinks  below  the  level 
of  the  section. 

Because  of  this  blending  of  the  clays  with  the  second  sands  beneath 
them  by  the  fourth  ice,  the  relative  importance  of  the  third  surface  occupied 
by  the  ice  in  the  midst  of  the  second  sands  can  not  be  clearly  made  out. 
It  is  seen  in  the  sloping  layer  of  till  that  extends  down  through  the  second 
sands,  ending  at  the  north  edge  of  the  brook  gorge,  and  is  marked  "third 
ice-worn  surface"  on  the  main  section.  Some  part  of  the  deep  erosion  of 
the  second  sands  between  this  point  and  the  south  end  of  the  drumlin  seems 
due  to  this  third  ice  advance. 

In  the  opposite  side  of  the  cutting,  50  feet  west  of  and  parallel  with  the 
above,  the  third  layer  of  till  ends  abruptly  in  the  sands,  soon  after  thicken- 
ing to  7  feet  and  rising  nearly  to  the  surface  in  a  way  peculiar  and  difficult 
to  explain.  It  is  here  a  compact,  stony  clay,  in  which,  near  the  end,  I 
coimted  twenty  bowlders  12  to  16  inches  long,  all  of  glacial  shapes  and 
many  striated.  As  seen  in  the  wall  of  the  cutting,  it  ends  in  three  long, 
sharp  teeth  projected  southward,  receiving  between  themselves  correspond- 
ing projections  of  the  sands;  and  these  projections  are  made  up  of  laminae, 
which  begin  against  the  till  and  extend  from  it  with  j)erfect  regularity, 
exactly  as  if  it  were  the  fluited  face  of  a  sea  cliff  and  the  sands  had  been 
laid  down  against  it.  There  seems  to  be  no  question  here  of  a  thrusting  of 
the  ice  into  the  sands  after  their  accumiilation,  but  it  would  seem  that  the 
third  till  represents  a  second  advance  of  the  ice  after  a  slight  retrogression, 
and  that  here  it  piished  itself  over  the  sands  of  the  lake  or  estuary  as  before, 
with  the  difference  that  now  the  water  stand  was  higher  and  the  snout  of 
the  glacier  was  thi-ust  out  into  the  lake,  gouging  and  crumpling  the  beds  at 
its  bottom.  It  ended  here  for  a  time  and  then  retreated,  leaving  the  till, 
which  it  had  gathered  mainly  from  the  drumlin,  covering  the  sands  to  this 
point.  The  deposition  of  the  sand  continued  uninterruptedly  except  so  far 
as  the  space  was  occupied  by  the  ice,  and  the  sand  increased  arotmd  and 
over  the  till  as  soon  as  the  ice  disappeared. 


686  GEOLOGY  OF  OLD  HAMPSHIEB  COUNTY,  MASS. 

Turnins'  to  the  second  cut  on  tlie  east  side,  which  was  50  feet  farther 
out  in  the  lake  and  parallel  to  the  two  last  described,  we  find  the  till  homoge- 
neous in  the  lower  2  feet  of  its  thickness.  Then  it  runs  up  over  the  sands 
and  thins  to  a  foot  in  thickness,  and  is  then  prolonged  in  a  stratified  bed  of 
the  same  dark  greenish-black  sandy  clay,  Avhich  ends  abruptly  (thickening 
slightly  before  its  ending)  in  a  sharp  point,  the  last  portion  being  beauti- 
fully cross-bedded  and  apparently  the  product  of  a  single  plunging  wave 
from  beneath  the  ice.  This  is  inclosed  above  and  below  in  the  light-yel- 
low coarse  sands,  which  beneath  are  undisturbed  so  far  back  as  traces  of 
lamination  occur  in  the  stony  clay  above,  and  are  conspicuously  con- 
torted farther  back  beneath  the  amorphous  and  ice-carried  portion  of  the 

same  bed. 

At  the  fourth  cutting  parallel  to  those  last  discussed  (the  most  west- 
erly), where  the  till  runs  up  on  the  sand,  it  splits  into  three  or  four  layers, 
each  successive  one  running  up  with  sharper  angle  and  being  separated  by 
thickening  sheets  of  flood  sands;  and  the  till  reaches  here  its  greatest  height. 
Some  layers  of  the  till  bend  irregularly  and  sink  deeper  into  the  sands 
and  extend  farther  south,  but  are  cut  off  by  the  brook  erosion  before  the 
connection  southward  is  made.     (PI.  XVIII,  fig.  2,  p.  694.) 

The  transition  of  the  sands  to  clays  beneath  this  till  indicates  a  deep- 
ening of  the  waters  southwardly,  by  which  the  ice  was  more  or  less  buoyed 
up  allowing  a  portion  of  the  sands  described  above  to  accumulate  beneath 
it  after  which  the  ice  dropped  again  upon  the  sands.  This  was  repeated 
several  times,  and  at  one  of  these  times  a  mass  of  water  from  beneath  the  ice 
swept  into  the  sands  the  curious  point  of  remanie  di'ift  described  above,  and 
finally  the  ice  was  floated  away  to  the  south  as  icebergs,  allowing  the  sands 
to  continue  their  accumulation  over  the  till  it  had  left. 

The  clays  above  the  second  sands. — These  are,  from  one  end  of  the 
cuttino-  to  the  other,  the  common  Champlain  clays  of  the  valley,  formed 
from  the  wash  of  till,  and  where  not  disturbed  are  thin-laminated  in  layers 
8  to  12™™  thick,  each  layer  buff  colored  and  sand}^  in  the  upper  third,  and 
composed  of  fine  fat  clay  in  the  lower  two-thirds. 

The  fourth  till  and  its  effects  upon  the  clays  and  sands  leloiv. — Starting 
from  the  north  end  of  the  opening,  the  surface  of  the  clays  is  an  almost 
perfectly  level  surface  of  erosion  on  to  the  drumlin.  The  ice  has  passed 
over  it,  planing  it  down  to  this  level,  twisting  and  contorting  it  and  the 


THE  CAMr-MEETING  CUTTING.  687 

sands  Ix'iR'atli  it  into  tlio  greatest  confnsion,  kneailing  tlieni  tog-ether,  press- 
in"-  tlic  clav  in  yrcat  bosses  down  into  tlic  sands,  in  some  places  destroying 
the  lamination  of  the  claN'  entirely;  in  others,  where  the  alternation  of 
line  sand  and  fat  clay  was  more  clearly  marked,  ])roducing-  in  each  layer 
masses  where  a  smoothed  snrface  resembled  marbled  paper.  This  contor- 
tion increased  to  its  maximum  where  the  two  beds,  here  inextricably  mixed, 
mounted  up  the  north  slope  of  the  drumlin  and  were  sheared  off  on  a  plane 
which  is  almost  coincident  with  the  snrface  of  the  ch'umlin  and  which  is 
continued  south  as  the  upper  surface  of  the  fourth  till. 

It  w^ould  seem  that  the  ice  pushed  out  into  water  of  considerable  depth, 
and  so,  partly  buoyed  up,  w^as  able  to  move  over  the  plastic  clays,  producing 
a  minimum  of  erosion  and  depositing  no  till  on  the  clay ;  but  the  drumlin 
acted  as  a  resistant  substratum,  and  between  the  two  the  stratified  beds 
were  sheared  off  entirely,  the  hill  itself  was  scalped,  and  the  combined 
material  was  trailed  along  over  the  remnant  of  the  sands  down  the  slope 
(a  train  of  great  bowlders  occupying  its  lower  portion)  for  a  distance  south- 
ward from  the  drumlin  and  plainly  derived  from  it.  Masses  ranging  from 
filaments  to  large  sheets  of  the  sands  or  clays,  or  beds  containing  alterna- 
tions of  these  two,  are  contained  in  a  formless  mass  of  till  of  great  compact- 
ness, which  rests  with  a  flat  under  surface  upon  the  sands  below. 

I  have  figured  a  surface  of  this  bed  (PI.  XVIII,  fig.  3,  p.  694)  where 
it  is  just  beginning  to  mount  again  upon  the  sand  (above  D,  PI.  XV). 
The  upper  layer  of  till  is  crushed  into  the  sand  layer,  its  bowlders  plowing 
into  it  and  producing  folds  and  faults ;  while  below,  a  thick  bed  which  once 
consisted  of  clay  with  thin  sand  partings  is  as  a  whole  kneaded  into  such  a 
confused  mass  that,  over  the  broad,  smooth  siu-face  sculptured  by  the  wind, 
wherever  the  sand  layers  come  to  the  surface  they  were  eaten  out  into 
intricate  convolutions,  like  the  interior  of  the  ear. 

That  portion  of  the  sands  caught  between  the  second  and  fourth  layers 
of  till  has  all  structure  crushed  out  of  it;  but  as  the  upper  till  layer  rides 
up  onto  the  thick  mass  of  the  sands,  the  line  between  them  is  sharply  defined, 
being  gently  convex  below;  and  as  the  sands  thicken,  signs  of  bedding 
gradually  disengage  themselves  from  the  confusion  of  the  mass,  and  one 
sees  the  effect  and  direction  of  the  tlu-ust  of  the  ice  marked  with  wonderful 
clearness  in  the  contoi-ted  layers  of  the  sand.  Within  the  sands  the  layers 
are  quite  horizontal  and  undisturbed,  and  as  one  follows  each  back  toward 


688       GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

the  till,  it  is  after  a  few  undulations  thrown  into  a  series  of  sharp  zigzags 
or  short  distinct  faults,  and  the  layers  thus  brought  into  a  vertical  position 
together  or  bent  over  southward  are  then  dragged  along  beneath  the  ice, 
running  a  few  feet  parallel  to  it  and  blending  together  into  a  confused 
layer  a  foot  or  two  thick,  in  which  no  structure  is  visible.  On  the  opposite 
side,  after  the  last  cutting,  the  appearance  was  very  similar,  except  that 
the  layers  were  thrown  into  still  greater  confusion,  and  for  4  rods  all  the 
upper  half  of  the  sand,  13  feet  in  thickness,  had  been  pushed  15  or  20 
feet  southward,  the  layers  now  standing  on  their  heads  and  thrown  into 
folds  as  complex  as  the  sutures  of  an  ammonite;  and  farther  on  the  whole 
mass  has  been  wedged  in  between  the  layers  of  the  sands  in  advance,  heav- 
ing them  up  and  occupying  in  a  contorted  mass  a  great  triangular  space 
beneath  them.  The  till  rides  over  the  whole,  and  every  layer  of  the  con- 
torted mass  as  it  comes  up  from  below,  as  well  as  of  that  thrown  up  by  the 
underthrust  portion,  bends  over  southward  beneath  it  as  the  smoke  curls 
over  the  chimney  edge  in  a  strong  wind.  As  the  till  continues  southward 
over  the  sands  it  moves  parallel  with  their  lamination  and  disturbs  them  very 
little,  and  at  last,  as  it  thickens  downward,  it  cuts  across  them  at  a  low  angle, 
and  the  layers  just  below  run  on  continuously  and  show  no  signs  of  any 
effect  from  the  ice. 

Where  the  fourth  till  rising  over  the  sands  is  cut  off  by  erosion  it  is 
already  largely  composed  of  the  contorted  clays. 

Southward,  across  the  ravine,  the  surface  occupied  by  the  ice  sinks 
into  a  gentle  depression  and  rises  over  the  pink  sands  and  goes  down 
below  the  level  of  the  ciitting  near  its  south  end.  It  is  a  surface  and  noth- 
ing more,  and  in  this  long  distance  south  of  the  brook  ravine,  as  well  as  in 
the  equally  long  distance  north  of  the  di'umlin,  no  trace  of  till  is  found  upon 
it.  Only  in  the  remaining  space,  from  the  drumlin  south,  the  stratum  of  till 
is  carried  forward  along  this  plane,  and  it  is  unfortunate  that  its  ending  is 
not  to  be  observed  in  a  satisfactory  way,  owing  to  erosion.  It  is,  therefore, 
not  strictly  proved  that  this  plane  is  continuous,  but  the  identity  of  the  beds 
north  and  south  of  the  drumlin  makes  this  highly  probable,  and  an  inspec- 
tion of  the  section  will  show  it  to  be  the  only  simple  supposition,  any  other 
requiring  an  additional  recession  and  advance  of  the  ice. 

Everywhere  below  this  plane  the  clays  are  variously  contorted,  as  in 
the  reach  north  of  the  drumlin;  often  clay  and  sand  are  curiously  molded 


THE  CAMP-MEETING  CUTTING.  689 

t()>;i'tlic'r,  and  iiuiuecliatel}'  abo\e  it  the  newer  clay  or  saiul  is  wholly  uudi,s- 
turbed  to  the  surface  of  the  terrace.  Also,  in  many  masses  of  the  laminated 
clays  a  beai;tiful  jiressure  cleavage  has  been  developed,  a  series  of  fine, 
closely  apin-oximated  slip  faults  making-  a  large  angle  with  tlie  lamination, 
and  dip})ing  sharply  northward  in  the  direction  toward  which  the  pressure 
came.  The  section  shown  in  PI.  XVII  (p.  692),  taken  from  a  similar 
locality,  uiight  have  been  many  times  exactly  duplicated  in  the  first  300 
feet  south  of  the  brook. 

I  assume  this  work  to  have  been  done  by  the  advance  of  a  glacier  into 
the  water,  and  not  by  icebergs,  because  only  a  single  great  body  of  ice 
moving  over  the  soft  mass  of  clays  could  have  planed  them  down  to  so  true 
a  level  except  when  the  protuberance  of  the  di-umlin  caused  an  irregularity 
in  its  action,  and  the  great  disturbance  of  the  clay  and  subjacent  sands  for 
a  depth  of  above  20  feet  over  so  large  a  space  would  indicate  a  mass  of 
very  considerable  thickness  which  was  pushed  over  the  surface  and  not 
simply  carried  forward  by  the  current.  Except  for  these  reasons,  I  do  not 
see  why  a  continuous  mass  of  floe  ice  might  not  have  done  the  work,  for 
the  scratched  bowlders  in  the  till  layer  seem  to  have  been  derived  from  the 
earlier  till  of  the  drumlin. 

The  up]ier  sands  and  clays. — Above  the  line  of  disturbance  a  heavy 
layer  of  coarse  sands,  grading  southwardly  into  laminated  clays,  smoothes 
over  the  irregularities  of  this  surface  and  builds  up  the  terrace  to  its 
completion.  Commencing  at  the  north  end,  the  sands  dip  sharply  south- 
ward and  represent  plainly  an  advancing  delta  front  or  growing  sand 
bank,  the  sands  having  been  pushed  over  its  surface  and  deposited  upon 
its  southern  slope. 

In  the  central  portion,  over  the  more  irregular  surface  of  the  fourth  till, 
these  sands — which,  where  the  till  ends  abruptly,  I  have  already  described 
as  deposited  continuously  against  the  southern  termination  of  the  latter,  and 
as  thus  being  continuous  with  the  sands  below  the  till — are  carried  on  in 
broad,  more  nearly  horizontal  sheets,  with  finely  developed  flow-and-plunge 
structure. 

Southward,  beyond  the  brook  ravine,  these  horizontal  sands  are  capped 
by  a  thick  upper  layer  of  cross-bedded  sands  which  dips  sharply  south  and 
which  probably  represents  the  further  advance  of  the  delta  or  bank  from 
the  north,  the  intermediate  connecting  portion  having  been  removed  by 

MON  XXIX 44 


690  GEOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 

erosion.  In  this  lower  horizontal  bed  the  alternation  of  coarser  and  finer 
layers  is  very  marked,  and  southward  the  finer  layers  gradually  change  to 
clay,  while  the  coarser  grow  thinner  and  finer  and  at  last  run  out  or  blend 
with  the  clay  layer  forming  its  lower  and  sandier  third.  At  the  same  time 
the  boundary  between  the  horizontal  and  cross-bedded  portions  of  the  bed 
rises  slowly  southward,  since  each  layer  of  the  latter  coming  to  the  bottom 
of  its  slope  bends  sharply  to  a  horizontal  position,  and,  gradually  dwindling 
to  become  the  sandy  portion  of  a  clay  layer,  runs  on  between  layers  of  the 
clay,  which,  coming  from  the  south,  bend  at  the  foot  of  the  slope,  rise  up 
for  a  distance  upon  it,  and  grade  into  a  layer  of  finer  sand  which  forms  the 
upper  part  of  the  sloping  sand  layer.  Thus,  going  south,  the  horizontal 
layers  gain  at  the  expense  of  the  cross-bedded  layers  above,  and  the  clays 
gain  at  the  expense  of  the  coarse  delta  sands,  and  one  has  the  clearest 
illustration  of  the  blending  of  the  shore  sands  and  the  deep-water  clays  of 
the  Champlain  epoch,  and  evidence  of  their  synchronism  with  the  later 
events  of  the  Glacial  epoch. 

r£sum:6. 

The  facts  detailed  in  the  above  section  enable  us  to  construct  the 
following  pictures  of  the  succession  of  events  over  this  area: 

1.  The  formation  of  a  drumlin  as  a  part  of  the  ground  moraine  of  the 
first  or  great  glacier. 

2.  The  recession  of  the  ice  to  allow  of  the  formation  of  the  bowlder 
bed  which  lies  at  the  foot  of  the  drumlin  and  may  be  a  terminal  moraine, 
or  may  be  due  to  water  action  concentrating  it  from  the  drumlin  itself. 

3.  The  formation  of  a  true  sea  beach  of  great  extent — the  pink  sands. 

4.  A  second  advance  of  the  ice,  rising  over  the  drumlin  and  eroding 
the  frozen  beach  sands. 

5.  The  second  recession  of  the  ice,  and  the  deposition  by  the  flood 
waters,  from  its  melting,  of  a  great  body  of  sands. 

6.  The  rise  of  these  waters  so  that  an  equally  great  body  of  clays 
was  deposited  upon  the  sands. 

7.  A  third  minor  advance  of  the  ice  over  these  clays,  molding  them 
into  the  sands  below,  removing  them  entirely  over  the  drumlin,  and  south 
of  it  for  a  long  distance  gouging  deeply  into  the  sands  and  covering  them 
with  a  layer  of  till  derived  largely  from  the  drumlin,  finally  riding  up  onto 


U.   9.    QEOLOOICAL  fiUHVEV 


MONOGRAPH  XXIX      PL.   XVI 


^ 


■^''^  ^ 


I        '  rf — 


\ 


\,^ 


SURFACE  OF  ICE-CONTORTED  CLAYS  SMOOTHLY  CUT   WITH  A   KNIFE,    EAST  OF  J.    RYAN'S   HOUSE,   HATFIELD,     NATURAL  SIZE. 


SECTION  OF  CLAYS  IN  HATFIELD.  691 

the  c-lays  ag-aiii,  and  being  buoyed  up  and  carried  off  southward  by  the 
flood  waters,  which  still  covered  the  clays  in  considerable  depth. 

8.  The  continued  deposition  of  the  flood  sands  in  waters  somewhat 
lowered  on  the  recession  of  the  ice,  so  that  coarse  sands,  with  flow-and- 
plunge  structure,  are  laid  down,  obliterating  the  irregularities  of  the  sur- 
face and  completing  a  ten-ace  of  apparently  simple  structure. 

The  drumlin  (1)  must  represent  the  work  of  the  general  glaciation. 
The  bowlder  bed  and  the  pink  sands  (2  and  3)  must  represent  an  inter- 
glacial  period  of  sufficient  length  to  allow  of  the  long-continued  and  imin- 
terrupted  presence  of  a  large  lake  or  estuary,  and  to  make  this  possible 
the  ice  must  have  receded  far  north  of  this  point  in  the  valley.  The 
events  of  4  to  7  indicate  a  second  advance  of  the  ice,  with  minor  oscilla- 
tions, during  the  last  of  which  the  end  of  the  valley  lobe  of  the  glacier 
was  tlu-ust  out  into  the  waters  which  then  filled  the  valley  and  by  which 
the  laminated  clays  were  being  deposited,  while  at  the  same  time  the 
high  terrace  gravels  were  gathering  along  the  shores,  a  work  which  on  the 
disappearance  of  the  ice  continued  to  the  completion  of  the  terrace. 

The  discovery  of  isolated  pockets  of  glacial  ddbris  and  disturbed 
patches  at  various  places  in  the  clays  farther  south,  which  must  be  referred 
to  icebergs  or  ice  floes  (described  in  the  following  section  on  the  Cham- 
plain  clays  of  the  Iladley  Lake),  and  of  arctic  plants  also  in  the  same 
clays,,  completes  the  picture  of  the  events  of  this  time,  and  indicates  that 
the  Champlain  clays  and  sands  were  here  in  part  synchronous  with  the 
Glacial  period. 

SECTION   OP   CLAYS   IN   HATFIELD    SHOWING   GREAT    DISTURBANCE  AND    PRESSURE 

CLEAVAGE. 

About  3  miles  northeast  of  the  section  last  described  (within  the 
same  portion  of  the  Connecticut  Valley,  bounded  on  the  west  by  the  crys- 
talline rocks  and  on  the  east  by  the  long  ridge  of  Mount  Warner,  so  that 
it  is  in  a  sense  a  continuation  of  the  Deerfield  Valley),  at  the  southern  foot 
of  the  red  sandstone  hill  which  rises  north  of  the  village  of  Hatfield,  a 
small  opening  was  made  in  the  clays,  which  reproduced  exactly  the  upper 
level  of  disturbance  of  the  Camp  Meeting  section.  The  section  was  33 
feet  east  of  the  first  house  westward  from  the  hotel  on  the  lu-st  road  south 
from  the  ferry. 


692  GBOLOaY  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 

Above  a  liorizontal  line  the  clays  were  horizontal  and  normal  in  every 
respect;  below  this  they  were  extremely  contorted,  as  indicated  in  PI.  XVI, 
showing  a  smoothed  surface  about  4^  inches  square.  Where  the  contor- 
tion was  less  pronounced,  about  2  feet  below  the  plane  of  disturbance, 
in  a  layer  with  a  thickness  of  1  foot  and  a  length  of  15  feet,  a  beautiful 
pressure  cleavage  was  developed,  superinduced  upon  the  original  lamina- 
tion (PL  XVII)  in  the  whole  mass  of  the  clays  along  parallel  planes  2  to 
4"""  apart  and  dipping  32°  N.  Every  stage  in  the  series,  from  a  slight, 
sharp  monoclinal  fold  affecting  all  the  laminae  along  a  single  plane  to  the 
shearing  off  of  the  laminse  by  small  parallel  slip  faults,  could  be  followed, 
and  the  clays,  parting  easily  along  the  lamination  and  cleavage  planes, 
broke  up  into  a  mass  of  long  pencils. 

The  more  marked  fissures  are  about  6  to  the  inch;  between  these  again 
are  finer  ones,  making  the  whole  number  about  18  to  the  inch.  Along 
these  the  clay  is  very  often  slightly  faulted;  in  one  case  the  slip  amounts 
to  an  inch.  The  newly  formed  cleavage  layers  have  undergone  decided 
compression  and  distortion,  which  is  brought  out  clearly  by  the  difference 
in  color  of  the  upper  and  under  portion  of  the  original  laminae,  so  that  in 
tracing  the  dai'k  bands  across  the  several  cleavage  planes  we  find  them 
moi'e  or  less  separated  into  parts  placed  slightly  en  Echelon  by  the  con- 
tinued faulting  in  one  direction,  and  these  pai'ts  variously  elongated  and 
flattened  out  parallel  to  the  plane  of  cleavage.  We  may  assume  the  plane 
of  this  incipient  cleavage  to  be  noi'mal  to  the  direction  of  pressure.  A 
second  system  of  distant  fault  planes  occurs  at  right  angles  to  the  first, 
which  are  more  distant  from  each  other  and  have  greater  tln-ow,  showing 
that  the  parts  of  the  bed  slipped  slightly  on  each  other  in  the  direction 
of  the  pressiu-e. 

The  locality  is  125  feet  above  sea,  and  thus  somewhat  lower  than 
the  preceding'  section,  but  it  lies  out  in  the  valley,  where  the  clays  did  not 
reach  so  great  a  height  as  on  its  borders,  and  the  disturbance  must  have 
been  very  nearly — I  think  it  may  be  assumed  to  have  been  exactly — syn- 
chronous with  the  last  disturbance  of  the  previous  section.  Its  position 
under  the  lee  of  a  prominent  hill,  protected  from  icebergs  and  floe  ice, 
would  also  point  to  a  continuous  mass  of  glacial  ice  as  the  agent  of  its 
formation. 


U.    S.   QCOLOQICAL  BURVEY 


MONOORAPH    XXIX       PL.    XVII 


MOTfON  OF  THE  ICE 


JOINTS  AND   FAULTS   IN   LAMINATED  CLAY,    PRODUCED   BY  THE  WEIGHT  OF  THE    ICE. 


PLATE  XVIII. 


693 


PLATE    XVIII. 

THE  WAPPING  AND  CAMP-MEETING  CUTTINGS. 

Fig.  1. — Section  of  the  fine-grained,  contorted  sands  at  the  Wapping  cutting  on  tlie  Canal  Railroad, 
in  Deerfield. 

Fig.  2. — Section  on  the  west  side  of  the  Camp  Meeting  cutting,  between  the  south  end  of  the  drumlin 
and  the  hrook,  showing  the  fourth  advance  of  the  ice  into  the  second  sands.  It  is  opposite  to 
the  portions  G  and  I  on  the  east  section,  3  rods  distant  from  it.  It  is  represented  by  the  discon- 
nected mass  of  till  above  I. 

Fig.  3. — Enlargement  of  jiart  of  PI.  XV  (p.  678)  at  a  point  halfway  between  G  and  H,  and  above  the 
second  sands,  where  two  large  bowlders  appear.  It  shows  the  passage  of  the  fourth  ice  over 
the  older  clays,  here  nearly  all  eroded,  and  the  thrust  of  the  bowlders  into  the  clays,  and  the 
kneading  together  of  the  clays  and  subjacent  sands.  The  wind  erosion  of  the  sand  has  pro- 
duced deep,  ear-like  depressions  in  the  lower  part  of  the  frozen  wall. 
694 


18 


.    S.   GEOLOGICAL  6URVEV 


MONOGRAPH  X 


}ici/fjin^  CH.L,  JJe^r  fteZd. . 


COy£^/7SO 


COl^£R£D 


^  AND 
r^  SANO 


THE   WAPPING   AND  CAMP   MEETING  CUTTINGS, 


SECTIONS  OF  TERRACES  AND  LAKE  liOTTOMS.  695 

THE    WAITING   CU'I'TINC. 
CONTORTKn   SANDS   AT  TlIK   CUTTINCi   AT   WAI'I'INO,    IN    DKKRFIELI). 

This  section,  tig-urecl  on  PI.  XVIII,  fig-.  1,  was  exposed  in  the  works  for 
the  extension  of  the  New  Plaven  and  Northampton  Raih-oad  northward,  2 
miles  south  of  Deerfield  Station,  at  the  same  time  with  the  Camp  Meeting 
cuttinff  described  above.^  The  deha  of  the  Deerfield  River  in  the  Connec- 
ticut  Lake  (p.  634)  extended  out  as  a  broad,  flat  alluvial  fan  from  the 
mouth  of  the  river  gorge  in  the  crystalline  rocks  at  West  Deei-field,  reaching 
clear  across  the  lateral  Deerfield  Valley  to  the  foot  of  the  trap  ridge.  The 
northern  half  of  this  delta  has  been  removed  by  the  later  erosion  of  the 
Deerfield  River,  and  from  the  northern  rim  of  the  remainder  one  looks 
down  north  into  the  deep  basin  thus  formed.  As  the  railroad  approached 
this  from  the  south  its  grade  was  lowered  and  a  deep  cut  was  made,  so  that 
it  could  pass  across  this  basin  by  a  high  embankment.  The  section  given 
was  taken  from  the  west  wall,  and  is  thus  the  north-south  section  through 
the  middle  of  the  delta,  and  just  opposite  the  mouth  of  the  gorg-e  of  the 
river.  It  is  made  up  of  fine  to  very  fine,  well-sorted  sands,  in  layers  1""™ 
thick  and  made  more  distinct  by  the  infiltration  of  iron.  Coarser  layers, 
drying  white,  and  thus  standing  out  prominently,  occur  3  to  4  inches  apart, 
and  still  coarser  and  thicker  ones  of  the  same  character  about  one-half  inch 
apart;  these  are  represented  by  the  heavy  lines  in  the  drawing,  and  they 
render  the  contortions  visible  for  a  long  distance. 

The  length  of  the  section  is  278  feet,  the  greatest  height  45  feet  above 
the  railroad.  Toward  the  north  end  the  whole  thickness  of  the  sands  in 
the  section  is  crumpled,  manifestly  by  a  strong  force  coming  from  the 
north,  the  disturbance  of  the  sands  being  greatest  in  the  northern  half  of 
the  section  and  in  the  lower  portion  of  this  half,  and  appearing  more  in 
detached  patches  in  the  southern  part.  The  cutting  was  carried  along  the 
west  side  of  a  brook  valley  running  north,  and  the  rain  washed  a  gulch  from 
the  cutting  down  to  the  level  of  this  brook,  exposing  the  fine  sands  for  20  to 
25  feet  below  the  base  of  the  section.  The  disturbance  lessens  downward  and 
the  base  of  the  sand  is  more  clayey  and  rests  unconformably  upon  coarse, 
reddish,  cross-stratified  sands  derived  manifestly  from  the  sandstone,  while 
the  upper  sands  are  as  plainly  derived  from  the  crystalline  rocks  of  the  west. 

The  line  of  junction  of  the  two  sands  is  extremely  irregular,  the  lower 
beds  having  been  much  eroded  before  the  deposition  of  the  upper,  but  the 

'  See  E.  Hitchcock,  Geol.  Mass.,  1841,  p.  363. 


696  GEOLOGY  OF  OLD  HAMPSHIRE  OOUl^TY,  MASS. 

junction  is  such  as  can  have  been  formed  only  by  the  forcible  kneading 
together  of  the  beds.  A  little  farther  south,  on  the  border  of  the  delta  at 
the  house  of  Captain  Briggs,  the  red  sands  come  to  the  surface  in  a  long 
knoll.  They  are  finely  cross-stratified  and  dip  south  with  an  angle  as  high 
as  35°.  At  the  cutting  these  under  sands  are  much  jointed  and  faulted,  as 
if  they  had  been  subjected  to  pressure  before  the  deposition  of  the  upper 
sands.  I  identify  these  lower  sands  with  the  pink  sands  of  the  Camp  Meet- 
ing cutting  (p.  680),  and  believe  them  to  be  a  remnant  of  beds  deposited  after 
the  first  recession  of  the  glacier,  while  the  Deerfield  Valley  was  still  sealed 
up  by  the  ice,  which  escaped  the  erosion  of  the  second  advance  of  the  ice 
and  on  its  recession  were  covered  by  the  sands  of  the  Deei-field  delta. 

It  is  not  clear  to  me  what  could  have  caused  the  extensive  disturbance 
of  the  upper  sands.  This  disturbance  is  to  be  seen  in  the  upper  side  of  the 
road  running  parallel  to  the  cutting,  several  hundred  yards  to  the  east.  It 
is  at  its  maximum  at  the  north  end  of  the  opening,  where  the  sands  have 
been  removed  by  the  erosion  of  the  river  and  extended  an  unknown  dis- 
tance to  the  north  in  the  beds  before  their  removal. 

On  the  north  side  of  the  Deerfield  RiA^er  basin,  a  mile  west  of  Cheapside, 
a  complete  section  of  the  sands  from  the  surface  down  to  the  till  was  quite 
normal  and  undisturbed,  as  also  on  its  northwest  border  and  on  the  island 
of  the  terrace  sands  which  rises  in  the  middle  of  the  basin.  Small  detached 
areas  of  disturbance  in  the  delta  sands  are  common  from  the  head  of  the 
latter  south  to  the  south  line  of  Deerfield,  plainly  caused  by  stranded  ice, 
but  here  a  force  of  much  greater  magnitude  was  certainly  concerned. 

I  have  described  on  page  630  the  deep,  long  depression  along  the  west 
line  of  Greenfield  in  which  Grreen  River  flows  and  which  was  occupied 
by  the  west  lobe  of  the  ice  that  fotmd  place  in  the  valley  while  the  flood 
sands  brought  in  across  Greenfield  through  the  Bernardston  strait  were 
building  up  the  high  terrace  in  Greenfield,  and  this  lobe  of  ice,  extended 
south,  would  have  come  in  contact  with  the  delta  of  the  Deerfield  from  the 
right  direction  to  have  plowed  up  the  sands  as  we  now  find  them.  The  high 
terrace  sands  are,  however,  undisturbed  right  across  its  supposed  track  west 
of  Cheapside,  and  though  these  sands  may  have  been  swept  in  a  little  later, 
their  presence  renders  this  explanation  only  remotely  probable.  Another 
possible  explanation  is  that  the  axis  of  the  delta  of  which  these  beds  form 
a  part  lay  to  the  north  of  this  spot,  and  along  this  axis  the  greater  thick- 
ness of  the  beds  caused,  by  their  weight,  a  flowing  of  their  fine  sands. 


CHAPTER    XX. 

THE  CHAMPLAIN  PERIOD  (Continued). 

THE   CHAMPIiAllSr  CLAYS. 

INTRODUCTION. 

On  the  retreat  of  the  ice  and  on  the  occupancy  of  the  basm  by  the 
flood  waters  clays  began  to  be  deposited  over  all  the  bottom,  far  from  the 
shores,  where  the  current  was  not  too  strong,  and  sands  and  gravels  accumu- 
lated off  the  mouths  of  all  the  tributaries,  and  were  moved  along  the  shore 
lines  by  the  shore  currents  and  out  into  the  deeper  water  by  the  undertow. 
The  two  deposits  are  therefore  strictly  contemporaneous,  and  their  laminse 
are  intercalated  with  each  other  at  their  point  of  junction  (see  p.  690).  The 
sands  were  pushed  in  deltas  rapidly  out  over  the  clays,  so  that  their  place 
of  junction  is  a  plane  with  small  shoreward  dip.  It  is  strictly  synchronous 
with  this  earlier  portion  of  the  flood  sands,  since,  as  detailed  in  the  last 
section,  the  increased  velocity  of  the  flood  earned  sands  out  over  the  clays 
in  every  portion  of  the  lake  bottoms,  even  in  the  most  sheltered,  like  the 
East  Street  basin  in  Amherst. 

The  scanty  otitcrops  of  the  clay,  mostly  along  river  gorges,  are  marked 
by  a  line  of  purple  dots  (1  b  c,  PI.  XXXV),  this  color  having  thus  a  litho- 
logical  value,  while  the  other  post-Tertiary  colors  on  the  map  have  rather 
an  orographic  value. 

The  great  importance  and  magnitude  of  this  terrane  can  be  seen  best 
in  vertical  sections,  as  upon  the  map  it  is  represented  only  by  thin  lines 
along  the  river  courses  and  road  cuttings  and  on  the  steep  slopes  of  ter- 
races; elsewhere  it  is  covered  by  the  succeeding  beds  of  sand. 

CLAYS  IN  THE  MONTAGUE  LAKE. 

The  clays  appear  in  great  force  above  and  below  Northfield  village, 
where  the  brooks  cut  back  in  the  lake-bottom  beds,  and  here  they  rise  233 
feet  above  sea  level.  Southward  they  appear  frequently  in  brook  cut- 
tings in  the  bottom  beds,  and  at  Northfield  Farms  they  rise  to  270  feet 

697 


698  GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

above  the  sea.  The  fat  layers  are  one-fourth  to  oue-half  inch  thick  and  6 
inches  apart.  This  great  height  was  due  to  the  rapid  advance  of  the  Millers 
River  delta  across  the  channel  farther  south,  which  checked  the  current 
to  the  north.  How  rapid  this  was  is  seen  by  the  section,  fig.  41  (p.  688), 
where  far  out  in  the  delta  the  sands  rest  directly  upon  the  rock.  As  the 
delta  was  extended  westward  its  sands  were  doubtless  carried  up  grgidu- 
ally  over  the  clays,  for  in  the  long  erosion  scarp  cut  in  the  western  face 
of  this  delta  from  Turners  Falls  around  nearly  to  Montague  village,  only  a 
small  thickness  of  sand  rests  upon  the  clays,  which  rise  to  a  height  of  about 
213  feet  above  the  sea  and  rest  upon  till  or  sandstone  with  a  thickness  of 
about  34  feet.  The  layers  average  about  1  inch,  one-half  fat  clay,  two- 
thirds  fine  sand.     (See  fig.  35,  p.  629.) 

CLAYS   IN   THE   HADLEY   LAKE. 

I  have  mentioned  an  isolated  occurrence  of  clay  ]30orly  exposed  at  a 
schoolhouse  in  the  north  of  Greenfield.  Around  Greenfield  village  the 
clays  are  in  great  force  and  rest  upon  till,  as  seen  at  the  clay  pit  in  the 
village  and  on  Fall  River  where  the  road  to  Franklin  Park  crosses  it. 
These  clays  were  continuous  through  the  notch  of  the  Deerfield  River,  and 
perhaps  also  connect  farther  north,  through  the  passage  at  the  mouth  of 
Fall  River,  with  the  Turners  Falls  clays.  Southward  they  crop  out 
abundantly  around  the  erosion  basin  of  the  Deei-field  River,  to  near  its 
soiith  end,  opposite  the  mouth  of  the  river  gorge,  where,  from  the  increased 
current  and  the  increased  material  broiight  in  by  the  river,  the  clays  are 
replaced  by  a  great  thickness  of  sand,  which,  in  the  center  of  the  basin, 
becomes  exceedingly  fine,  with  distant  clayey  partings,  as  seen  in  the 
Wapping  cutting  (PL  XVIII,  p.  694),  where  these  fine  sands  rest  discord- 
antly on  the  problematical  reddish  sands  which  are  there  described. 

Farther  south,  through  Deerfield  and  Hatfield,  the  sand  plains  are 
nowhere  cut  through  to  the  clays  below  until  the  region  of  complex 
oxbows  of  the  Connecticut  west  of  Hatfield  village,  described  later  (p.  734), 
is  reached,  where,  in  the  terrace  scarp,  the  clays  appear  in  great  force ;  only 
at  one  place,  at  a  clay  pit  near  the  pistol  factory,  is  the  substratum — here 
coarse  till — exposed. 

Southward,  beyond  the  influence  of  the  Deerfield,  the  whole  broad  bot- 
tom of  the  lake  is  underlain  by  a  continuous  stratum  of  clay  of  unknown, 


CLAYS  IN  THE  HxVDLEY  LAKE.  699 

Init  in  tilac't's  certaiiiK'  of  very  great,  thickness,  and  tlie  clay  has  done 
more  than  all  the  other  beds  to  obliterate  tlie  vei-tical  irregularities  impressed 
uiion  the  basin  by  the  ice.  It  still  underlies  tlie  whole  flood  plain  of  the 
Connecticut,  and  although  the  river  in  its  oscillations  has  cut  in  the  clay  a 
broad  and  deep  channel,  it  has  not  cut  through  to  the  base  of  the  clay 
stratum,  except  opposite  North  Hadley,- where  a  reef  of  sandstone  projects 
throuo-li,  and  at  the  knee  of  the  great  bend,  where  the  river  has  worn  into 
a  submero-ed  drumlin.  This  great  bed  of  clay  continues  southward  to  the 
Westtield  River,  where  the  conditions  of  the  Deerfield  are  exactly  repeated, 
and  the  clays  are  replaced  by  the  fine  delta  sands. 

It  extends  everywhere  under,  and  sometimes  very  far  under,  the  shore 
terrace,  notably  in  the  case  of  the  Mill  River  delta  in  Northampton,  where 
the  clays  spread  under  the  delta  deposits  clear  up  to  the  "  Bay  State,"  near 
Florence,  where  they  are  worked  in  large  brick  pits  and  rest  on  till  with  a 
thickness  of  23  feet.  There  are  also  large  pits  near  the  asylum.  It  reaches 
apparently  its  greatest  thickness  under  the  Northampton  and  Hadley 
meadows  and  in  the  East  Street  basin  in  Amherst.  At  the  Belden  silk 
mill,  near  the  station  in  Northampton,  the  clay  was  reached  beneath  a  few 
feet  of  sand,  and  its  bottom  was  140  feet  below  the  surface — that  is,  about 
12  feet  below  sea  level.  Beneath  the  clay  was  10  feet  of  red  sand. 
The  clay  was  pierced  112  feet  at  the  piers  of  the  overhead  bridge  at  the 
Northampton  station. 

The  trial  piles  at  the  Northampton  bridge  over  the  Connecticut,  heavy 
timbers  well  jointed  and  hooped,  were  driven  113  feet  below  low  water — 
that  is,  about  13  feet  below  sea  level — without  finding  bottom,  and  after 
the  pile  had  rested  in  its  place  for  the  night  the  first  blow  in  the  morning 
advanced  it  as  much  as  the  last  of  the  night  before,  which  would  have 
hardly  been  possible  in  any  material  except  a  very  plastic  clay.  The  piles 
for  all  the  piers  of  the  bridge  were  driven  30  feet  below  the  river  bottom 
in  the  same  clays  after  passing  through  the  river  gravels. 

About  1,500  feet  north  of  the  bridge  the  clays  rise  in  the  high  western 
bank  of  the  river  about  72  feet  above  low  water.  This  is  just  opposite  and 
only  a  few  yards  from  the  south  end  of  the  Camp  Meeting  cutting  (see 
p.  677),  and  the  clays  between  are  continuous.  Thus  their  maximum 
thickness  may  be  about  218  feet.  About  the  same  distance  south  of  the 
bridge  they  are  exposed  for  a  long  way  in  the  river  bank,  at  the  south  end 
of  Hadley  street,  a  locality  furnishing  fossil  leaves  (see  p.  738)  and  an 


700  GEOLOGY  OF  OLD  HAMPSHIRE  OOUl^TY,  MASS. 

abundance  of  concretions.  They  have  been  extensively  worked  near  the 
asylum  in  Northampton,  at  Rich's  brickyards  east  of  Southampton,  and  at 
Pomeroy's  yards  west  of  that  town. 

They  extend  east  from  the  river  with  the  full  width  of  the  space  between 
Mount  Holyoke  and  Mount  Toby,  rounding  Mount  Warner,  and  being  very 
near  the  surface  in  all  the  area  south  of  Mount  Warner  to  near  the  foot 
of  Mount  Holyoke,  where  wells  81  feet  deep  (Mr.  Shipman,  Lawrence  plain, 
south  of  Hadley)  and  40  feet  deep  (A.  Losey,  Nuttinsville,  Amherst)  were 
sunk  in  sand  and  fine  gravel  without  reaching  the  base  of  the  sands. 

Over  the  bottom  of  the  central  depression  the  clays,  being  near  the 
SLirface,  are  often  sandy.  The  clay  is  worked  for  bricks  at  Plainville 
(north  of  Hadley) ;  and  in  the  bottom  of  the  depression,  where  Amity  street 
crosses  the  brook,  it  was  formerly  worked.  Near  by,  at  Mr.  Stebbins's 
barn,  a  well  went  through  the  following: 

Feet. 

Fine  sand 2 

Clay 7 

Sandy  clay 13 

At  Mr.  S.  Harrington's,  in  North  Amherst,  a  well  90  feet  deep  did  not 
reach  the  bottom  of  the  clay. 

Tlie  clays  rise  high  up  oil  the  slope  of  the  Amherst  ridge  and  thin  out 
under  the  shore  gravels.  The}^  are  cut  through  by  all  wells  along  the 
slope  below,  246  feet  above  the  sea,  and  reached  their  greatest  observed 
height  in  the  col  between  the  central  depression  and  the  basin  south  of 
College  Hill,  where  they  were  exposed  by  the  Central  Railroad  cutting 
from  the  bridge  at  Main  street  east  to  the  end  of  the  cutting,  with  a  maxi- 
mum height  of  260  feet  above  sea.  (See  p.  645.)  These  clays  thicken  out 
east  into  the  land-locked  basin  south  of  College  Hill,  where  in  Champlain 
time  they  accumulated  to  great  thickness,  with  little  covering  of  sand. 

In  the  East  Street  basin  the  clays  were  also  developed  to  great  thick- 
ness, and  over  all  the  area  south  of  the  road  to  Pelliam  lie  very  near  the 
surface.  At  the  third  house  east  of  the  bridge  on  this  road  (Mr.  Hubbard's) 
a  well  was  bored  50  feet  in  clay  covered  by  8  feet  of  sand,  and  the  water 
rises  to  within  2  feet  of  the  surface.  In  a  well  on  the  south  side  of  the  same 
road  near  the  middle  of  East  Street  (Mr.  Clutia's)  this  section  was  exposed: 

Feet. 

Fine  sand : 7 

Clay 23 

Fine  quicksand 3 

Till 3 


THE  SPIUNGPIELD  LAKE.  701 

Fartlier  soutli,  where  the  road  from  the  village  crosses  Fort  River  at 
tlio  l)rick  'jitf*,  the  following-  section  was  taken  from  the  exposure  in  the  pit 
and  iVoiu  a  well  adjacent: 

Feet. 

Fine  sand 6 

Cliiy 35 

Till 

Pockets  of  pebbles  were  found  in  the  clay,  and  the  water,  very  sul- 
phurous and  irony,  came  to  within  5  feet  of  the  surface.  Fossil  leaves 
occur  here. 

CLAYS    IN   THE   SPRINGFIELD   LAKE. 

There  are  no  brickyards  in  Agawam  and  West  Springfield,  though  the 
clay  crops  out  at  Riverside.  There  are  extensive  brickyards  along  the  east 
side  of  the  river  at  the  following  points:  Above  the  Holyoke  bridge;  at 
Willimansett;  in  the  northern  part  of  Springfield;  and  especially  beside 
the  Boston  and  Albany  Railroad  in  the  southern  part  of  Springfield,  and 
across  the  line  in  Longmeadow. 

Eastwardly  the  clays  are  deeply  covered  by  the  thick  sands  of  the 
Chicopee  River  delta,  which  extend  across  Wilbraham  and  Springfield. 

CONTACT  OF  THE  CLAYS  UPON  THE  TILL. 

The  section  exposed  at  the  hoe  factory  in  Northampton,  and  illustrated 
in  fig.  31,  p.  540,  not  only  shows  the  contact  of  the  till  upon  the  sandstone 
and  the  upper  surface  of  the  former,  upon  which  the  ice  rested,  but  also 
demonstrates  that  the  deposition  of  the  clay  followed  immediately  upon  the 
disappearance  of  the  ice,  under  circunastances  which  indicate  that  the  ice 
cotild  not  have  melted  in  place  upon  the  till;  nor  could  the  till  have  been 
exposed  to  subaerial  erosion  before  the  clay  began  to  be  deposited.  In  the 
former  case  a  loose  deposit  of  upper  till  must  have  intervened  over  the  till 
and  sandstone  alike;  in  the  latter,  the  till  would  have  been  eroded  below 
the  level  of  the  sandstone,  and  the  common  uniformly  curved  surface  would 
not  have  been  preserved. 

It  seems  to  me  probable  that  at  this  time — ^the  end  of  the  Glacial  period 
for  this  basin — the  waters  stood  over  this  place,  which  is  about  135  feet  above 
the  sea — and  of  course  over  the  whole  basin — at  a  height  so  great  that  the 
ice  was  at  last  buoyed  up  and  floated  away,  and' the  clays  began  immediately 
to  be  deposited  upon  the  surface  thus  abandoned. 


702  GEOLOGY  OP  OLD  HAMPSHIRE  COUNTY,  MASS. 

The  clays  were  grayish-blue,  very  fine,  "fat"  clays,  agreeing  exactly 
with  those  worked  in  the  large  brickyards  a  few  rods  south. 

When  both  the  clay  and  the  till  were  wet  the  sharp,  curved  line  of 
junction  was  inconspicuous  at  a  little  distance,  the  whole  surface  presenting 
a  uniform  dark  bluish-gray  color,  but  above  the  line  a  cane  could  be  easily 
tlu'ust  into  the  clays  for  its  full  length,  while  the  blow  of  a  hammer  would 
not  make  much  more  imjoression  upon  the  till  than  upon  the  neighboring 
sandstone. 

The  section  is  situated  far  within  the  limits  of  the  high  terrace  and  is 
exposed  by  the  deep  erosion  of  this  terrace  by  the  Mill  River,  which,  in 
cutting  down  to  this  level,  has  carried  its  gravel  beds  over  the  whole, 
making  the  upper  horizontal  stratum  in  the  diagram.  If  we  restore  the 
terrace  here  to  its  condition  before  it  was  affected  by  the  erosion  of  the 
river,  we  shall  need  25  to  30  feet  of  clay  resting  on  the  till  and  covered 
by  35  to  40  feet  of  sand  to  bring  the  level  up  to  200  feet  above  the  sea, 
which  is  the  height  of  the  terrace  over  this  area.  The  clays  are  exposed 
with  this  thickness  in  the  face  of  the  high  terrace  on  both  sides  of  the 
stream.  When  the  ice  disappeared,  however,  and  the  deposition  of  the  clay 
began,  this  was  a  deep  depression  between  the  "drumlins"  of  till  upon 
which  the  hospital  and  Smith  College  stand,  opening  southward  into  the 
main  basin. 

In  another  section,  from  the  Canal  Railroad,  exposed  just  west  of  the 
South  Street  bridge  in  Northampton,  the  clays  rest  also  directly  upon  the 
stony  till,  and  although  greatly  disturbed  by  stranded  ice  and  mixed  with 
material  dropped  from  it,  there  is  everywhere  at  least  a  foot  of  the  fine  clay, 
undisturbed,  intervening  between  the  till  and  the  horizon  where  coarser 
iceberg  material  appears.  In  many  of  the  clay  pits  the  base  of  the  clay  is 
reached,  and  it  is  always  in  contact  with  the  till. 

In  the  Central  Raih'oad  cutting  south  of  College  Hill,  in  Amherst,  the 
following  section  was  exposed  beneath  the  bridge  (figs.  37,  38,  and  39, 
p.  645) :  On  the  till,  which  appeared  just  above  the  bottom  of  the  cutting, 
but  arose  westwardly  to  occupy  nearly  its  whole  thickness,  rested  coarse, 
cross-bedded  sands,  which  had  been  swept  fi'om  the  west  over  its  surface, 
and  which  reached  a  thickness  of  3  feet;  upon  these  rested  clay,  reaching 
a  thickness  of  about  7  feet,  in  the  lower  half  banded  in  layers  1  inch  thick, 
with  fine  sand  partings;  many  layers  resting  below  between  undisturbed 


TllK  STRUOTURE  OF  THE  CLAYS,  703 

laA'ors  wore   contorted  tor  a    sliort   distance   in   a    most  complex   way,   as 
indicated  in  tijj;-.  38,  and  on  a  larger  scale  in  fig-.  39. 

It  seems  clear  that  the  friction  of  the  current  was  sufficient  to  slide  the 
layer  of  tenacious  cla}-  upon  its  substratum  of  fine  sand  for  a  short  distance 
and  cniiiiplc  it  up,  for  each  of  these  crumpled  layers  is  covered  by  an 
unusually  thick  and  somewhat  coarser  film  of  sand.  The  layers  grow 
thinner  toward  the  surface,  and  the  upper  3  feet  is  an  unctuous,  nonlami- 
nated  clav.  It  is  capped  by  the  coarse  beach  gravel,  which  rises  to  the 
surface.  This  is  the  only  occurrence  of"  sand  beneath  the  clay  I  have  seen 
in  the  basin,  though  the  fine  sands  of  the  Wapping  cutting  (see  p.  695)  are 
so  exactly  equivalent  to  the  clays  that  the  red  sands  upon  which  they  rest 
uncomforiuably  may  come  in  the  same  category.  It  is  also  the  highest  point 
reached  by  the  clays  (251  feet),  and  here  the  till  was  for  a  short  time  swept 
by  a  strong  current  from  the  main  valley  into  the  East  Street  basin  before 
the  deposition  of  the  clays  began. 

THE  STRUCTURE  OF  THE  CLAYS. 

The  upper  horizontal  laminse  in  PI.  XVI  (p.  690),  from  Hatfield,  illus- 
trate the  minute  structure  of  the  Champlain  clays.  Over  all  the  central 
portion  of  the  basin  they  are  uniformly  thin,  even  bedded,  and  horizontal, 
show  a  regular  alternation  of  fat  and  lean  portions,  and  on  drying  separate 
easily  into  layers,  each  of  which  consists  of  a  sandy  part  below  and  a  fat 
part  above,  which  grade  into  each  other.  The  brickmakers  call  the  "fat" 
portion  clay  and  the  "lean"  portion  sand,  distinguishing  more  closely  than 
the  geologist. 

On  the  river  bank  at  Hadley  the  lower  and  much  the  larger  portion  of 
each  layer  is  an  extremely  fine  sandy  clay,  drab  colored  when  wet,  pale 
buff  when  dry,  composed  of  a  fine,  sharp,  quartz  sand,  0.15  to  0.24""  in  size, 
and  of  kaolin  in  irregular  elongated  particles,  affecting  reniform  and  sausage- 
like shapes  from  flocculation.  This  passes  rather  abruptly,  by  the  lessening 
of  the  percentage  of  quartz  grains,  into  an  upper  and  finer  portion,  which  is 
generally  one-fourth  to  one-fifth  the  thickness  of  the  lower  portion,  of  dark 
bluish-gray  color  when  wet  and  olive  green  when  dry.  It  contains  a  small 
proportion  of  kaolin,  the  rest  being  very  fine  quartz  grains.  Its  average 
grain  is  0.0008  to  0.0016"™  for  the  kaohn. 

In  a  specimen  taken  from  the  bank  of  Fort  River,  below  Mill  Valley, 
in  Amherst,  where  the  olive-green  upper  portion  was  0.7"""  thick,  the  coarser 


704  GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

lower  pai't  0.3"",  measurements  of  grains  from  the  top  of  the  layer  gave 
0.0018  to  0.00735"™,  from  the  middle  of  the  lower  portion  0.00735  to 
0.0294"",  and  from  the  bottom  0.0735  to  0.147"". 

At  the  Hatfield  locality  (PL  XVI,  p.  690)  in  each  layer  the  lower  two- 
thirds  is  much  coarser  than  the  upper  third,  and  is  in  reality  an  exceedingly 
fine  sand,  under  the  microscope  appearing  like  a  quartz  sandstone,  the 
grains  angular,  0.0037  to  0.0075""  in  diameter.  Besides  quartz,  there  occur 
feldspar,  mica,  and  a  few  acicular  microlites.  The  lower  portion  was  olive 
green  when  wet,  drab  when  dry.  The  upper  portion  showed,  both  wet 
and  dry,  a  darker  shade  of  the  same  color,  but  the  difference  was  much 
more  marked  when  it  was  wet.  Under  the  microscope  it  appeared  like 
the  other  portion,  except  that  it  was  much  finer ;  but  there  were  present 
many  minute  opaque  particles  of  koalin,  oblong  or  sausage-shaped,  which 
showed  the  Brownian  movement  finely.  The  size  of  the  quartz  grains 
was  0.0011  to  0.002"". 

THE   STJBPACE   OF   THE   LAYERS. 

In  some  cases  the  layers  are  joined  so  closely  that  one  can  hardly  dis- 
tinguish the  line  separating  two  laminae  from  that  dividing  the  finer  and 
coarser  portions  of  a  single  one.  Grenerally  there  is  at  least  a  thin  film  of 
rust,  showing  that  the  waters  have  sought  out  the  planes  of  separation 
between  the  layers,  as  affording  them  easier  passage,  and  the  clays  on  dry- 
ing split  readily  along  these  planes. 

On  these  delicate  surfaces  one  detects  rarely  the  undulating  tracks  of 
worms  or  the  small  coriaceous  leaves  of  arctic  plants.  On  other  surfaces 
a  delicate  ripple  marking  appeared,  regularly  arranged — broadly  elliptical 
depressions  several  inches  long  and  of  so  slight  depth  that  their  presence 
might  easily  have  been  overlooked  if  they  had  not  been  brought  out  by  a 
film  of  reddish  sand,  which  filled  the  hollows  and  was  mostly  wanting  upon 
the  surrounding  ridges.  The  depth  of  the  depressions  was  often  only  equal 
to  the  thickness  of  a  single  grain  of  the  fine  sand.  This  surface  sand  pre- 
served, also,  the  delicate  water-drift  structure  impressed  upon  it  by  the 
current.  The  rijjple  marks  and  these  drifted  sands  together  register,  in 
each  case  where  they  occur,  a  flood  so  considerable  as  to  give  the  whole 
body  of  water  in  the  lake  a  current  strong  enough  to  enable  it  to  drift 
along  the  bottom  slieets  of  the  red  sands  from  the  border  beds  farther 
north  out  to  this  point  in  the  very  middle  of  the  lake. 


THE  STKUOTUllE  OF  THE  CLAY.  705 

THE  LATERAL  PASSAGE  OF  THE  CLAYS  INTO  THE  HIGH  TERRACE  SANDS. 

At  the  soutli  end  of  tlie  Camp  Meeting  cutting  (PI.  XV,  j).  fi78)  the 
whole  thickness  of  the  cutting  was  in  clay  and  the  plane  of  junction  dipped 
north  with  a  low  angle,  so  that  the  clays  ran  far  under  the  sands  and  dis- 
ai)peared  below  the  level  of  the  cut.  The  sands  were  part  of  a  delta  or 
bar  front,  advancing  southward  and  dipping  sharply  in  this  direction  in 
quite  thick  layers  which  at  the  bottom  of  the  slope  became  horizontal,  thin- 
ning rapidly  and  running  out  between  the  clay  layers,  becoming  finer 
o-rained  and  disappearing  or  merging  with  the  coarser  portion  of  a  layer  ot 
the  clay.  On  the  other  hand,  some  layers  of  the  clay  ran  up  the  slope 
between  the  sand  layers  for  a  distance,  becoming  coarser  and  merging  with 
an  upper  and  finer  portion  of  the  sand  layer. 

THE   PASSAGE   OF  THE   CLAYS  INTO   THE   SANDS  ABOVE. 

The  delicate  partings  of  sand  described  above  (p.  704)  increase  in 
number  and  in  thickness  as  one  approaches  the  upper  surface  of  the  clay, 
and  finally  effect  the  passage  of  the  one  into  the  other. 

In  the  river  ba.nk  below  Hadley,  the  locality  which  for  the  most  part 
furnished  the  type  of  the  preceding  descriptions,  the  upper  portion  of  the 
clays  has  been  carried  away  by  the  river,  and  its  sands  rest  unconformably 
upon  the  eroded  surface  of  the  clays.  The  true  passage  beds  are  best 
exposed  at  the  extreme  south  end  of  the  Camp  Meeting  cutting  (PI.  XV, 
p.  678). 

Nine  feet  below  the  upper  surface  of  the  clay  these  partings  are  one- 
sixteenth  of  an  inch  thick,  of  coarse  red  sand,  and  are  very  frequent,  so 
as  to  give  the  blue  clay  a  reddish  tinge.  This  continues  upward  for  3 
feet,  when  a  4-inch  layer  of  coarse  red  sand  intervenes,  which  is  followed 
by  a  band  5  feet  thick,  where  the  red  sand  and  clay,  alternating  in  fine 
but  regular  layers,  are  in  about  equal  quantity.  The  whole  is  capped  by 
another  thick  layer  of  red  sand,  which  grades  into  the  ordinary  buff  flood 
sands,  here  only  4  feet  thick. 

Opposite  the  Hatfield  Hotel  begins  a  long,  narrow  remnant  of  the  old 
lake  bottom,  which,  by  a  curious  freak  of  the  river,  has  been  left  intact, 
while  the  river  has  cut  away  on  all  sides  of  it.  This  preserves  the  old  sur- 
face of  the  clays  and  the  passage  beds  into  the  sands  above.  There  is  here, 
within  4  feet,  a  very  gradual  passage  from  the  fine  clays  into  fine,  white 

MON  XXIX 46 


706  GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

sands,  locally  reddened  with  iron  in  the  lower  part,  where  the  waters  have 
stood  on  tbe  surface  of  the  clays. 

Over  all  the  broad  plain  south  of  Mount  Warner,  over  which  the  road 
from  Amherst  to  Northampton  runs,  the  passage  beds,  seem  to  me  to  be 
present,  and  the  clays  seem  still  to  retain  their  full  height. 

EXPLANATION  OF  THE  STRUCTURE  OF  THE  CLAYS. 

In  introduction  of  this  explanation  a  further  peculiarity  of  the  clays 
may  be  here  considered. 

While  the  "fat"  portions  of  the  clay  layers  are  very  uniform  in  thick- 
ness and  grain,  the  variation  in  the  thickness  of  the  layers  depends  upon  a 
thickening  or  thinning  of  the  sandy  portions  of  these  layers,  which  may  or 
may  not  be  accompanied  by  a  corresponding  change  in  the  grain  of  the 
latter.  At  times  the  fat  laminae  separate  and  take  in  between  them  12  to  16 
inches  of  a  sand  but  little  coarser  than  that  of  the  coarse  portion  of  the 
layers  at  the  Hadley  locality,  as  is  the  case  in  a  large  portion  of  the  Wap- 
ping  cutting.     At  other  times  the  grain  increases  to  medium  or  coarse. 

The  fat  laminae  seem  to  be  purely  a  sediment  of  matter  held  in  suspen- 
sion when  there  was  scarcely  a  trace  of  current,  the  lean  laminae  to  contain 
in  gradually  increasing  proportion  the  fine  material  carried  over  the  bottom 
by  the  friction  of  a  slow  current,  which  was  regularly  intensified  for  the 
formation  of  the  thin  films  of  sand  which  separate  the  layers.  One  finds 
these  clays  as  regular  as  a  pile  of  thin  deals  over  all  the  basin,  and  I  imag- 
ine that  each  layer  represents  a  year's  work  of  the  flooded  river.  The  fat 
layers  were  thrown  down  in  the  winter  impartially  over  every  poi-tion  of  the 
lake  bottom,  and  with  the  breaking  up  of  the  ice  in  spring  the  flood  swept 
it  off  those  portions  where  it  had  strong  current,  at  times  just  crumpling 
it,  as  shown  in  figs.  39  and  40,  p.  647,  but  over  the  deep  lake  bottom  only 
rippling  its  surface,  the  fat  tenacious  clay  resisting  erosion  slightly,  while  the 
coarse  material  brought  in  by  the  tributaries  was  pushed  in  sheets  out  over 
the  delta  flats  and  dumped  over  their  fronts,  and  in  small  quantity  carried 
out  over  the  clays.  In  exceptional  floods  thin  films  of  these  sands  were 
carried  down  across  the  very  middle  of  the  lake,  as  at  the  Hadley  locality, 
and  came  at  the  beginning  of  the  spring,  for  the  coarse  sand  rests  directly 
in  rippled  hollows  of  the  surface  of  the  finest  clay.  In  this  sand  are  found 
the  twigs  and  reeds  and  leaves  brought  down  by  the  tributaries,  and  the 


TUE  STKUOTUKE  OF  THE  CLAY.  707 

sands  fjrado  up'vard  into  the  lean  portion  of  tlie  layer,  whicli  represents 
tilt'  uuifonu  high  water  of  the  glacial  river  during  the  summer  and  which 
is  a  true  "o-letchermilch,"  and  this  in  its  turn  grades  vipward  into  the  fat 
deposits  produced  by  the  clarifying  of  the  waters  during  the  succeeding 
winter.  This  would  conspire  with  the  fact  that  the  mass  of  the  coarse 
material  of  these  deposits  has  been  brought  in  from  the  sides  and  moved  but 
little  downstream,  to  indicate  a  low  pitch  for  the  valley  during  the  time  of 
the  glacial  stream. 

THE  TIME  OCCUPIED  IN  THE  DEPOSITION  OF  THE  CLAYS. 

The  considerations  of  the  preceding  section  afford  data  for  a  calcula- 
tion of  the  time  occupied  by  the  deposition  of  the  clays,  which  is  presented 
as  interesting  rather  than  specially  valuable.  If  we  take  the  clays  exposed 
in  the  south  of  the  Camp  Meeting  cutting  and  in  the  river  bank  adjacent,  a 
thickness  of  72  feet  is  exposed  down  to  the  water  level,  which  would  give, 
at  an  average  of  two-fifths  of  an  inch  per  layer,  2,155  years.  If  we  take 
the  boring  at  the  Northampton  bridge,  113  feet,  we  have  3,390  years.  As 
these  two  neighboring  sections  are  measured,  the  one  up  and  the  other  down, 
from  the  river  level,  we  may  add  these  two  numbers  to  obtain  a  maximum 
time  for  the  deposition  of  the  clays — 5,545  years.  The  erosion  of  the  Deer- 
field  and  Westfield  basins  and  the  wearing  back  of  Turners  Falls  in  the 
red  sandstone  a  distance  of  3  miles,  with  a  width  of  about  60  rods  and  a 
depth  of  about  40  feet,  and  of  South  Hadley  Falls  in  the  same  sandstone 
for  a  mile,  with  somewhat  greater  width  and  depth,  will  each  give  a  measure 
of  the  time  that  has  elapsed  since. 

ACTION  OF  ICEBERGS  OR  FLOES  UPON  THE  CLAYS. 

Contorted  clays. — At  a  railroad  cutting  just  west  of  the  South  Street 
bridge  in  Northampton,  already  noted  (p.  541)  as  showing  sandstone  and 
till  planed  down  together  into  a  drumlin,  the  clays  rest  normally  on  both, 
and  a  short  distance  eastward  there  begins  a  peculiar  distorting,  crump- 
ling, and  comminuting  of  the  latter.  At  its  worst  the  clays  are  thoroughly 
chopped  up  into  small  pieces,  which  are  mingled  in  entire  confusion. 
This  was  exposed  for  a  distance  of  about  33  feet,  with  a  thickness  of  2  feet. 
Eastward  about  50  feet,  across  a  space  where  the  exposure  was  only 
sufficient  to  show  that  the  clays  were  continuous  and  much  disturbed,  the}' 


708  GEOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 

were  again  well  exposed  in  a  fresh  cutting-,  and  here  the  clay  is  kneaded 
into  fantastic  shapes,  squeezed  into  holes  in  the  drift  below,  and  a  large 
mass  of  coarse,  reddish  drift  has  been  dumped  into  it,  and  the  two  are  in 
places  well  molded  together.  Twenty  feet  farther  on  the  clays  were  per- 
fectly normal  and  horizontal.  The  intervening  space  was  well  exposed,  and 
one  could  see  how  the  clay  disentangled  itself  from  the  mass  of  coarse 
material  and  gradually  reassumed  its  horizontal  lamination.  Below  and 
above  the  disturbed  portion  the  clays  are  quite  horizontal  and  undisturbed. 

This  locality  is  at  the  base  of  a  promontory  in  the  ancient  lake,  around 
which  the  thread  of  the  current  bent  as  it  swept  southwestward  over  East- 
hampton;  and  the  ice  floes  from  the  north,  stranding  here,  have  plowed  up 
the  clays  and  mingled  them  with  the  coarse  material  with  which  they  were 
themselves  loaded. 

In  the  curve  by  which  the  current  bent  around  the  projecting  drumlins 
in  Northampton  several  similar  disturbed  patches  isolated  in  the  otherwise 
horizontal  clays  h?,ve  been  exposed,  as  in  the  digging  of  the  sewer  at  the 
south  end  of  King  street,  where  they  were  so  distorted  that  they  were 
mistaken  for  till  by  a  good  observer.  They  were  described  as  being  thor- 
oughly puddled.  A  mile  farther  northwest,  at  the  great  cut  on  the  railroad 
to  Williamsburg  extending  from  the  Bay  State  Brook  east  to  the  crossroads 
north  of  the  railroad,  the  same  thing  is  shown  for  many  rods  in  the  eastern 
portion  of  the  cutting.  The  sands  are  irregularly  disturbed,  and  at  several 
places  discoimected  pockets  of  bowlders  and  glacial  clay  appear,  wholly 
inclosed  in  the  distorted  sands. 

In  the  same  area  of  disturbance  a  mile  farther  southwest,  the  fine 
exposures  in  the  great  clay  pits  south  of  the  Insane  Asylum  are  illustra- 
tions of  the  same  action.  A  horizontal  line  is  marked  for  many  hundred 
feet  in  the  vertical  walls  of  the  excavations  at  the  same  level  with  the  plane 
of  disturbance  farther  north.  Above  this  line  the  clays  are  undisturbed  and 
about  12  feet  thick  before  they  merge  into  sand;  below  they  are  kneaded 
into  the  most  tortuous  forms,  and  at  times  all  trace  of  structure  is  gone. 
As  in  the  block  above  the  watch  seen  in  the  accompanying  plate  (XIX), 
traces  of  more  than  one  passage  of  the  ice  are  manifest,  and  in  the  largest  of 
the  blocks  shown  in  the  figure  the  extreme  convolution  of  the  plastic  layers 
on  the  one  side,  and  the  faulting  and  incipient  slaty  cleavage  on  the  other, 
are  well  shown.     The  convoluted  layer  in  the  block  to  the  right  is  com- 


SECONDAltY  STRUCTUEES  IN  THE  CLAYS.  709 

pressed  to  one-fifth  of  its  former  leng-th.  Going-  northwest,  we  soon  come, 
at  Sunset  Hill,  on  the  great  drumlins  that  formed  the  shore  of  the  ancient 
lake,  and  it  is  clear  that  the  disturbance  could  not  have  been  caused  by 
ice  coming  down  the  valley  of  Mill  River,  which  lies  behind  these. 

SECONDARY  STRUCTURES  IN  THE  CLAYS. 

Joints. — Where  the  clay  stands  in  vertical  walls  in  the  river  banks  it 
is  in  time  rudely .  fissured  parallel  and  at  right  angles  to  the  exposed  sur- 
face, and  as  the  horizontal  seams  of  sand  weaken  the  cohesion  of  the  mass 
in  the  third  plane  the  river  in  the  spring  flood  often  moves  off  bodily  great 
cubical  masses  of  the  clay  and  heaps  them  up  lower  down.  Several  years 
ago,  on  visiting  the  bank  of  the  river  below  Hadley,  I  found  a  broad, 
horizontal  surface  thus  exposed  at  about  low-water  level,  which  was  jointed 
with  extreme  regularity  and  beauty.  The  principal  lines  ran  parallel  to  the 
edge  of  the  bank,  perfectly  straight  and  parallel  to  each  other  and  an  inch 
apart. 

The  second  set,  also  parallel  to  each  other,  were  an  inch  and  a  half 
apart,  and  made  an  angle  of  60°  with  the  first  set.  The  lines  of  the  second 
set  were  not  always  continuous,  sometimes  failing  between  two  contiguous 
lines  of  the  first  set,  but  continued  beyond  in  the  same  direction.  These 
lines  represented  fissures  which  extended  tloi'ough  one  layer  of  the  clay 
one-third  of  an  inch  thick,  dividing  the  clay  into  blocks  of  mathematical 
regularity.  Toward  the  edge  the  blocks  had  been  moved  by  the  current  a 
short  distance  from  their  original  position,  manifestly  very  soon  after  the 
superincumbent  block  of  clay  had  been  lifted  oii,  for  they  were,  when  I 
examined  them,  so  soft  that  they  could  not  be  touched  without  destroying 
their  form,  and  yet  as  they  lay  they  retained  their  perfect  regulai'ity.  One 
could  not  help  thinking  that  in  olden  time  it  would  have  been  called  a 
fairies'  pavement,  as  still  in  Scotland  the  claystones  are  called  fairy  stones. 

Below,  where  the  large  massses  of  clay  had  lodged,  I  found  the  small 
blocks  piled  in  considerable  abundance,  but  all  softened  and  fused  together, 
and  in  subsequent  years  I  have  always  found  them  in  abundance  under  the 
same  circumstances.  Later  I  found  the  same  jointing  in  the  large  clay  pit 
at  the  Bay  State  in  Northampton,  where  surfaces  3  and  4  feet  square  were 
regularly  jointed,  exactly  as  on  the  river  bank.  When  a  vertical  surface 
had  been  left  for  some  time  and  the  workmen  then  attacked  that  portion  of 


710  GEOLOGY  OP  OLD  HAMPSHIRE  COUNTY,  MASS. 

the  pit  again,  the  large  blocks  of  clay  when  dislodged  would  slip  apart 
easily  along  the  j^lanes  of  bedding,  where  the  films  of  sand  lessened  the 
cohesion,  and  expose  broad  surfaces  of  the  tessellated  pavement. 

It  was  very  plain  that  the  greater  ease  with  which  the  moisture  could 
escape  along  these  sand  layers  was  the  determining  cause  of  the  appearance 
of  the  structure  along  these  planes.  The  moisture  escaped  so  gradually  and 
the  clay  was  so  nearly  homogenous  that  the  shrinkage  tension  could  distri- 
bute itself  equally  throughout  the  mass  and  finally  relieve  itself  by  a  system 
of  fissures  at  angles  of  60°  and  120°,  of  great  mathematical  regularity. 

President  Hitchcock  mentions^  three  localities,  one  on  the  Agawam  and 
two  near  the  Deerfield  Eiver,  where  these  joints  also  occurred  in  the  same 
clays,  and  considers  them  to  be  due  to  a  crystallization  of  the  clay  and  "to 
be  a  more  simple  operation  of  the  same  general  cause  which  produced  the 
concretions." 

In  an  elaborate  paper  entitled  "On  the  structure  of  rocks  called  joint- 
ing,"^ Prof  W.  King  says: 

Hitchcock  states  that  "  unconsolidated  clay  beds  in  West  Springfield  and  Deer- 
field,  in  Massachusetts,  are  intersected  by  numerous  and  distinct  joints,  while  those 
above  and  below  are  unaffected.  This  clay  has  certainly  never  been  subjected  to  any 
great  degree  of  heat,  being  of  very  recent  origin.'"  It  is  to  be  apprehended  that 
there  is  some  oversight  in  this  statement. 

This  seems  to  be  a  wholly  groundless  assumption  on  the  part  of  the 
author,  made  in  support  of  the  theory  advanced  in  the  paper  cited.  I  may 
add  that  the  fissures  extend  vertically  downward  through  the  fat  laminae  as 
if  cut  with  a  knife,  and  pass  down  through  the  sandy  laminje  with  a  curved 
surface. 

The  torsion  theory  of  Daubrc^e  will  hardly  apply,  as  the  joints  are 
found  in  limited  areas  having  relation  to  recent  erosions,  or  in  bluffs  pro- 
duced by  digging.  I  have  searched  the  clays  for  many  years  for  fossils 
and  concretions,  and  these  joints  have  been  wanting  in  so  great  a  number 
of  cases  where  all  the  conditions  were  favorable  that  they  can  not  well  be 
referred  to  any  such  general  cause.  All  the  cases  occurred  in  bluffs  where 
the  wall  below  was  strong  and  well  supported  and  there  would  seem  to 

1  Geology  of  Massachusetts,  1841,  p.  418. 

^Trans.  Royal  Irish  Acad.,  Dublin,  vol.  25,  p.  606. 

'  Elementary  Geology,  p.  22. 


CONCEETIONS.  711 

be  small  place  for  any  iuflueuce  of  torsion.  Yet  from  the  removal  of  the 
clay  to  produce  the  bluff,  and  from  the  quite  sudden  drying  of  the  surface 
i)f  the  bluff,  there  might  be  a  slight  creeping  of  the  clays  still  below  the 
level  of  the  streams,  or  the  wet  floor  of  the  clay  pit  might  produce  torsion, 
which  would  be  influential  in  producing  the  forms  observed. 

Concretions. — In  the  Journal  Book  of  the  Royal  Society  for  1734  is  a 
manuscript  catalogue  of  objects  of  natural  history  found  in  New  England, 
by  John  Winthrop,  magistrate  of  the  Connecticut  colony  and  great-grandson 
of  the  first  governor  of  Massachusetts.  It  mentions  "clay  generated  in  the 
form  of  horse  shoes  from  the  bottom  of  Connecticut  River."  ^  It  would 
be  difficult  to  find  a  boy  brought  up  near  the  Connecticut  who  had  not  in 
the  early  summer  gathered  claystones  on  the  bank  of  the  river  which  had 
been  washed  out  of  the  clay  in  the  spring  floods,  and  wondered  at  their 
abundance,  their  smooth  and  apparently  artificial  surface,  and  their  regular 
form — spherical,  spheroidal,  ellipsoidal,  or  flattened  into  disks,  sometimes 
variously  elongated,  lobed,  or  grotesquely  imitating  animals  and  works  of 
art.  And  he  would  be  hardly  satisfied  with  the  common  explanation  that 
they  were  formed  from  hardened  pieces  of  clay  by  the  wearing  of  the 
water.  This  was  Dr.  Hitchcock's  first  opinion,  and  in  1823^  he  gave  a  full 
mineralogical  description  of  them.  They  thus  very  early  attracted  the 
attention  of  the  geologist,  and  in  1835  President  Hitchcock  describes  them 
with  care,  and  asks  the  questions  :  "But  are  concretions  the  resiilt  of  crys- 
tallographic  laws?  If  so,  why  are  not  crystals  produced?"  The  tubular 
feiTuginous  form  he  describes  as  a  fossil  of  uncertain  character.^  In  the 
report  of  1841  he  devotes  16  pages  and  5  plates  to  a  discussion  of  concre- 
tions, and  presents  a  classification  of  them  according  to  form;  and  though 
he  no  longer  looks  upon  any  of  them  as  fossils,  he  considers  them  exceed- 
ingly difficult  of  explanation  and  thinks  one  must  assume  them  to  be  the 
result  of  the  action  of  galvanic  electricity,  and  associates  with  them,  as  a 
result  of  the  same  general  causes,  the  prismatic  blocks  of  clay  produced 
by  shrinkage  joints  which  I  have  described  on  page  709. 

President  Hitchcock  returns  to  the  subject  in  1861,  in  the  report  on 
the   Geology  of  Vermont,  and  devotes  8  pages  and   3   plates  to   clay- 

1  Am.  Jour.  Sci.,  1st  series,  Vol.  XLVII,  p.  282. 

2 Geology  of  the  Connecticut  River:  Am.  Jour.  Sci.,  1st  series,  Vol.  VI,  1823,  p.  229. 

3Geol.  Mass.,  p.  182. 


712  GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

stones,  and  still  expects  someone  to  develop  the  fundamental  principles  of 
their  formation  and  "do  for  them  what  Abb^  Hauy  did  for  crystallography." 
He  quotes  several  pages  from  Prof.  C.  B.  Adams's  second  report  of  the 
Geology  of  Vermont  on  the  same  subject,  among  other  tilings:  "It  is 
obvious  that  the  description  and  theory  of  concretions  constitute  a  subject 
which,  although  j)erhaps  less  extensive  than  crystallography,  is  as  properly 
entitled  to  rank  as  a  distinct  science."  He  quotes,  also,  from  Professor 
Adams,  a  new  classification  of  these  forms,  much  more  complex  than  his  own, 
and  containing  several  Greek  words  newly  coined  for  the  purpose.  These 
elaborate  classifications  seem  worthless,  and  remind  one  of  Rafinesque's 
paper  describing  and  naming  nine  new  species  of  thunder  and  lightning,  for 
all  the  variety  in  the  forms  depends  solely  upon  causes  wholly  external  to 
the  concretion  itself,  namely,  to  the  constantly  varying  permeability  of  the 
clay  in  its  different  parts  and  the  decomposition  of  its  constituents.  In 
tracing  the  history  of  these  forms  one  must  notice,  first,  that  the  clay  beds 
in  which  they  occur  differ  materially  from  those  beds  of  clay  formed  by 
the  decomposition  of  massive  feldspar  in  situ,  which  are  often  quite  pure 
kaolin — a  hydrated  silicate  of  alumina.  These  Champlain  clays,  on  the 
contrary,  contain  only  a  small  portion  of  true  kaolin,  and  are,  in  the  main, 
an  exceedingly  fine,  largely  feldspathic  sand,  resembling  somewhat  the 
finest  silt  washed  from  a  stamping  mill ;  they  are,  in  fact,  the  finest  portion 
of  the  material  ground  up  by  the  glacier,  and  the  waters  which  bore  it 
southward  may  have  been  in  part  a  veritable  gletchermilch,  issuing  directly 
from  beneath  the  ice.  It  may  have  been  carried  a  long  way  southward  in 
the  valley,  and  thus  have  been  derived  by  the  ice  partly  from  the  Vermont 
rocks,  among  which  limestone  is  prominent. 

It  is  certain,  also,  that  the  clays  contain  abundantly  particles  of  min- 
erals, as  lime  feldspars,  which,  by  their  decomposition,  afford  calcic  carbon- 
ate. And  the  waters  with  which  the  clays  are  saturated  would,  by  virtue 
of  the  carbonic  dioxid  they  contain,  dissolve  and  carry  in  solution  the 
carbonate  derived  from  one  or  both  these  sources.  The  waters  are  con- 
stantly percolating,  with  a  slow,  capillary  motion,  through  the  clays, 
especially  after  the  beds  have  been  cut  through  here  and  there  by  streams 
and  the  edges  of  the  laminae  have  been  exposed,  moving  always  from  the 
moister  toward  the  drier  portions;  and  as  the  conditions  in  this  respect 
often  change,  the  direction  of  their  motion  woixld  also  change. 


CONORETIOiSrS.  713 

Aji'ain,  since,  as  I  have  described  above,  every  layer  is,  as  a  rule, 
cai)ix'<l  b\-  a  thill  lainiiia  much  finer  aud  more  impervious  than  the  rest, 
wliile  the  seams  between  the  laminae  are  often  quite  coarse  sand,  at  least  at 
base,  the  water  would  move  most  freely  in  the  lower  and  coarser  portion 
of  the  hiyer,  and  least  freely  in  the  finer  clay  laminae  above  and  below. 
This  would  tend  to  confine  the  water  within  the  limits  of  single  layers. 
Its  motion  would  vary,  also,  by  infinitesimal  gradations  with  every  varia- 
tion in  the  permeability  of  the  layer  through  which  it  was  passing  and 
with  every  difterence  in  the  force  by  which  it  was  moved. 

If  we  suppose,  now,  that  from  any  cause  a  precipitation  of  the  calcic 
carbonate  is  commenced  at  a  given  point  or  in  a  limited  area  within  the 
coarser  layer — a  precipitation,  that  is,  taking  place  in  the  interstices  between 
and  among  the  grains,  cementing  them  together  without  greatly  moving 
them  from  their  places — the  waters  deprived  of  the  carbonate  held  in  solu- 
tion Avould  move  away  and  be  in  turn  replaced  by  other  water,  still  con- 
taining in  minute  quantity  the  same  salt;  or,  by  diffusion,  a  new  portion  of 
the  salt  would  replace  what  had  been  precipitated,  and,  the  same  cause  con- 
tinuing to  act,  there  would  thus  follow  a  continuous  slow  crystallization 
within  the  limits  and  during  the  continuation  of  its  effective  action.  Nor 
would  the  jjrocess  of  necessity  cease  with  the  exhaustion  of  the  supposed 
cause  by  which  it  was  initiated.  As  a  crystal  already  started  grows  in  an 
undersaturated  solution,  the  calcite  already  crystallized  out  among  the 
grains  of  the  clay  would  form  a  group  of  centers  around  which  more  and 
more  new  portions  of  the  same  would  crystallize  until  a  compact  mass  had 
been  formed,  but  little  permeable  to  water,  which  would  then  continue  to 
increase  by  superficial  accretion,  en-^'eloping  in  its  growth  the  fine  sand,  as 
a  fog  spreads  among  the  trees  of  a  forest. 

If  the  above  considerations  be  founded  on  fact,  it  follows  that  we  have 
only  thus  far  to  seek  for  a  cause  which  may  start  the  growth  of  a  concre- 
tion around  a  given  spot  in  the  clay,  its  continued  increase  being  adequately 
explained  by  a  reference  to  the  laws  of  diffusion  and  crystallization.  So 
far  as  all  the  claystones  of  the  valley  are  concerned,  this  initiating  cause 
entirely  eludes  our  observation.  Very  rarely  a  pebble  or  a  few  grains  of 
sand  are  inclosed  wholly  or  partly  by  the  concretion,  but  I  have  never 
seen  one  occupying  the  exact  center,  and  they  do  not  seem  to  have  been 
the  exciting  cause  of  its  growth,  but  rather  seem  to  show  that  a  regular 


714       GEOLOGY  OF  OLD  HAMPSHIEB  COUNTY,  MASS. 

form  was  sometimes  assumed  in  spite  of  a  marked  want  of  homogenousness 
in  the  stratum  in  which  the  growth  took  place. 

In  a  great  number  of  exactly  similar  concretions,  however,  from  other 
localities,  one  finds  as  a  nucleus  some  portion  of  organic  matter — a  fish, 
shell,  or  leaf — whose  shape  determines  the  form  of  the  concretion,  except 
so  far  as  the  same  may  be  influenced  by  the  texture  of  the  bed  in  which  it 
is  formed.  Here  the  organic  matter  inclosed  in  the  bed  of  clay  or  fine 
sand  gradually  surrounds  itself  with  an  atmosphere  of  the  products  of  its 
own  decomposition,  which  slowly  expands  outwardly — in  a  massive  bed 
extending  equally  in  all  directions;  in  a  laminated  one,  most  widely  in  the 
plane  of  lamination — and  among  these  products  of  decomposition  are  some 
which  readily  ^Drecipitate  the  carbonates  when  by  the  ordinary  capillary 
circulation  the  latter  are  brought  within  their  range.  Thus  as  the  waters 
move  to  and  fro  in  the  bed  they  come  from  every  direction  into  the  area 
of  precipitation,  and  a  solid  dependent  for  its  shape  upon  the  contour  of 
this  area  is  formed  around  the  organic  nucleus,  oftentimes  hermetically 
sealing  it  and  arresting  its  further  decomposition;  while,  on  the  other  hand, 
it  can  not  be  doubted  that  many  times  the  organic  matter  which  formed 
the  nucleus  and  determined  the  deposition  was  wholly  dissipated  into  liquid 
or  gaseous  compounds  before  the  process  was  far  advanced. 

Such  a  nucleus,  now  wholly  vanished,  may  have  determined  the 
beginning  of  the  concretions  we  are  discussing,  and  the  fact  that  Presi- 
dent Hitchcock  found  always  a  distinct  residue  of  inflammable  organic 
matter  in  his  analyses  of  claystones  goes  far  to  show  that  such  was  really 
the  case. 

We  can  see  several  sources  from  which  organic  material  may  have 
been,  and  was,  introduced  into  the  clays  during  and  after  their  formation. 
The  country  was  without  doubt  heavily  wooded  before  the  advent  of  the  ice, 
and  all  the  growth  and  surface  soil  were  ground  up  together  in  the  till  from 
which  the  clays  are  derived,  and  afterwards,  while  the  latter  were  forming, 
an  arctic  growth  had  again  overspread  the  hills  and  worms  burrowed  in 
the  lake  bottom,  as  I  shall  show  further  on  (p.  718);  and  finally,  rootlets 
pierce  even  such  unpromising  beds  as  these  to  great  depths — 25  and  30  feet 
in  the  till  of  the  Western  States,  for  instance,  and  similar  instances  are 
given  below.  I  have  found  them  several  feet  deep  in  the  clays,  with  a 
concretionary  accumulation  of  ferric  hydroxid  ah-eady  commenced  around 


CONCRETIONS.  7 1 5 

them.  When  we  consider,  however,  the  extreme  facihty  M-itli  which  calcic 
carbonate  is  brought  into  solution  and  again  precipitated,  it  would  seem  that 
e\-en  a  slighter  cause  might  start  the  growth  of  a  concretion;  the  decompo- 
sition of  a  grain  of  feldspar  setting  free  an  alkali  which  would  appropriate 
the  carbonic  dioxid,  or  even  the  slight  difference  of  specific  heat  of  dif- 
ferent minerals  starting  feeble  thermo-electric  currents  between  different 
grains,  causing  them  to  become  points  around  which  crystallization  would 
commence,  somewhat  as  a  crystalline  precipitate  forms  along  the  scratches 
of  a  beaker  when  it  is  rubbed  with  a  glass  rod. 

By  cutting  down  a  smooth  surface  at  right  angles  to  the  laminae  in  a 
mass  of  the  clay  one  can  sometimes  find  early  stages  in  the  formation  of 
concretions  which  illustrate  what  has  been  said.  There  are  small  spaces 
confined  between  two  layers  of  the  finer  clay,  rudely  spherical  in  outline, 
though  not  shai'ply  defined,  which  cnt  with  somewhat  greater  difficulty 
than  the  clay  around,  are  lighter  in  color,  and  efi^ervesce  abundantly  with 
acid,  while  the  clay  around  shows  but  slight  signs  of  effervescence.  In  this 
case  the  continued  accumulation  of  carbonate  within  the  limits  already 
marked  out  would  produce  the  small  sphere  which  may  be  looked  iipon  as 
the  normal  form.  The  subsequent  growth  would  be  by  additions  to  the 
outside  of  this,  determined  by  the  varying  permeability  of  the  clay,  pro- 
ducing forms  fluted  on  the  edges  where  the  concretion  spread  thi-ough  sev- 
eral layers — the  constrictions  answering  to  the  denser  layers,  the  convex 
projections  to  the  coarser — and  flat  disks  where  the  increase  was  confined 
to  a  single  lamina.  Finally,  the  coalescence  in  various  ways  and  various 
degrees  of  two  or  more  separate  spheres  or  disks  would  form  all  the  variety 
of  compound  and  imitative  forms. 

In  another  case  I  discerned,  on  cutting  across  the  clay,  that  ferric 
hydroxid  had  been  precipitated  in  a  regular  hollow  shell  J™"- thick,  flat 
spheroidal  in  shape,  14°""  in  greatest  diameter;  and  within  and  concentric 
with  the  first  shell  was  a  second,  similar  in  shape  and  thickness,  8"™  iu 
diameter.  Here  the  influence  of  an  atmosphere  of  decomposition  surroiind- 
ing  a  central  body,  which  precipitated  the  iron  salt  as  the  latter  came  from 
all  sides  within  the  sphere,  seems  to  be  more  apparent.  Finally,  the  annu- 
lar claystones — perfect  rings  of  various  sizes  up  to  10  inches — may  be 
explained  in  the  same  way  by  supposing  the  emanation  from  a  decomposing 
center  to  be  confined  within  a  single  layer,  and  thus  to  assume  a  discoid 


716  GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

form,  and  to  precipitate  carbonate  everywhere  along  its  border,  preventing 
its  penetration  inward  toward  the  center.  The  latter  forms  are  not  found 
in  this  region,  but  occur  in  clays  of  the  same  age  and  origin  at  Rutland, 
Vermont. 

The  common  pipestem  concretions — small,  hollow  tubes  made  of  clay 
or  fine  sand  cemented  by  limonite,  about  the  size  of  a  clay  pipestem — which 
stand  verticle  in  the  clay,  are  plainly  due  to  the  passage  of  water  through 
holes  made  by  small  rootlets,  and  the  latter  can  at  times  be  still  found  in  the 
holes.  At  the  Wapping  cutting  (see  p.  695)  I  was  able  to  lift  up  and  bring 
away  broad,  frozen  sheets  of  the  fine  loesslike  sand,  one-half  inch  thick,  from 
30  to  40  feet  below  the  top  of  the  cutting,  which  showed  the  early  stages  of 
this  growth  very  beautifully.  The  wind  had  delicately  sculptured  the  sur- 
face and  left  the  incipient  concretions  projecting  above  the  surface,  as  a  knot 
projects  above  the  surface  of  a  worn  board,  but  of  regular  shape,  like,  very 
large  checker-men,  each  with  a  small,  central  root  hole,  and  each  about  1^ 
inches  in  diameter  and  concentrically  fluted  with  beautiful  regular  grooves, 
between  which  rise  the  deeper  yellow  ridges  where  the  iron  rust  was  con- 
centrated. When  thawed,  the  whole  bed  could  be  blown  ofi"  the  surface  of 
the  board  upon  which  it  had  been  placed  for  preservation. 

These  ferruginous  forms  have  been  produced  by  decomposing  organic 
matters  at  the  surface,  changing  iron  rust  to  ferrous  carbonate,  which  has 
been  carried  down  the  root  holes  and  precipitated  around  them  and  then 
slowly  changed  to  limonite. 

The  simplest  and  commonest  forai  of  the  calcareous  concretions  is  a 
sphere,  like  that  making  the  center  of  the  largest  specimen  shown  in  the 
figure,  Avhich  expands  regularly  to  form  perfect  disks.  (See  PL  XX.) 
That  the  slow  translation  of  the  fluids  in  the  clay  has  to  do  with  the 
growth  is  -indicated  by  the  common  occurrence  of  spectacle-like  forms,  as 
shown  in  the  plate,  where  two  neighboring  disks,  as  they  approximate 
by  growth,  mutually  shield  each  other  and  so  become  connected  only  by 
a  narrow  isthmus.  That  a  foreign  body  may  cause  the  growth,  perhaps 
simply  by  halting  "the  solutions,  is  shown  by  the  fact  that  the  limonite  pipe- 
stem  concretions  become  the  centers  around  which  the  regular  discoid 
calcareous  concretions  have  grown. 

The  folded  concretion  figured  (PI.  XX)  is  most  interesting  as  showing 
that  the  regular  growth  could  take  place  in  the  contorted  clays,  and  this 


U.   S.   QEOUOOICAL  SURVEY 


MONOGRAPH  XXIX       PL.    XX 


CALCAREOUS   CONCRETIONS  WITH   WORM   TRACKS^    IN   THE   CHAMPLAIN   CLAYS;    HADLEY   AND   NORTHAMPTON. 


CONCKETIONS. 


717 


and  the  largest  concretion  figured  show  beautifully  that  they  took  an  exact 
cast  of  the  full  thickness  of  a  layer,  since  they  are  covered  by  raised  undu- 
lating ridges — the  worm  tracks  mentioned  on  page  719. 

In  the  table  below  I  have  given:  (1)  an  average  of  18  analyses  of 
claystones  from  Massachusetts  and  Vermont,  5  from  Geology  of  Massachn- 
setts  (p.  408),  and  13  from  Greology  of  Vermont  (p.  700);  (2)  the  propor- 
tion of  carbonates  to  the  other  constituents;  (3)  excluding  the  carbonates, 
the  remainder,  reckoned  to  100  per  cent;  and  (4)  the  silica,  alumina,  and 
water,  reckoned  to  100  per  cent. 

Analyses  of  claystoties  from  Massachusetts  and  Vermont,  proportion  of  constituents,  etc. 


CaCo: 

MgCo. 

SiOo  . 

A1:0:,. 

Fe,03 

MnOe 

H,0.. 


47.4 
4.3 
19.1 
16.9 
6.1 
1.9 
4.3 


100 


51.7 


}     48.3 


100 


39.6 

35.0 

12.7 

4.0 

8.7 


100 


45.6 
43.6 


10.8 


100 


Column  No.  2  indicates  that  a  little  more  than  half  the  mass  of  the 
claystones  is  made  up  of  carbonates,  and  these  have  been  wholly  or  in  large 
part  infiltrated,  and  this  may  be  true  also  of  much  of  the  iron  and  man- 
ganese. Column  No.  4  would  indicate  that  the  original  clays  in  which  the 
concretions  used  for  analysis  were  formed  were  wholly  kaolin;  indeed,  there 
is  less  silica  and  water  than  is  needed  for  the  formation  of  kaolin ;  which 
does  not  agree  with  the  results  of  examinations  with  the  microscope.  The 
analyses  are  mostly  old,  and,  I  have  no  doubt,  give  the  quantity  of  the 
AI3O3  too  large,  and  that  of  the  SiOg  correspondingly  small. 

Thin  sections  of  the  small,  round  and  obovate  claystones  show  no  trace 
of  a  continuous  calcite  cement  binding-  the  grains  and  needles  of  the  clay 
together,  but  present  a  very  fine  and  uniform  mass  of  needles  and  grains, 
not  in  any  marked  way  distinguishable  from  the  ordinary  clay.  When 
treated  with  acids,  efi"ervescence  appears  from  spots  covering  the  whole  sur- 
face, and  the  decalcified  slide  is  made  up  almost  wholly  of  kaolin  needles, 
mostly  about  0.008  '""long  and  0.002  """^  wide,  quartz  grains  0.003  °""  across, 


718  GEOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 

and  coal  grains  about  0.004  ™"  across.  On  examining'  a  new  slide  carefully 
with  high  powers  the  larger  grains,  which  disappear  with  acid,  are  found  to 
have  cores  of  quartz  and  a  warty  coating  of  calcite. 

FOSSILS    OF    THE   CHAMPLAIN    CLAYS. 
REMAINS   OF   PLANTS. 

So  far  as  I  can  learn,  no  fossils  have  been  described  from  the  clays  of 
the  basin,  nor,  indeed,  from  those  of  the  valley  of  the  Connecticut  above 
and  below.  As  early  as  1852  Dr.  James  Eights  Wrote  as  follows  of  the 
Hudson  River  clays: 

In  one  of  tliose  thin  seams  of  fine  sand  that  separate  the  strata  of  clay,  about 
15  feet  below  the  surface  of  the  soil  [in  a  plain  UGO  feet  above  sea  level],  are  to  be  found 
the  remains  of  a  vegetable  much  resembling  in  appearance  the  leaves  and  stems  of  the 
Mitchella  repens.  .  .  .  These  leaves  have  undergone  but  a  slight  change  in  their 
nature,  still  retaining  all  the  flexibility  of  the  more  recent  plant.' 

These  were  very  probably  leaves  of  Vacciniwn  oxycoccus,  which  are  the 
most  abundant  in  the  clays  of  the  Connecticut. 

In  the  summer  of  1878,  while  on  an  excursion  with  the  senior  class  of 
Amherst  College,  I  detected  a  few  very  small  leaves  in  the  river  bank  below 
Hadley,  at  the  north  end  of  the  clay  exposure,  opposite  the  house  nearest 
the  bridge  over  Fort  River;  and  on  a  similar  excursion  in  1879  I  found  that 
the  floods  of  the  preceding  spring  had  cut  deeply  into  the  clays  at  that  place 
and  piled  great  masses  near  the  south  end  of  the  exposure  above  low-water 
mark.  From  these  blocks  I  obtained  a  better  supply,  though  they  were  far 
from  abundant.  They  were  confined  within  narrow  limits,  both  vertically 
and  horizontally,  and  were  generally  scattered  singly  in  the  laminae.  In  two 
cases  layers  were  separated  containing  twenty  or  more  leaves  of  several 
species  and  preserving  delicately  the  impression  of  both  the  upper  and 
under  surface.  They  were  uniformly  very  small — 10  to  20"'"  in  length — 
generally  thick  and  coriaceous.  From  their  occurring  scattered  singly  in 
the  beds  and  associated  with  ripe  seed  vessels,  I  assume  them  to  have  been 
blown  off  the  land  by  the  autumn  winds ;  and  their  position  at  or  just  above 
the  base  of  the  upper  fine  portion  of  the  layer  confirms  the  supposition 
already  expressed — that  this  fine  portion  was  deposited  in  the  winter. 

During  the  same  year  my  colleague,  Mr.  J.  M.  Clarke,  obtained  leaves 

'  Observations  on  the  geological  features  of  the  post- Tertiary  formation  of  the  city  of  Albany 
and  its  vicinity :  Trans.  Albany  Inst.,  Vol.  II,  p.  346. 


FOSSILS  OF  THE  CHAMPLAUST  OLAYS.  719 

of  the  same  species  from  the  cla}-  baiilc  near  Fort  River  and  east  of  the  Fair 
Grounds  ii\  Amherst.  Here  they  were  matted  together,  leaves  and  twigs, 
in  a  hiyer  several  luilliineters  thick  over  a  small  surface.  Later  I  obtained 
the  same  leaves  in  some  abundance  from  the  clay  beds  at  the  cutting  south 
of  College  Hill,  opposite  the  Central  station,  where  the  clays  rise  to  their 
greatest  height.  I  have  also  found  them  at  the  brick  pits  beyond  the  asylum 
at  Northampton. 

Besides  the  abundant  trails  of  minute  dipterous  larvae,  nine  j)lants 
have  been  identified  with  ai'ctic  and  subarctic  species  by  comparison  with 
White  Slountain  and  arctic  plants  in  the  Amherst  Herbarium;  these  are 
enumerated  below. 

Viola  palustris  L.  Very  small  leaves,  round  heart-shaped,  crenate,  with 
four  principal  veins,  agreeing  well  with  the  smallest  leaves  from  the  White 
Jlountains.  Two  or  three  leaves  at  Hadley.  Several  at  the  Hampshire 
Park  locality,  Amherst. 

Vaccinium  oxycoccus  L. — Leaves  punctate  above,  rolled  up  underneath, 
heart-shaped  posteriorly ;  stem  short  and  broad.  While  they  agree  in  shape 
and  size  closely  with  the  species  to  which  I  have  referred  them,  the  vena- 
tion, which  is  indistinct  in  the  herbanum  specimens  I  have  examined,  is 
well  marked  in  the  fossil  specimens.  I  have  assumed  this  to  be  the  result 
of  maceration  in  the  latter,  since,  so  far  as  I  could  compare  them,  the  vena- 
tion was  alike  in  both.  Twigs  occur  carrying  several  leaves  and  several 
nicely  preserved  seed  vessels.  Very  abundant  both  at  Hadley  and  at 
Hampshire  Park  south  of  College  Hill,  Amherst. 

Vaccinium  uliginosum  L. — Very  rare;  Hadley. 

Rhododendron  lapponicwn  Wahl. — Single  leaves;  referred  with  some 
doubt  to  this  species.     Hadley. 

Arctostaphylos  alpina  Spr. — Several  leaves  agi'eeing  exactly  with  those 
from  the  White  Moimtains.     Hadley. 

Arctostaphylos  uva-ursi  Spr. — Single  leaves;  referred  with  some  doubt 
to  this  species.     Hadley. 

Oxyria  digyna  Campd. — The  single  impression  of  a  small  lenticular 
seed  vessel,  which  agrees  very  closely  with  the  impression  made  by  the 
opened  achenium  of  the  mountain  sorrel.     Hadley. 

Salix  cutleri  Tuck. — Leaves  agreeing  exactly  with  this  species  are 
found  oftener  than  any  other.     They  are  often  folded  together  along  the 


720  GEOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 

midrib,  which  I  found  to  be  the  case  also  in  the  dried  specimens  studied. 
Small  sessile  seed  vessels,  several  on  one  stalk,  also  occur  in  several  cases. 
Hadley,  and  Hampshire  Park,  Amherst. 

Lycopodmm  selago  L. — I  have  referred  to  this  species  a  single  specimen 
agreeing  with  it  in  habit  and  in  shape  of  leaf,  but  much  smaller.  Hamp- 
shire Park,  Amherst, 

In  1835  Dr.  Hitchcock  described  fossils  from  Deerfield,  Greentield,  and 
South  Hadley,  of  a  single  genus  in  an  imperfect  state,  resembling  Ovulites 
margantula  Goldfuss  or  Scyphia,  which  the  full  description  shows  to  have 
been  ferruginous  pipestem  concretions.^ 

BUKROWS   OP   DIPTEEOTJS   LARVAE. 

Over  many  surfaces  of  the  laminse  which  were  free  from  the  delicate 
rippling  I  have  described  above  (p.  703),  and  were  exceptionally  smooth 
and  fine-grained,  run  delicate  raised  threads  in  regular  undulations,  each 
curve  being  4™"  long  and  S""™  deep.  At  times  the  raised  thi-ead  is  replaced 
by  a  groove  of  corresponding  size,  1  to  1^°""  in  width.  These  may  have 
been  formed  by  minute  worms  burrowing  just  below  the  surface  and  raising 
a  ridge,  which  sometimes  sank  in  to  form  the  cori'esponding  groove.  They 
occur  30  to  40™"  in  length.  It  is  also  interesting  that  the  claystones  have 
taken  the  cast  of  the  partings  between  the  clay  layers  so  accurately  that  in 
the  large  disk-shaped  stone  figured  in  PI.  XX,  p.  716,  both  sides  are  covered 
by  the  grooves  and  ridges,  and  these  show  distinctly  in  the  photograph. 
The  claystone  came  from  a  point  30  feet  below  the  level  of  the  Connecticut 
at  the  west  pier  of  the  railroad  bridge.  The  same  trails  appear  abundantly 
on  the  surface  of  the  folded  claystone  figured  on  the  same  plate;  the  exact 
localit}^  from  which  this  stone  came  is  not  known,  but  it  is  probably  in 
Northampton  or  Hatfield.  These  tracks  were  first  figured  by  Hogbom* 
from  interglacial  clays  in  Jemtland,  Sweden.  They  were  later  described 
by  Dr.  Gunnar  Anderson^  from  Jemtland  and  Finland.  They  were  iden- 
tified by  him  with  the  traces  made  by  the  larva  of  the  dipterous  insect 
Chironomus  motilator. 

These  traces  have  been  found  from  the  strandzone  to  300  fathoms  in 
depth,  in  salt  and  fresh  water,  and  in  both  temperate  and  arctic  climates.* 

■  Geology  of  Massaeliusetts,  p.  182. 

2  Geol.  Fijreningens  Stockholm  Forliandl.,  Vol.  XV,  1893,  p.  29. 
"  Sveriges  Geol.  Undersiikning,  Series  C,  No.  166,  1897,  p.  22  (60). 

•Tr.  Meinert,  De  eucephale  Myggelarver:  KjiibenUavu.  Vidensk.  Selsk.  Skrifter,  6  Eaekke,  Vol. 
Ill,  4,  1886,  pp.  441-444. 


FOSSIL  LEAVES. 


721 


REMAINS    OF   FISHES. 


Fig. 46 Pharyngeal  bone  of  aflsh,  from 

the  Champlain  clay,  Holyoke. 


In  18i)o  otie  of  my  class  t'ouud  half  of  the  pharyngeal  bone  of  a  fish 
in  the  Champlain  clay  20  rods  above  the  old 
oxbow  of  the  Fort  Kiver  beloAV  Hadley  street. 
It  was  given  to  me  on  the  spot  and  was  lost  by  me 
through  excess  of  care.  It  was  about  an  inch  long, 
and  the  principal  peculiarity  was  that  the  teeth, 
which  were  rounded  and  slightly  bent  cones  about  the  size  and  proportion 
of  a  rather  long  lead-pencil  point,  were  in  a  double  row,  pointing  outward. 
The  outer  surface  below  the  teeth  curved  outward  and  was  quite  deeply 
excavated  vertically  in  several  grooves,  so  that  the  rounded  ridges,  radiat- 
ing a  little,  resembled  the  base  of  a  tree  trunk.  The  annexed  cut,  drawn 
from  memory  soon  after  the  loss,  represents  the  teeth  quite  accurately, 
thoiigh  making  them  a  little  too  large  for  proportion.  Profs.  E.  D.  Cope 
and  Bashford  Dean,  to  whom  I  submitted  my  di-awing,  agreed  that  it  was 
the  pharyngeal  bone  of  a  carniverous  dacehke  fish  near  Leuciscus  or  Rhodus. 

MON  XXIX —  46 


CHAPTER    XXT. 
TERRACES  AND   MODERN   DEPOSITS. 

INTRODUCTION. 

An  inspection  of  the  profile  of  the  river  (PI.  XXI)  shows  in  a  striking 
way  the  ineffectiveness  of  the  stream  at  low  water  and  its  effectiveness  at  high 
water.  At  low  water  it  enters  the  State  181  feet  above  sea  level  and  leaves  it 
39  feet  above,  but  of  this  descent  of  142  feet  a  fall  of  132  is  expended  at  the 
two  dams  and  the  French  King  Rapids,  and  10  feet  only  in  the  intermediate 
spaces,  less  than  2  inches  to  the  mile,  as  this  portion  of  the  river  is  about 
70  miles  long.  At  high  water  it  crosses  the  State  line  at  218  feet^  above 
sea  level  and  leaves  the  State  57  feet  above  sea  level,  a  difference  of  161 
feet,  and  of  this  only  83  feet  is  lost  at  its  falls  and  rapids;  78  feet  is  divided 
over  the  long  stretches  of  the  stream,  a  little  less  than  14  inches  to  the  mile 
on  an  average,  though  in  reahty  the  stream  is  divided  into  segments  having 
velocities  which  oscillate  widely  about  this  mean. 

This  is  the  time  of  active  work  for  the  flooded  stream,  and  much  work 
o'oes  on  beneath  its  turbid  waters,  which  is  immediately  visible  when  these 
waters  subside,  and  much  which  has  been  unsuspected  and  which  is  not 
readily  recognized.  The  visible  effects  are  the  erosion  of  its  banks,  the 
increase  of  its  bars,  and  the  spreading  of  a  fine  loam  layer  over  its  flood 
plain.  The  invisible  work  is  the  scouring  out  of  the  channel  and  the  trans- 
portation through  it  of  an  unknown  mass  of  sands,  and  then  the  building  up 
of  the  old  bars  and  shallows  again  in  the  old  places  so  perfectly  that  one 
does  not  suspect  that  they  have  been  removed  at  all. 


1  This  hi^li-water  datum  was  taken  from  the  Northfleld  ferry  house.  The  following  notices  of 
years  of  especially  high  water  are  taken  from  the  Supplement  of  the  Hampshire  Gazette,  November, 
1895:  "1801,  great  flood  of  Connecticut  Eiver,  called  '  Jefferson  flood ; '  1843,  Aprill5  to  18,  great  flood ; 
1862,  highest  water  ever  known  in  the  Connecticut,  known  as  the  Lincoln  flood;  all  the  houses  on 
Maple  and  Fruit  streets  submerged." 

722 


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MONOSHAPH  XXIX  PLXXr 

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PROFILE  OF  CONNECTICUT  Rl  VEFf  FROM  HARTFORD. CONN..T0  VERNON,  VERMONT 

»   il    «   1* 

U       <7      «      «      »      H 

THE  TEKKACES  OF  THE  CONNECTICUT.  723 

A  streuiu  teiuls  to  iiuTuase  its  meanderiugs  until  friction  on  bank  and 
bottom  of  its  increased  length  uses  up  all  the  force  derived  from  its  descent 
during  flood  time.  But  when  this  happy  equilibrium  is  reached  the  river 
goes  beyond  it  and  grows  too  long.  It  then,  for  relief,  cuts  off  an  oxbow  in 
a  sluggish  stretch,  as  the  Connecticut  has  often  done  between  Sugar  Loaf 
and  Holyoke.  This  gives  the  section  of  the  stream  new  life  and  eroding- 
power  by  as  nuTch  as  it  is  shortened;  and  hence,  since  the  great  oxbow  was 
cut  off  at  the  Northampton  Meadow  there  has  been  more  complaint  of  the 
loss  of  land  by  erosion  across  the  Hadley  and  Northampton  meadows  than 
anywhere  else  on  the  river.  The  erosion  has  been  especially  severe  at  the 
upper  and  lower  ends  of  Hadley  street,  and  the  location  of  the  two  bridges 
at  Northampton  has  done  much  to  direct  and  deflect  the  stream,  especially 
promoting  the  erosion  above  those  bridges  on  the  east  side  and  the  growth 
of  the  islands  on  the  west.  At  the  extreme  western  apex  of  the  great  bend 
the  stream  has  worn  into  a  hill  of  coarse  di-ift,  out  of  which  it  has  con- 
structed a  natural  riprap,  which  is  restored  as  often  as  broken,  and  a  period 
is  put  to  the  stream's  wear  in  that  direction,  so  that  everything  points  to  its 
cutting  across  parallel  to  Hadley  street  unless  careful  precautions  are  taken — 
more  careful,  it  seems  to  me,  than  have  been  thought  necessary. 

By  the  continued  work  of  the  agents  here  briefly  mentioned,  some  of 
which  are  more  fully  discussed  in  the  section  on  incomplete  terraces  (p.  731), 
the  Connecticut  has  swung  to  and  fro  across  the  abandoned  lake  bottom  as 
a  cable  swings  through  the  water.  The  sands  have  melted  away  before  it 
and  filled  in  behind  it,  holding  it  to  a  constant  width.  In  the  Springfield 
Lake  it  has  cut  down  very  deeply  into  the  lake  sands,  especially  below 
Holyoke,  forming  many  and  complicated  teiTaces. 

In  the  Hadley  Lake  it  has  lowered  only  very  little  since  it  began  to 
flow  as  a  river,  forming  few  and  broad  terraces.  At  the  Northampton  bridge 
the  track  runs  off  the  bridge  at  the  west  end  and  cuts  the  lake  bottom,  and 
from  the  east  end  one  looks  down  on  the  lowest  complete  terrace,  less  than 
20  feet  below  the  level  of  the  bridge.  In  the  Montague  Lake  the  downward 
erosion  was  arrested  by  the  waters  striking  the  Lily  Pond  sandstone  reef, 
in  Gill,  and  after  they  had  rounded  this  reef  they  cut  down  rapidly  to 
present  level,  forming  an  extra  terrace  not  marked  farther  south. 


724  GEOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 

THE  INTERMEDIATE  TERRACE  AKD  THE  BARRIER  AT  THE   lilLX 
POND   IN  GIEL,  AN  ABANDONED  WATERFAXL. 

Mr.  Warren  Upham,  in  his  Survey  of  the  Terraces  of  the  Connecticut 
River  in  New  Hampshire/  described  a  "second  apparently  connected  series 
of  terraces  which  mark  one  of  the  principal  flood  plains  formed  by  the 
river  during-  its  work  of  erosion."  It  is  "most  clearly  continuous  below 
the  south  line  of  Brattleboro,  but  seems  to  be  traceable  from  White  River 
Falls." 

In  the  center  of  the  State  I  was  not  able  to  trace  any  well-marked 
series  corresponding  with  that  described  by  Mr.  Upham,  but  commencing 
at  the  north  line  it  runs  down  the  river,  well  marked  and  continuous,  to 
the  beginning  of  the  canyon  below  Northfield  Farms,  and  it  had  long  been 
a  problem  to  me  why  the  terrace  so  broadly  worn  into  the  older  sands  in 
•the  north  was  so  faintly  represented  farther  south. 

A  study  of  the  sandstone  ridge  at  the  Lily  Pond^  quarry  of  Triassic 
"bird  tracks"  in  the  summer  of  1882  made  it  clear  to  me  that  here  had  been 
the  site  of  a  waterfall  of  the  Connecticut  which  had  worn  back  two  short 
canyons- about  100  feet  long,  in  the  northern  and  deepest  of  which  the  Lily 
Pond  lies,  and  that  the  two  had  included  a  rocky  island  between  them,  just 
as  is  the  case  at  present  with  Turners  Falls,  and  on  a  larger  scale  with 
Niagara.  This  held  up  the  waters  to  the  level  of  the  300-foot  terrace 
above  this  point. 

After  an  amount  of  erosion  which  must  have  represented  a  considerable 
lapse  of  time,  the  stream,  wearing  into  the  sands  of  the  great  delta  on  the 
south,  cut  round  the  edge  of  the  ridge  to  the  left  and  sunk  suddenly  to 
nearly  its  present  level,  abandoning  (a)  its  course  through  the  Lily  Pond 
and  Bartons  Cove,  and  (b)  the  other  branch  starting  from  the  other  notch  in 
the  ridge  and  running  parallel  with  the  first,  and,  like  it,  still  represented  by 
a  "cove"  extending  back  some  distance  along  the  abandoned  channel.  The 
river  took  thus  a  more  circuitous  course  through  the  "  narrows,"  and  had 
still  to  cut  down  somewhat  to  reach  its  present  level,  as  the  prolongation  of 
the  sandstone  ridge  appears  just  above  the  water  level  on  the  other  side 
of  the  stream,  coming  out  from  under  the  thick  delta  sands.  This  is  doubtless 
the  reason  why  the  width  of  the  stream  is  so  small  at  this  point. 

'  Geology  of  New  Hampshire,  Hitchcock,  Vol.  Ill,  p.  58. 

=  This  is  the  third  Lily  Pond  mentioned  in  this  chapter;  one  is  in  South  Vernon,  Vermont,  the 
other  in  West  Northfield,  and  this  is  just  east  of  the  Factory  village,  in  the  town  of  Gill. 


THE  TERRACES  OF  THE  CONNECTICUT.  725 

The  n'k'w  o-ivuu  in  ]*1.  XXII  is  taken  from  the  edg-e  of  the  high  ter- 
race ii  mile  north  of  Willis  Hill,  in  Montague,  looking-  north  across  the  Con- 
necticut dm-ing-  the  spring  flood.  The  stretch  of  the  river  between  the 
"narrows"  and  the  "horserace"  is  double  the  usual  width,  and  it  extends 
south  covering  the  broad  flats  shown  on  the  map.  The  broad  notch  (a  b) 
in  tlie  sandstone  ridge  to  the  north,  across  the  river,  is  the  notch  by  whicli 
the  waters  formerly  passed  to  fall  deeply  into  the  canyon  concealed  to  the 
north.  The  small  southward  projection  on  the  map,  of  the  crescent-shaped 
pond,  which  is  the  Lily  Pond,  represents  this  canyon.  The  contours  on 
the  map  are  here  incorrect,  for  the  ground  rises  along  the  ridge  to  the  east. 
The  second  notch  (c)  is  opposite  the  next  pond  to  the  left;  the  place  where 
the  river  turned  the  obstacle  (d)  and  cut  down  to  the  point  of  the  sand- 
stone ridge  is  the  narrows  on  the  map. 

THE    LOW-LEVEL    TERRACES    AND    FLOOD  PLAIN"  OF  THE   CONNECT- 
ICUT   IN  THE  BASIN  OF  THE  MONTAGUE   LAKE. 

The  subsidence  of  the  waters  of  the  Connecticut  lakes  to  the  present 
Connecticut  River  was  very  rapid,  interrupted  above  the  Lily  Pond  falls 
during  their  existence  (see  PL  XXII), '  but  completed  perhaps  still  more 
suddenly  here  by  the  turning  of  the  Lily  Pond  reef  by  the  waters,  as 
described  on  the  preceding  page. 

As  a  result,  one  goes  down — through  the  whole  length  of  the  Mon- 
tague Lake,  which  was  well  filled  up  in  the  flood  time,  except  in  its  southern 
portion — ^by  a  great  scarp  to  the  series  of  erosion  terraces  of  the  modern 
river,  the  highest  of  which  rise  but  a  few  feet  above  the  level  of  the  flood 
plain.  I  have  colored  these  on  the  map  with  diff"erent  shades  of  yellow 
the  darkest  for  the  highest  and  oldest  terrace,  farthest  from  the  river  (t*), 
the  lightest  shade  but  one  for  the  present  flood  plain  (t^),  and  a  very  light 
yellow  for  well-marked  but  incomplete  terraces  below  the  completed  flood 
plain  (t*).  Abandoned  oxbows  (o  x)  and  old  river  courses  (o  b)  now  play 
an  important  part  and  are  colored  by  lines  of  the  same  shade  as  the  terrace 
coeval  with  them.- 

These  later  terraces  form  the  "meadows"  of  the  Connecticut.  The 
Northfield  Meadows  and  the  romantic  recess  opposite,  and  the  beautiful 
Pine  Meadow  above  Northfield  Farms,  are  the  only  ones  of  considerable 
extent  carved  in  the   northern   lake,  for  from  the  latter  place  the  river 


726 


GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 


any  evidence  of  an  intermediate  water  stand,  the  rapidity  of  the  decHne  of 
flows  between  rocky  banks  to  the  mouth  of  the  Deerfield  River  and  is 
bordered  only  by  narrow  terraces  until  it  reaches  the  Hadley  Lake  basin 
at  Sunderland. 

THE  LATER  TERRACES  OR  MEADOWS  OF  THE  CONNECTICUT*  IN  THE 

HADLEY  LAKE. 

The  Sunderland,  Hatfield,  Hadley,  and  Northampton  meadows,  the 
most  famous  farming-  lands  and  the  earliest-settled  portion  of  old  Hampshire 


Fig.  47.— Sketch  of  the  point«of  the  Northampton  Meadow  from  Mount  Holyoke,  to  show  that  the  meadow  is  a  composite  of 
many  islands.    Except  when  seen  just  before  sunset,  the  meadow  seems  an  almost  perfect  plain. 

County,  make  up  the  area  built  by  the  Connecticut  since  its  shrinkage 
to  near  its  present  dimensions,  in  its  passage  from  Sugar  Loaf  to  Mount 
Holyoke. 

The  old  lake  bottom  lay  so  low,  especially  in  all  the  area  north  of 
Mount  Warner,  in  Hatfield  and  North  Hadley,  that  after  one  has  followed 
down  the  slope  from  the  high  lake  bench  to  and  across  this  bottom  to  the 
scarp,  a  few  feet  in  height,  above  the  oldest  of  these  later  terraces  (a  scarp 
which  registers  the  farthest  outward  swing  of  the  river),  and  has  failed  to  find 


THE  TEKUAGES  OF  THE  OONNECTICDT.  727 

the  water  to  essentially  its  present  volume  becomes  ([uite  manifest.  The 
niea(U)\vs  are  broad  prairies  of  the  richest  soil,  the  g-ift  of  the  river,  and 
seen  from  Mount  Holyoke  or  Sugar  Loaf  when  the  crops  are  on,  as  they 
are  farmed  without  fenciug,  they  spread  in  a  carpet  of  wonderful  Ijeauty  at 
one's  feet  and  take  their  j)lace  in  a  landscape  which  owes  much  of  its  charm 
to  the  inunediate  proximity  of  the  prairie  and  the  mountain. 

The  plain  that  seems  so  perfectly  level  when  seen  from  above  proves 
on  closer  inspection  to  be  made  up  of  a  series  of  broad,  low  ridges  (fig.  47), 
like  the  long,  low  swell  that  comes  in  on  the  coast  after  a  distant  storm,  and 
the  curved  grooves  which  separate  these  ridges  run  approximately  parallel 
to  the  bank  of  the  stream,  but  with  greater  or  less  curve.  This  is  due  to 
the  composite  nature  of  the  terrace  itself,  as  explained  in  a  general  way 
on  page  722  and  illustrated  in  its  details  in  the  discussion  of  incomplete 
terraces  on  page  731.  Each  of  these  low  bars  represents  one  of  the  ele- 
ments out  of  which  the  terrace  is  built,  and  has  passed  through  the  stages 
of  bar,  island,  and  "  glacis  terrace,"^  as  it  has  a,dded  itself  to  the  previously 
formed  plain,  while  the  groove  on  the  outside  of  each  ridge  (out  from  the 
river)  is  the  unfilled  remnant  of  the  waterway  which  separated  the  island 
from  the  fonner  shore. 

The  surface  of  the  broad  terrace  plain  north  of  North  Hadley  and 
extending  up  to  Sunderland  shows  this  most  strikingly,  and  when  seen 
from  the  hill  just  north  of  Hatfield  each  separate  island  of  whicb  the  ter- 
race was  built  by  the  westward  swing  of  the  river  can  be  picked  out. 

THE  STRUCTURE  OF  THE  TERRACES. 

The  river  sands. — The  two  scarps  which  form  the  riverward  limit  of  the 
old  lake  bottom  and  the  outer  boundary  of  the  terrace  system  on  either  side 
of  the  river,  and  represent  the  outermost  limits  of  the  oscillations  of  the 
stream,  afford  the  best  natural  sections  of  the  lake-bottom  beds  and  com- 
monly expose  at  least  the  upper  portion  of  the  clays  and  their  junction  with 
the  sands  above,  a  junction  very  often  marked  by  a  line  of  springs.  Between 
these  scarps  the  river-bottom  sands  rest  in  the  trough  cut  in  the  clays  by 
the  river,  and  the  stream  rarely  nins  directly  on  the  subjacent  clays.  These 
sands  are  of  medium  grain,  well  washed,  straticulate,  with  southward  dip, 
and  often,  in  addition,  cross  bedded  with  sharp  southward  or  more  moderate 

'  Hitchcock,  Surface  Geology,  1860,  p.  5. 


728       GEOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 


northward,  eastward,  or  westward  dips,  according  to  their  position  upon 
the  bar  of  which  they  form  part. 

The  much  sands. — In  1838  President  Hitchcock  wrote  :^ 

Luther  Eoot,  in  digging  a  well  in  Sunderland,  80  rods  from  Connecticut  Eiver, 
at  bottom  cut  through  a  thick  stratum  of  quicksand  smelling  of  sulphuretted 
hydrogen.  This  sand  proved  to  be  very  fertile.  The  same  happened  from  a  well  in 
South  Deerfield,  on  land  of  Mr.  Eufus  Eice.  The  bed  was  6  feet  from  the  surface. 
On  searching,  the  bed  was  found  on  the  bank  of  the  river  in  Sunderland.  It  is  the 
first  stratum  that  retains  water. 

President  Hitchcock  traced  it  through  the  Connecticut,  Deerfield,  and 
Westfield  river  valleys.  It  is,  when  wet,  slightly  green  and  soapy,  but  is  a 
fine  sand.  It  contains  non  oxide  and  vegetable  fiber,  and  many  analyses 
are  given  showing  "  soluble  and  insoluble  geine"  (as  the  substances  that 
may  be  exti'acted  from  vegetable  mold  were  then  called),  sulphate  and  phos- 
phate of  iron,  and  silica.  In  his  final  report^  he  returns  to  the  subject  at 
great  length,  compares  the  fertilizing  part  to  the  slime  deposit  of  the  river 
and  expects  much  from  its  ixse  upon  lands.  He  calls  it  "  muck  sand,"  but 
notes  that  it  is  commonly  called  quicksand. 

Where  I  have  been  able  to  study  this  it  has  proved  to  be  the  finer 
deposit  thrown  down  in  the  channels  between  islands  and  the  shore  to  which 
they  were  in  process  of  joining  themselves,  which  channels  are  generally 
silted  up  at  the  upstream  ends  first  and  remain  then  long  filled  with  stag- 
nant water.     They  are  called  "intervals"  on  many  New  England  rivers. 

Peat  deposits,  plant  remains. — In  his  first  article  on  the  geology  of  the 
valley^  President  Hitchcock  writes: 

In  the  meadows,  logs,  leaves,  butternuts,  and  walnuts  are  found  undecayed  15 
feet  below  the  surface,  and  stumps  of  trees  have  been  observed  at  that  depth  stand- 
ing yet  firmly  where  they  once  grew.  In  the  same  meadows  a  few  years  since  several 
toads  were  dug  up  from  15  feet  below  the  surface,  and  3  feet  in  gravel,  which  soon 
recovered  from  a  torpid  state  and  hopped  away. 

From  the  plain  east  of  the  south  end  of  Sunderland  street,  beneath  7 
feet  of  sand,  hemlock  logs  with  bark  and  leaves,  beech  nuts,  and  pine  burs, 
have  been  very  frequently  dug  up,  as  reported  to  me  by  Dr.  Trow,  of  that 
town.  These  remains  occur  sparingly  in  the  river  sands  everywhere  as 
water-logged  fragments,  and  more  abundantly  in  old  stream  beds  and  in  the 

'Economic  Geology  of  Massachusetts,  p.  93. 

2  Geology  of  Massachusetts,  1841,  p.  107. 

3  Geology  of  Deerfield :  Am.  Jour.  Soi.,  1st  series,  Vol.  1, 1819,  p.  108 ;  also  Final  Report,  1841,  p.  366. 


THE  TERRACES  OF  THE  CONNECTICUT.  729 

sheltered  o-rooves  descl'ibed  above  in  connection  witli  the  "muck  sand.''  In 
diyfi-ing-  wells  in  tlic  loner  i)art  of  Northampton  along  Maple  street,  on  the 
north  side  of  Mill  River,  and  near  the  road  leading-  to  Hockanuni  Ferry 
from  I'leasant  street,  the  deposit  has  been  found  IG  to  20  feet  below  the 
river — a  line,  bluish  loam,  with  leaves,  branches,  and  roots,  butternuts,  but- 
touballs,  hendock  knots,  and  a  piece  of  coal.  The  same  deposit  was  exposed 
at  the  foot  of  King-  street  in  Northampton. 

Loess. — The  most  important  stratum  which  goes  to  make  up  the  ter- 
races is  the  wholly  unstratified  loess  which  everywhere  caps  thetn.  It  is 
most  impoi-tant  economically  as  giving  the  meadows  their  fertility,  and 
deserves  attention  as  a  true  water-formed  river  loess.  Except  for  the  lack 
of  any  large  per  cent  of  calcic  carbonate,  which,  as  there  is  almost  no  lime- 
stone in  the  drainage  area  of  the  Connecticut,  is  not  surprising,  and  for  the 
resultant  rarity  of  land  shells  in  the  bed,  its  agreement  with  the  Rhine  loess 
is  complete.  It  caps  the  river  sands,  and  up  and  down  the  river  presents 
a  cornice,  often  8  feet  thick,  of  a  fine,  dark,  wholly  unstratified  loam, 
])ierced  full  of  vertical  root  holes  and  breaking  with  vertical  walls.  It  is 
the  accumulated  silt  of  the  annual  floods  of  the  river,  each  layer  being 
worked  over  by  wind  and  frost  and  by  the  boring  of  worms  and  roots 
until  the  whole  becomes  entirely  massive;  and  a  rudely  columnar  structure 
is  produced  by  the  multitude  of  root  holes,  which  become  passages  for 
water  after  the  rotting  of  the  roots,  and  so  lessen  the  cohesion  in  this  direc- 
tion that  a  vertical  cleavage  results.  This  loess  layer  appears  capping  the 
surface  in  the  section  (fig.  48,  p.  737).  It  is  finely  shown  in  the  curving 
bank  above  Northampton  bridge,  where  the  river  is  wearing  with  great 
rapidity  into  the  Hadley  Meadow  and  is  forming  already  a  great  semicircle. 
Here  the  loess  forms  a  perpendicular  wall  below  which  the  sand  slope  is 
cut  into  great  steps  by  the  river  as  it  sinks  from  high  water,  so  that  the 
whole  resembles  a  Roman  circus.  The  loess  is  here  5  feet  thick.  Over  the 
Hatfield  lower  meadow  it  is  6  feet  thick;  over  the  upper  meadow  about  2 J 
feet.  Over  the  Northfield  Meadows  the  loess  is  6  to  8  feet  thick,  and  is 
especially  strongly  developed  in  the  West  Northfield  Meadows. 

THE  TERRACES  OF  THE  CONNECTICUT  IN  THE  SPRINGFIELD  BASIN. 

The  fact  that  the  basin  was  left  by  the  ice  so  nearly  filled  up  to  the 
level  of  the  later  lake,  and  the  fact  that  the  contributions  to  the  lake  were 
almost  wholly  from  the  east  side,  caused  the  thread  of  the  cui-rent  through 


730  GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

the  lake  to  hug  the  western  shore;  and  as  the  river  took  the  place  of  the 
lake,  it  occupied  the  same  position  and  cut  very  soon  down  into  till  or  sand- 
stone, and  so  was  unable  to  swing  in  broad  oscillations,  as  in  the  deeper 
clay-filled  Hadley  basin.  From  the  notch  to  Smiths  Ferry  a  narrow  terrace, 
or,  for  a  distance,  two  narrow  terraces,  border  the  river  on  the  west.  On 
the  east  the  river  is  wearing  into  the  great  gorge  terrace  of  Dry  Brook  Hill, 
and  a  single  sand  slope  of  1 88  feet  touches  the  water's  edge.  From  the 
south  end  of  this  hill  to  Holyoke  the  first  position  of  the  river  was  much 
farther  east,  and  it  has  swung  west  to  its  present  place  and  built  on  the  east 
side  an  early  flood  plain,  long  since  abandoned,  and  the  river  has  now  cut 
its  bed  deep  in  the  sandstones  and  is  thus  prevented  from  oscillating. 
Doubtless  if  the  dam  below  were  removed  the  water  woitld  run  in  rapids 
over  this  ground,  as  it  does  over  the  rocks  above  Turners  Falls.  There  is 
in  all  this  distance  scarcely  a  trace  of  any  low  terrace  on  the  west  side  of 
the  river. 

Across  Chicopee  there  is  a  fine,  low  terrace  bounded  on  the  east  by  a 
high  scarp  of  the  high  terrace,  which  everywhere  shows  till  in  great  force 
beneath  the  sands  of  the  old  lake.  From  the  Chicopee  River  south  to  the 
south  line  of  the  town  the  high  terrace  scarp  comes  forward  to  the  river. 
Across  Springfield  there  is  developed  a  complicated  series  of  river  terraces. 
An  incomplete  terrace  borders  the  stream  opposite  and  above  Hampden 
Park.  The  business  portion  of  the  city  is  built  upon  the  normal  flood  plain 
of  the  river.  Above  this  are  two  well-marked  terraces,  which  send  back 
deep  lobes  to  the  north  and  south  of  the  armory  grounds,  up  old  water 
courses,  and  a  remnant  of  one  of  these  intermediate  terraces  is  preserved 
in  the  hill  north  of  the  Memorial  Church,  cut  off  possibly  by  an  oxbow, 
the  only  one  found  in  this  basin  upon  the  main  stream.  The  low  terrace 
contracts  to  nothing  on  the  south  line  of  the  town  and  widens  again  in 
Longmeadow. 

On  the  west  side  of  the  river  the  low  terraces  expand  south  of  Holyoke 
into  the  broader  meadows  of  West  Springfield  and  Agawam. 

The  sei'ies  in  all  this  distance  is  quite  complicated,  matching  the  oppo- 
site side  of  the  river.  There  is  across  West  Springfield  an  early  flood  plain 
raised  well  above  the  river,  and  around  the  entrance  of  the  Westfield  River 
the  incomplete  terrace  occupies  broad  areas  from  which  the  water  is  largely 
kept  out  by  artificial  embankments.  South  of  this  tributary,  across  Agawam, 
the  system  of  later  terraces  is  developed  with  a  beauty  not  exceeded  in  the 


THE  TERRACES  OF  THE  CONNECTICUT.  731 

whole  lengtli  of  tlie  State.  We  have,  beginning  back  at  tlie  mountain,  the 
broad  stretch  of  the  higli  lake  flats  (1  f),  sinking  into  a  more  limited  area  of 
lake  bottom  (1  b  t),  and  cut  into  this  is  a  series  of  later  terraces,  four  in 
nund-)er  (t't^),  much  broader  than  the  corresponding  ones  north  of  the 
Westliehl  River,  and  combining  with  the  terraces  of  this  latter  stream  to  form 
a  most  beautiful  succession  of  broad  meadows,  bounded  back  from  the  river 
by  sharp  slopes,  which  swing  in  great  (turves — representing  former  curves 
of  the  stream — up  which  one  mounts  to  reach  higher  terrace  flats  as  well 
characterized  as  those  below. 

THE  INCOMPLETE  TERRACES  AS   IliLUSTRATIONS  OF  THE  STAGES  IIST 

THE   GROWTH  OF  TERRACES. 

All  up  and  down  the  river  broad  sand  flats  may  be  seen  extending  out 
into  the  stream  at  a  level  but  little  above  low  water  and  on  the  concave  side 
of  bends,  as  north  of  the  knee  of  the  Hadley  bend  and  at  the  first  concavity 
below  the  Northampton  bridge. 

Generally  only  one  bank  of  the  river  is  wooded  at  a  given  section  of 
the  stream.  Going  up  or  down  stream,  one  comes  to  a  stretch  where  the 
growth  ceases  and  is  replaced  by  a  caving  bank,  beyond  which  the  bushes 
begin  again.  From  the  bushy  banks  the  shallows  extend  far  out,  and  the 
conditions  are  favorable  for  the  formation  of  islands.  Against  the  caving 
bank  lies  the  thread  of  the  stream.  Each  set  of  these  sand  flats  and  shallows 
is  connected  diagonally  across  the  stream  with  a  corresponding  set  on  the 
other  side,  and  at  low  water  a  series  of  disconnected  deep  water-pockets  lies 
in  the  line  of  the  thread  of  the  current,  alternating  against  the  right  and  left 
banks  of  the  stream,  and  so  much  of  the  water  seeps  through  the  sands  of 
the  shallows  between  the  pockets  that  the  bed  is  not  scoured  out  at  all 
between  these  long,  curved  deep-water  stretches. 

It  was  a  remarkable  and  interesting  discovery  of  Gen.  Theo.  G.  Ellis, 
of  Hartford,^  that  at  high  water  a  large  portion  or  the  whole  of  this  system, 
of  bars  is  scoured  out,  and  on  the  recession  of  the  flood  is  replaced  exactly 
in  its  old  place  and  with  its  old  dimensions,  as  a  curtain  held  up  by  the 
wind  sinks  to  its  old  place  as  the  wind  falls.  This  is  true,  of  course,  in  so 
far  as  the  banks  of  the  stream  above  and  below  are  unchanged,  for  these 
bars  are  the  mechanical  solution  of  a  complex  equation  in  hydraulics  and 
change  with  any  change  of  the  factors. 


'Survey  of  Connecticut  River:  Ex.  Doc.  101,  Forty-fifth  Congress,  second  session. 


732  GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

If  bushes  or  turf  strand  on  the  bar  and  take  root,  it  is  protected  and  its 
increase  is  accelerated,  and  it  grows  in  flood  time  above  the  low-water  level 
and  i-ises  as  an  island  or  promontory,  and  the  tendency  of  the  stream  to 
scour  out  everything  at  high  water  generally  keeps  open  a  channel  between 
it  and  the  mainland.  This  is  the  condition  of  Ellwells  Island,  just  north  of 
the  west  end  of  Noi-thampton  bridge.  In  the  time  of  canal  navigation, 
sixty  years  -ago,  the  channel,  33  feet  deep,  ran  right  under  the  present 
island,  and  in  digging  for  the  pier  of  the  new  bridge  old  boat  hooks  were 
fovnid  under  its  south  end. 

The  island  generally  joins  the  mainland  by  the  silting  up  of  the 
upstream  end  of  the  side  channel,  and  a  deep,  stagnant  inlet  runs  up  from 
its  south  end.  This  is  the  condition  of  two  broad  peninsulas  opposite  the 
"oxbow"  below  Hockanum  which  have  formed  since  1840. 

The  continued  growth  of  the  new  addition  to  the  flood  plain  takes 
place  by  material  brought  in  over  it  during  floods,  and  this  decreases  in 
rapidity  as  the  ground  rises,  and  soon  the  checking  of  the  current  as  it  rises 
over  the  flat  makes  itself  manifest  in  the  increased  deposition  along  the 
outer  border  of  the  flat,  and  a  "glacis  terrace"^  results,  sloping  sharply  to 
the  water  and  gradually  backward.  The  "glacis  terrace"  is  thus. a  case  of 
arrested  development  of  a  terrace.  The  groove  which  separates  the  new 
from  the  old  remains  preserved  for  a  long  time  and  often  permanently. 

Again,  as  the  waters  rise  over  the  growing  terrace,  they  are  arrested 
first  over  its  upstream  portion  and  thus  build  up  this  end  most  rapidly. 
This  is  most  beautifully  illustrated  in  the  terrace  which  begins  at  the  North- 
ampton bridge  and  extends  south  to  the  south  end  of  Hadley  street,  and  is 
bounded  by  the  road  which  leaves  the  main  road  at  the  bridge  and  joins 
Hadley  street  at  its  south  end.  This  road  runs  along  the  edge  of  the  former 
bank  of  the  river,  and  at  its  south  end  one  looks  down  upon  the  lower  plain, 
still  separated  by  a  shallow  inlet  which  runs  up  from  the  south.  North- 
ward, the  lower  plain  gradually  rises,  the  inlet  shallows  and  disappears,  and 
the  lower  terrace  is  a  complete  "glacis  terrace."  Still  farther  north  the 
lower  plain  continues  to  rise,  and  the  scarp  which  separates  the  two  becomes 
less  in  height  until  at  the  bridge  the  two  have  come  so  nearly  to  the  same 
level  that  one  might  easily  overlook  the  fact  that  the  newer  terrace  extends 

1  Hitchcock,  Surface  Geology,  1860,  p.  5. 


THE  OSCILLATIONS  OF  THE  CONNECTICUT.  733 

for  some  little  distance  alxnc  the  hvidg'e.  I  have  already  had  occasion  to 
describf  the  meadows  as  tunned  by  a  continued  repetition  of  this  process. 
(See  ii-  47.  ]).  T2(;.) 

ON  THK   OSCILIjATIONS    OF    THE   COK]ST:CTICUr  FROM    ITS  EAKLIEST 

POSITION. 

From  the  north  line  of  the  State  to  the  Sunderland  bridge  the  river 
everywhere  cut  down  rapidly  to  rock  and  has  not  swung  widely  to  east 
and  west,  but  has  been  condemned  from  the  beginning  to  rock  cutting. 

The  river  at  the  beginning-  took  its  course  across  the  Hadley  Lake 
bottom  along  the  deepest  line,  which  it  has  obliterated.  I  imagine  that  this 
line  was  very  near  its  present  position.  It  probably  swung  first  eastwardly 
to  its  eastern  limit,  at  the  "halfway  house"  on  the  Hadley  road.  It  is 
more  certain  that  from  this  eastern  limit  of  its  oscillation  it  has  moved  west 
regularly  and  silted  up  its  bed  behind  quite  rapidly  and  completely; 
this  is  shown  by  the  fact  that  the  Hadley  and  North  Hadley-Sunderland 
meadows  are  composed  of  series  of  elongate  and  coalescing  islands,  as 
detailed  on  ]3age  726.  It  has  swung,  then,  west  across  the  Hatfield  and 
very  far  west  across  the  Northampton  meadows,  and  regained  again  a  more 
central  position  by  cutting  off  its  oxbows.  During  its  swing  westward, 
across  the  Noi'thampton  Meadow  and  back,  it  has  lowered  itself  by  about 
7  feet  more  than  its  own  depth,  since  at  the  foot  of  Hadley  street  its  old 
bottom  sands  rest  upon  the  eroded  surface  of  the  Champlain  clays  at  a 
height  of  7  feet  above  the  low  water  of  the  river.  This  height  may  be  some- 
what increased  if  we  allow  for  the  influence  of  the  Holyoke  dam. 

From  the  Holyoke  notch  south  to  the  Holyoke  dam  the  river  early 
became  entangled  in  rock  and  has  cut  only  vertically.  From  the  dam  south 
the  earliest  position,  or,  more  accurately,  the  earliest  restorable  position, 
may  be  found  by  following  down  the  outside  edge  (counting  from  the  river) 
of  the  oldest  terrace  of  erosion  (t^).  This,  the  highest  terrace  of  this  later 
series,  is  found  only  on  the  west  side  of  the  stream  from  Holyoke  south, 
and  then  is  for  a  long  way  present  on  the  east  side,  across  Springfield,  then 
being  transfeiTed  to  the  west  side,  across  Agawam.  This  represents  the 
sinuous  position  of  the  stream  from  the  Holyoke  Falls  southward  at  a  time 
when  it  had  first  established  its  course  across  the  lake  bottom,  and  from 
which  it  has  swung  to  form  its  later  and  lower  terraces,  ending  in  its  present 
temporary  position. 


734  GEOLOGY  OF  OLD  HAMPSHIEB  COUNTY,  MASS. 

THE   OXBOWS   OF  THE   CONNECTICUT. 

lu  the  Montague  Lake  the  valley  was  too  narrow,  the  rock  comes  too 
near  the  surface,  and  the  earlier  deposits  were  too  thick  to  allow  of  broad 
bends  and  cut-offs.  Several  old  river  beds  there  seem  rather  to  have  been 
formed  by  the  building  up  of  an  island  in  midstream  and  the  after  limita- 
tion of  the  current  to  one  side  of  it  without  filling  up  the  abandoned  portion. 

Over  the  broad  bottom  of  the  Hadley  Lake  the  stream  had  more  free- 
dom, and  in  the  Hatfield  and  Northampton  meadows  are  two  most  interest- 
ing series,  containing  in  one  case  four  and  in  the  other  thi'ee  old  cut-off 
oxbows,  and  between  is  the  great  Hadley  bend,  where  the  river  runs  about 
6  miles  to  advance  southward  1  mile,  and  threatens  to  take  a  straight  course 
down  through  Hadley  street.     (See  map,  PI.  XXXV,  in  pocket.) 

In  Hatfield  the  oldest  oxbow  runs  down  west  of  the  village.  A  part 
of  the  unfilled  bed  of  the  second  is  the  Great  Pond.  The  third  is  repre- 
sented by  a  sickle-shaped  pond  east  of  the  road  going  north  from  the  village, 
and  the  completion  of  the  fourth  has  in  very  recent  years  transferred  a 
fragment  of  Hadley  to  the  west  side  of  the  river. 

In  Northampton  a  sickle-shaped  pond,  at  the  western  edge  of  the 
meadow,  represents  the  oldest  cut-off.  The  second  remains  in  a  smaller 
pond  near  the  western  curve  of  the  third — the  oxbow  par  excellence — 
which  is  still  a  ring-shaped  pond,  in  communication  with  the  main  stream 
beneath  the  bridge  of  the  Connecticut  River  Railroad.  This  was  cut  off 
during  the  flood  of  1840.  Figures  of  the  river,  as  seen  from  Mount  Hol- 
yoke  before  1840,  with  the  fine  curve  of  the  stream  from  1840  to  1845, 
after  the  cut-off  and  before  the  silting  up  of  the  mouths  of  the  oxbow,  are 
given  in  the  publication,  Northampton,  Meadow  and  City.^ 

ON  THE   DEFLECTION  OF  STREAMS  TO  THE  EIGHT  BANK. 

The  Connecticut  River  between  Mount  Toby  and  Mount  Holyoke, 
about  8  miles  in  a  straight  line,  flows  across  the  broad,  level  bottom  of  the 
ancient  lake  through  thick,  very  fine-grained,  and  very  homogenous  deposits. 
It  is  thus,  together  with  its  tributaries,  favorably  situated  to  give  evidence 
concerning  the  possible  influence  of  the  earth's  rotation  upon  the  erosion  of 
streams  according  to  Ferrell's  law,  that  a  stream  under  the  influence  of  the 

1  F.  N.  Kneeland,  Northampton,  1894,  p.  36. 


TEUKACES  AROUND  A  WATERFALL.  735 

earth's  rotatidu  always  tends  to  weai-  its  riylit  bank.  Accordingly,  it  is 
interesting"  that  the  i-iver  has  constantly  made  and  cut  off  oxbows  on  the 
west — that  is,  the  right  side — and  never  on  the  east  side.  It  has  successively 
cut  off  four  bends  in  Hatfield  and  three  in  the  south  part  of  Northampton, 
ami  has  also  made  the  great  Hadley  bend,  which  it  has  long  threatened  to 
change,  into  an  oxbow,  and  it  has  never  made  great  bends  out  to  the  eastward. 
The  same  testimony  also  comes  in  a  striking  way  from  the  tributaries 
I  have  for  several  years  given,  as  practical  work  for  advanced  students,  the 
mapping  of  portions  of  these  tributaries  of  the  Connecticut,  which  run  for 
long  distances  ovit  over  the  old  lake  bottom,  and  on  counting  up  the  sharp 
bends  and  oxbows  on  the  right-hand  side  of  the  stream  the  proportion  was 
as  great  as  30  to  1  in  favor  of  this  side  as  against  the  opposita 

RIVER  TERRACES  AROUND   A  RECEDING  WATERFALL. 

The  flood  plain  of  a  river  tends  to  reach  the  full  height  of  highest 
flood,  and  on  approaching  a  fall  this  height  diminishes  greatly,  as  the  waters 
as  they  go  over  the  fall,  because  of  their  increased  rapidity,  rise  to  only  a 
small  fraction  of  their  normal  height.  At  the  foot  of  the  fall  or  at  the  mouth 
of  the  canyon  below  the  fall  the  flood  plain  begins  again  at  a  level  as  much 
below  that  above  the  fall  as  the  descent  of  the  waters  demands. 

Thus  at  Turners  Falls  the  flood  plain  above  "the  falls  is  only  7  feet 
above  the  level  of  the  waters,  and  the  height  above  the  waters  before  the 
erection  of  the  dam  was  probably  not  many  times  greater,  while  the  flood 
height  of  the  river  here  is  30  feet.  If  now  the  falls  recede,  leaving  remnants 
of  this  low  flood  plain,  it  will  hang  over  the  canyon  with  a  height  above 
the  river  equal  to  its  original  height  plus  the  height  of  the  fall;  and  this  is 
the  case  at  Turners  Falls  and  at  Holyoke,  where  the  old  flood  plain  is  con- 
tinuous from  above  the  falls  south  along  the  sides  of  the  gorge  formed  by 
the  recession  of  the  falls. 

If,  further,  the  stream  by  its  oscillations  below  the  falls  builds  a  flood 
plain  at  the  lower  and  newer  level,  we  have  the  curious  result  that  the 
flood  plain  above  the  falls  will  extend  downstream  above  the  flood  plain 
below  the  falls,  the  two  thus  overlapping  at  two  different  levels.  Distinct 
traces  of  this  appear  at  both  of  the  falls  on  the  river,  especially  at  South 
Hadley  Falls,  where  the  flood  plain  of  the  river  is  continued  out  over 
the  lower  one  for  a  long  distance.      This   makes  a  difficulty  in  coloring 


736  GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

the  terraces,  and  I  have  on  the  map  continued  the  low-terrace  color  down  the 
canyon  side  in  dots  to  distinguish  it. 

THE  TERRACES   OF   TRIBUTARIES. 

The  deep,  land-locked  basins  cut  in  the  lake  beds  by  the  tribiitaries  of 
the  Connecticut  are  among-  the  most  remarkable  orographic  features  of  the 
valley.  Each  stream  has  first  built  out  the  great  delta  plain  and  then 
excavated  its  basin  on  the  sinking  of  the  main  stream.  They  have  this 
peculiarity  in  common.  Each  stream  emerges  from  its  gorge  in  the  crys- 
talline rocks,  rims  across  its  former  delta,  and  passes  through  a  short  rocky 
gorge  just  above  its  mouth,  and  the  stream  has  thus  been  fastened  at  two 
points  like  the  string  of  a  musical  instrument,  and  has  vibrated  between 
these  two  points  to  form  its  closed  basin.  It  has  eroded  with  great  violence 
because  it  has  had  the  rapid  fall  across  the  crystalline  rocks. 

The  Deerfield  and  Westfield  River  basins  are  the  most  extensive  and 
interesting  examples,  the  one  occupied  by  the  most  romantic  and  sleepy 
old  town  in  the  valley,  the  other  by  a  typical,  unattractive,  manufacturing 
town.  These  rivers  have  reoccupied  their  old  gorges  in  the  trap  ridges, 
as  already  explained  (p.  512).  The  others,  Green  River,  Millers  River, 
Mill  River  in  Northampton,  and  Cushmans  Brook  at  the  Golden  Gate  in 
Amherst,  have  by  chance  strack  rock  bottom  as  they  cut  down  thi-ough 
their  deltas,  and  thus  the  mouths  of  their  basins  are  closed  below,  as  are  the 
first  two. 

The  basins  are  bounded  on  all  sides  by  high  scarps,  and  over  the  low 
meadow  bottoms  are  many  abandoned  channels  caused  by  ice  obstniction 
in  spring,  which  in  the  Deerfield  bottom  are  developed  into  a  most  compli- 
cated network. 

A  prominent,  flat-topped  hill,  called  Pine  Hill  or  Pine  Nook,  its  surface 
on  a  level  with  the  adjacent  high  terrace,  rises  in  the  midst  of  the  Deerfield 
Meadow  and  has  doubtless  been  cut  off  by  an  old  oxbow  of  the  river,  and 
a  smaller  but  similar  one,  which  has  been  called  an  Indian  mound,  but  has 
the  structure  of  the  smTounding  delta  sands,  stands  in  the  basin  of  Mill 
River  above  Florence. 


TUE  TEKUACES  OF  THE  CONNECTICUT.  737 

AX  OLD  <)XIJO\V  OF  FORT  lUVEU. 

From  the  south  end  of  Hadley  street  one  may  follow  the  Champlain 
clays  continuously  for  a  long  distance  south  in  the  river  bank.  Near  where 
they  sink  below  the  water  a  terrace  scarp  belonging  to  Fort  River  is  cut 
off  in  the  bank  of  the  Connecticut.  The  last  house  passed  in  going  south 
from  Hadley  and  before  crossing  the  bridge  over  Fort  River  stands  on  the 
edo-e  of  the  completed  flood  plain  of  the  Connecticut  and  looks  down  over 
this  scarp  to  a  lower  plain,  formerly  part  of  the  flood  plain  of  Fort  River, 
which  here  runs  parallel  to  and  just  east  of  the  Connecticut.  In  fig.  48,  a 
represents  the  southern  termination  of  the  Champlain  clays,  which  a  few 
feet  north  furnished  the  leaves  described  on  page  718,  and  still  farther  north 
abound  in  clay  stones;  5,  the  bottom  sands  of  the  Connecticut  when  it 
flowed  at  a  level  higher  than  at  present  by  an  amount  somewhat  greater 


CONN  ft.FLQOO  ^LMN  -^-^^..^^ \'-.''\  -  -  :     ''.^.-^^^ '''''^^'^■^^^^■-J.^.^ZjT^- .■    ZT^^     ~  IZ7{IzIZT^J^^'^~^''^^^^^^^-'^^^ 


ccNN,  /f  s^NOs     b.  '^^^^^^p^l'S—    ri — '-^; "  ^'^_    .,..._^._     '^Tl— —^'•'^^''^^^'^-^  :r-,-^r:-^-^-^=^^^-^^^~  •^\'rr^\'-rm~mY\uu^mt^mi£w\im  a^"  ■'■  i'-  'i  iV '  Yi  'ifi'rti'i'  '^i  Ji'TB~"'  ^  four  ft,  SAMOS 


than  its  own  depth.  These  are  coarse  to  medium  grained  straticulate 
sands,  which  rest  unconformably  upon  the  clay  and  extend  with  a  thickness 
of  20  feet  to  the  point  where  the  old  Fort  River  terrace  scarp  is  cut  off  in 
the  present  river  bank.  Here  these  sands  end,  their  horizontal  beds  abut- 
ting unconformably  against  c  and  e,  except  that  at  lowest  water  their  lower 
beds  can  be  traced  beneath  c  for  the  whole  length  of  the  exposure. 

The  scarp,  partly  exposed  and  partly  submerged,  against  which  these 
sands  end,  registers  the  farthest  northward  swing  of  Fort  River  in  throwing 
out  an  oxbow  here  on  its  west  side;  c,  which  is  a  fine,  horizontally  bedded 
and  straticulate  sand,  is  the  bottom  sand  of  Fort  River  as  it  swung  across 
its  flood  plain;  cl  and  cV  are  two  cross-sections  of  the  old  oxbow  of  the  trib- 
utary, now  cut  into  by  the  main  stream.  At  d  the  stream  plainly  flowed 
toward  the  west — that  is,  toward  the  reader;  at  (i',  toward  the  east;  and  the 
Connecticut  has  cut  across  this  old  oxbow,  as  indicated  by  the  dotted  lines. 

These  old  river  beds  are  the  exact  equivalents  of  the  present  bed  of 
Fort  River — a  stratified  deposit  of  leaves,  twigs,  logs,  and.  seeds  in  fine 
MON  xxix 47 


738  GEOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 

whitish  clay,  abundantly  pierced  by  the  vertical  pipestem  concretions,  espe- 
cially in  its  upper  portion,  where  it  grades  into  e,  a  thick  stratum  of  loess, 
which  is  10  feet  thick  over  all  the  lower  plain,  and  still  thicker  where  it 
projects  downward  to  fill  the  old  river  beds.  It  rises  up  the  terrace  scarp 
with  a  thickness  of  3  feet,  and  is  continuous  over  the  upper  plain  with  a 
thickness  of  6  feet.  This  represents  the  accumulated  deposits  of  the  Con- 
necticut in  flood  time,  laid  down  since  Fort  River  abandoned  its  bed  at 
d  and  d! .  This  stream  now  runs  immediately  adjacent,  with  its  surface  coin- 
cident with  that  of  the  Connecticut.  When  it  occupied  this  old  oxbow  it 
flowed  at  a  level  13  feet  higher,  and  this  represents  certainly  more  than 
half  of  the  amount  by  which  the  Connecticut  has  lowered  its  bed  in  the 
bottom  of  Hadley  Lake  since  it  shrunk  to  its  present  size.  This  would 
assign  to  the  fossils  found  here  an  age  about  intermediate  between  those 
of  the  Champlain  clays  below  and  the  present  time,  or  somewhat  nearer  to 
the  present  flora  than  to  the  older;  and  the  habits  of  the  fossils  themselves 
agree  with  this,  and  indicate  a  climate  like  that  of  northern  Vermont  or 
Canada.  It  is  interesting  that  a  fragment  of  charcoal  from  some  light,  open- 
grained  wood  was  found  in  the  midst  of  the  matted  leaves  of  the  leaf  bed 
and  was  certainly  of  the  same  age  with  them.  It  was  about  as  large  as  a 
walnut. 

FOSSIIiS  OF  THE  TERRACE  PERIOD. 

VERTEBRATES. 

Mastodon  americanus. — In  1872  Dr.  Edward  Hitchcock,  jr.,  writes:  "I 
have  seen  and  identified  a  mastodon's  molar  which  was  found  in  the  town 
of  Coleraine,  Massachusetts.  It  was  shoveled  out  of  a  muck  bed  on  the 
farm  of  Elias  Bardwell." '     The  tooth  is  still  in  Mr.  Bardwell's  possession. 

MOLLTJSKS. 

In  digging  in  a  marl  pit  which  has  formed  by  the  filling  of  a  small 
pond  on  the  surface  of  the  till  on  the  farm  of  Fred  Conant,  at  East  Shel- 
burne,  large  quantities  of  white  fresh-water  shells  are  at  times  thrown  out. 
They  are  very  well  preserved,  and  consist  of  the  following  species: 

Lymnea  elodes  Say. — Length,  30  """.     Common. 

Planorbis  trivolvis  Say. — Large  diameter,  25™™;  small  diameter,  18 
Common. 

'  Am.  Joiir.  Sci.,  3cl  series,  Vol.  Ill,  p.  146. 


mm 


FOSSILS  OF  THE  TEERAOE  TEEIOD.  739 

Plaiiorhis  jMirvus  Saj-. — Abundant.     Diameter,  6.5    '". 

Flsidmm  variahilc  Fi'ime. — Abundant.     Length,  2"^"';  width,  2i'"'^. 

PLANTS. 

Banuncuhis  aquatilis  L. — A  single  well-preserved  plant.  This  and  the 
following,  with  one  exception,  are  from  the  old  oxbow  in  Hadley,  described 
on  page  737. 

Acer  saccliarimmi  Wang. — Leaves.     Eare. 

Primus  virginiana  L. — Seeds  very  abundant;  leaves  abundant.  "River 
banks.     Common,  especially  northward"  (Gray). 

Platamis  occidentalis  L. — Leaves,  large  branches,  and  balls  found  in 
great  abundance. 

Matted  masses  several  inches  thick  and  many  feet  broad  consist  almost 
entirely  of  leaves,  many  of  the  largest  size.  Large  branches,  often  very 
much  flattened  and  still  covered  with  the  characteristic  bark,  occur  fre- 
quently. 

In  several  cases  delicate  hollow  globes  of  sand,  like  globes  of  lace  or 
Chinese  hollow  ivory  balls,  have  been  formed  by  the  penetration  of  the 
fine  sand  to  the  surface  of  the  central  ball,  and  its  spreading  in  the  regular 
interstices  which  surroimd  each  point  of  attachment  of  a  seed,  where  the 
grains  have  been  slightly  agglutinated  and  left  as  a  globe  of  lace  on  the 
rotting  of  the  seed  ball.  The  extreme  northern  range  of  the  species  is 
Lake  Champlain  and  Montreal.-^ 

Jiiglans  cinerea  L. — Dwarf  nuts,  1^  to  If  inches  long,  f  to  ^  inch  wide; 
less  deeply  sculptured  than  the  form  now  common  here.  In  one  case  nine 
specially  prominent  ridges  are  present.  In  another  the  ridges  are  more 
rounded,  broad,  and  irregular  than  now.  The  species  now  extend  south  to 
Georgia,  and  north  through  Canada,  but  this  dwarf  form  would  seem  to 
indicate  'a  station  near  its  south  border. 

Garya  cmiara,  Nutt. — At  the  old  oxbow  occurred  an  impression  of  an 
exterior  inclosing  a  cast  of  the  interior  of  a  single  specimen  in  rusty  clay. 
Also  well-preserved  nuts  in  abundance  were  given  me  by  Dr.  Edward 
Hitchcock,  as  found  at  extreme  low  water  below  the  mouth  of  Fort  River, 
opposite  the  fourth  pile  of  Mclndoes's  boom,  counting  from  the  north — 
rounded,  thin-shelled  nuts,  averaging  somewhat  larger  than  nuts  of  the  same 

'  Michaux,  Sylva,  vol.  6,  p.  56. 


740       GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

species  from  Burlington,  Vermont.  Sizes:  Burlington,  17.5  to  19°"";  Con- 
necticut River,  smallest,  19  to  20.5°"";  largest,  22  to  27"'".  "Barely  1  inch 
(25.5"")  long,  thin  walled"  (Grray).  "Northern  boundary,  Vermont" 
(Michaux).  I  am  informed  that  but  a  single  tree  of  the  species  is  now- 
found  in  the  county,  and  this  upon  the  Hatfield  Meadow. 

Quercus  alba  L. — A  few  well-preserved  leaves. 

Querais  coccinea  Wang.,  var.  ambigua. — Leaves  and  abundant  acorns  in 
all  stages  of  growth.  "The  gray  oak  appears,  by  my  father's  notes,  to  be 
found  farther  north  than  any  other  species  in  America."  (Michaux,  Sylva, 
vol.  1,  p.  98.) 

"Along  the  northern  borders  to  Lake  Champlain  and  northward." 
(Gray,  Manual,  1872,  p.  434.) 

Fagus  ferruginea  Ait. — Next  to  the  sycamore,  the  most  abundant  plant 
represented.  Leaves  of  full  size,  large  fragments  of  the  wood  and  bark  and 
nuts  alike  abundant,  the  latter  very  large  and  surpassing  in  size  those  now 
found  in  the  vicinity. 

"Common,  especially  northward."     (Gray's  Manual,  p.  455.) 

"Almost  exclusively  confined  to  the  northeastern  United  States  and  to 
the  provinces  of  Canada."     (Michaux,  S3dva,  vol.  5,  p.  22.) 

Bet'ula  alba  L. — Large  branches  with  bark  marked  exactly  as  in  the 
common  white  birch. 

Besides  these  many  other  indeterminate  plants  were  studied — willow 
leaves,  grape  vines,  grasses,  liliacese,  lycopodium,  hchens,  various  seeds,  and 
even  a  flower. 

THE  PLEISTOCENE  BEETLES   OF  FORT  RIYEB,  MASSACHUSETTS. 

By  Samuel  H.  Scuddbr. 

The  insects  found  by  Prof.  B.  K.  Emerson  in  the  old  bed  of  Fort 
River  in  Hadley,  Massachusetts,  near  its  entrance  into  the  Connecticut, 
have  no  special  interest  beyond  the  fact  that  they  are  the  first  insects 
found  in  such  deposits  in  New  England.  They  consist  wholly  of  Coleop- 
tera,  and  represent  five  species  and  four  families,  viz:  Carabidae,  Dytiscidse, 
Elateridee,  and  Chrysomelidae,  the  latter  having  two  species.  At  least  three 
of  the  insects,  perhaps  all,  belong  to  species  not  now  known  to  exist,  but 
so  far  as  can  be  told  with  any  certainty,  all  belong  to  existing  genera, 
though  some  doubt  may  reasonably  be  claimed  for  the  single  species  of 


PLATE   XXIII. 


741 


PLATE    XXIII. 

PLEISTOCENE  BEETLES  OF  FORT  RIVER,  MASSACHUSETTS. 
(The  original  drawings  are  by  J.  Henry  Blake.) 

Fig,  1.  Cymindis  extorpescens ;  elytron  f. 

2.  Corymbites  asthiops  (Herbst)f ;  prothorax  ^. 

3.  Dytiscidfe  sp.,  perhaps  a  Matus;  metasternum  f. 

4.  The  same;  a  portion  further  enlarged  to  show  the  surface  sculpture  ^. 

5.  Donacia  elougatula;  elytron  f. 

6.  Saxinis  regularis ;  portion  of  the  right  elytron  highly  magnified  to  show  the  surface  sculpture  ^. 

7.  The  same;  dorsal  view  of  the  beetle  f. 
742 


U.   a.   OCOLOOtCAi.  8URVEV 


MONOGRAPH  XXIX       PL.    XXIII 


11 

m 


^ 

PLEISTOCENE  BEETLES  OF  F.       .    RIVER,   MASSACHUSETTS. 


TLEISTOCENE  15EETLES  OP  FORT  RIVEE.  743 

Dvtiscida>  and  one  of  the  two  species  of  Chrysomelida;.  This  is  rather 
surprising-,  but  is  what  has  been  found  to  some  degree  in  American  Pleisto- 
cene dejiosits,  the  insects  of  which  appear  to  show  less  close  relations  to 
their  successors  on  the  spot  than  is  commonly  the  case  in  Europe,  and  in 
consequence  relatively  little  light  can  be  shed  upon  the  climatic  conditions 
of  the  time  by  their  remains.  In  the  present  case  the  information  is 
meager  and  gives  no  certain  clue.  The  existing  species  most  nearly  allied 
to  the  Pleistocene  Cymindis  (Carabidse)  occurs  from  Massachusetts  to 
Florida,  and  is  more  common  in  the  South  than  in  the  North;  our  single 
species  of  Matus  (Dytiscidse)  is  found  in  Canada  and  in  the  Northern  States 
from  Massachusetts  to  Iowa,  but  also  in  Missouri  and  Florida;^  Corymbites 
(Bthiops  (Elateridae)  occurs  from  Massachusetts  to  Pennsylvania  and  Ohio; 
the  Donacia  (Chrysomelidse)  most  nearly  allied  to  the  fossil  species 
described  below  appears  to  be  one  known  from  the  Pleistocene  of  Italy; 
while  the  species  of  Saxinis  (Cluysomelidse)  most  closely  related  to  the 
Pleistocene  form  here  figured  is  a  northwestern  species,  coming  from 
Vancouver,  Oregon,  and  California,  and  also  from  Utah,  Colorado,  and 
Wyoming.  It  is  plain,  then,  that  a  considerably  larger  assemblage  of 
forms  must  be  obtained  to  give  any  evidence  of  value.  The  following  are 
the  species  found: 

Family  CARABIDtE. 
Cymindis  extorpescens. 

PI.  XXIII,  fig.  1. 

A  single  elytron,  representing  a  species  aboiit  as  large  as  C.  cribricoUis 
Dej.,  but  more  nearly  allied  to  C.  elegans  Lee.  in  the  reduction  of  the  inter- 
stitial punctures  to  a  single  row,  seems  to  be  entirely  distinct  from  any  of 
our  species  of  that  genus  in  the  reduction  of  the  striae  to  a  series  of  short 
longitudinal  dashes  separated  from  one  another  by  their  own  length,  while 
the  interstitial  punctures  are  more  lightly  impressed,  arranged  in  single 
straight  rows,  and  separated  by  twice  their  own  length.  The  elytron  is 
piceous,  with  a  very  faint  bluish  reflection. 

Length  of  elytron,  6.35°"";  width,  2.5°"°. 

'For  information  on  the  distributiou  of  American  Coleoptera  I  always  rely  upon  the  ready  and 
efficient  aid  of  my  friend,  Mr.  Samuel  Henshaw,  of  Cambridge. 


744       GEOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 

Family  DYTISCID^. 
DytiscidcR  sp. 

PI.  XXIII,  figs.  3,  4. 

The  metastei'num  of  a  species  of  Dytiscidae  is  among  the  fragments 
obtained.  It  is  nearly  complete,  and,  of  all  with  which  I  have  been  able 
to  compare  it,  most  resembles  that  of  Matus,  particularly  on  account  of  the 
depth  of  the  median  groove,  the  form  and  relative  abbreviation  of  the 
rounded  intercoxal  prolongations,  and  the  shape  of  the  coxaj,  and  it  agrees 
very  well  in  size  with  our  single  species,  M.  licarinatus.  As,  however,  it  is 
not  nearly  so  long  in  proportion  to  its  breadth  as  in  that  species,  and  nar- 
rows remarkably  from  behind  forward,  it  hardly  seems  possible  to  refer  it 
to  that  genus,  and  I  find  no  other  with  which  I  can  so  well  compare  it. 
Instead,  also,  of  being  faintly  and  rather  sparsely  punctulate,  as  in  M. 
bicarinatus,  the  surface  is  feebly,  longitudinally,  and  undulately  striate,  and 
of  a  dull  piceous  color.  In  the  general  form  of  the  metasternum  it  more 
nearly  resembles  an  Agabus. 

Length  of  metasternum,  3"™;  breadth  posteriorly,  5""°. 

Family  ELATERID^. 
Corymhites  athiops  (Herbst)l 

PI.  XXIII,  fig.  2. 

The  prothorax  of  an  elaterid  of  a  piceous  color  is  referred  here  with 
some  doubt.  There  are  but  two  or  three  of  our  species  which  have  a  pro- 
thorax  large  enough  to  compare  with  it,  but  the  size  and  general  propor- 
tions, and  especially  the  punctation  of  the  surface,  agree  perfectly  with 
C.  mtliiops.  It  differs  from  that,  however,  in  the  greater  slenderness  of  the 
produced  posterior  outer  angles,  the  sides  are  more  strongly  convex  on  the 
posterior  half,  and  it  is  not  narrowed  to  nearly  the  same  extent  anteriorly. 
This  last  point  makes  its  reference  here  very  doubtful,  but  until  further 
remains  are  found  it  seems  best  to  place  it  here  with  a  mark  of  doubt. 

Length  of  prothorax  along  the  median  line,  5.35°"°;  greatest  breadth, 
5.25"". 


PLEISTOCENE  BEETLES  OF  EORT  IIIVER.  745 

Family  CHRYSOMELID^. 

Tribe  Donaciini. 
JDonacia  elongatula. 
PI.  XXIII,  %.  5. 

A  siuf'-le  nearly  perfect  left  elytron  appears  to  represent  a  species  not 
hitherto  known,  but  apparently  most  nearly  allied  to  I),  lignitum  Sord.,  from 
the  Italian  Pleistocene.  It  is  somewhat  more  than  three  times  as  long  as 
broad,  tapering  from  the  middle  to  the  nontruncated  apex,  before  which  the 
outer  margin  is  more  strongly  but  very  regularly  curved,  with  no  sudden 
change  of  direction.  Besides  the  marginal  groove,  there  are  in  the  basal 
half  ten  parallel  strise  with  delicate  longitudinal  punctures,  but  in  passing 
from  the  base  to  the  apex  the  two  middle  unite  just  before  the  middle  to 
form  a  single  stria,  and  just  beyond  the  middle  they  are  joined  by  the 
fourth  from  the  inner  margin.  No  others  unite  until  shortly  before  the  apex, 
when  the  third  and  fourth  from  the  inner  margin  unite  and  terminate,  and 
halfway  from  here  to  the  apex  all  but  the  outer  ones  approach  and  termi- 
nate, the  outer  ones  acting  similarly  at  the  very  apex.  The  surface  is  shining 
piceous. 

Length  of  the  fragment,  7.25'°'^;  probable  length  of  elytron,  T.e"""; 
breadth  in  middle,  2.2°"^. 

Tribe  Clythrini. 

Saxinis  regularis. 

PI.  XXIII,  figs.  6,   7. 

The  most  complete  specimen  found  in  these  beds  is  a  chrysomelid, 
with  the  last  abdominal  segment  exposed  and  callous,  which  with  its  form 
indicates  one  of  the  Clythrini,  It  is  slightly  larger  than  and  of  a  similar 
form  with  8.  saucia  Lee,  though  it  differs  decidedly  from  it  in  the  details  of 
the  form  and  structure  of  the  elytra.  The  prothorax  is  crushed  and  mis- 
shapen, so  that  nothing  more  can  be  said  of  it  than  that  it  differs  from  that 
of  Saxinis  in  its  lesser  breadth,  being  decidedly  narrower  at  base  than  the 
elytra,  and  on  this  account  it  is  exceedingly  doubtful  if  it  should  be  placed 


746       GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

at  all  in  that  geniis,  or,  in  fact,  in  any  other  of  the  American  Clythrini. 
The  elytra  differ  from  those  of  S.  saucia  mainly  in  having  the  abbreviated 
apex  less  rounded  and  more  squarely  truncate,  the  inner  a^jical  angle  espe- 
cially being  far  more  angulate;  as  there,  both  outer  and  sutural  borders  are 
delicately  margined,  and  the  general  proportions  of  the  elytra  are  much  the 
same  (in  this  respect  resembling  it  rather  than  our  other  species  of  Saxinis), 
but  they  are  a  little  and  gradually  narrowed  on  the  apical  half,  while  nearly 
equal  in  S.  saucia;  besides  the  punctures  which  adjoin  the  outer  margined 
border,  the  elytra  have  ten  very  straight  and  regular  equidistant  series  of 
delicate  punctures,  which  are  short  oval,  those  in  each  row  sej)arated  from 
their  neighbors  by  more  than,  usually  about  twice,  their  own  length,  and 
the  general  surface  is  sparsely  covered  with  excessively  delicate  hairs 
scarcely  longer  than  the  punctures.  The  general  color  is  a  uniform  shining 
piceous  with  a  slight  greenish,  metallic  tinge,  the  metallic  green  being 
decided  in  the  punctures.  The  last  abdominal  segment  shows  a  slight  dull 
median  ridge. 

Lengthof  body,  8™"";  of  elytra,  6.5  ™™ ;  breadth  of  base  of  prothorax, 
3.1 '"'";  of  each  elytron,  2.5  ="". 

THE   REPULSIOlSr  OF  TEIBTJTARIES.i 

Oscar  Peschel,^  from  his  orographic  studies,  notes  the  tendency  of  a 
tributary  to  run  a  long  distance  near  and  nearly  parallel  to  its  primary.  In 
all  the  tributaries  which  enter  the  Connecticut  across  the  broad  lake  deposits 
between  Mount  Toby  and  Mount  Holyoke  this  is  very  marked.  They  all 
run  out  through  the  old  bordering  bench  (1  s  h)  in  deep  gorges,  then  take  a 
straight  course  down  over  the  old  lake  bottom  (1  b  t),  following  its  slope,  but 
when  they  reach  the  oldest  terrace  flat  formed  by  the  river  in  its  oscillations 
after  the  shrinking  of  the  lake,  they  bend  abruptly  south  and  continue  as 
far  as  possible  to  run  nearly  parallel  to  the  main  stream,  and  when  they 
enter  the  latter  it  is  by  a  sudden  bend  at  right  angles.  This  will  be  clearly 
seen  by  an  inspection  of  the  map  (PI.  XXXV,  in  pocket),  or  of  the  North- 
ampton and  Belchertown  sheets. 

First,  the  brooks  north  of  Sunderland  village,  on  the  east  side  of  the 

'  See  PI.  XXXV,  in  pocket  at  end  of  volume. 
s  Vergleichende  Erdkunde,  1878,  p.  141. 


THE  REPULSION  OP  TRIBUTAEIES.  747 

river,  do  not  show  the  pecuHarity,  since  the  erosion  terraces  ai'e  there  nar- 
row or  wanting,  but  the  five  brooks  sovith  show  it  most  clearly.  Cuslimans 
Brook  (called  Mill  River  on  the  new  map)  runs  down  west  of  Mount 
Warner.  The  next  two  brooks  south  do  the  same,  and  then  Fort  River,  the 
last  of  the  series,  illustrates  the  rule  in  the  most  striking-  manner,  and  indeed 
formerly  ran  much  farther  south  than  now,  parallel  with  the  Connecticut, 
and  entered  the  latter  above  Hockanum  at  the  boat  landing  of  the  Mount 
Holyoke  House.  This  has  here  plainly  the  following  explanation:  The 
water  sank  very  suddenly  in  the  lake,  and  tbe  oldest  position  of  the  present 
river  of  which  any  trace  remains  was  the  eastern  edge  of  the  ten-ace  system. 
On  this  sinking  of  the  lake  water  the  streams  followed  it  by  the  shortest 
course,  cutting  gorges  in  their  old  deltas,  and  at  one  time  each  one  joined 
the  main  stream  at  the  point  where  it  at  present  cuts  the  boundary  between 
the  lake  bottom  (1  b  t)  and  the  terrace  system  (tM^).  As  the  Connecticut 
swung  west  and  built  up  its  terrace  behind  it  the  tributary  elongated  and 
kept  its  com-se  across  this  newly  formed  terrace,  and  since  this  terrace  flat 
or  flood  plain  was  built  up  as  a  series  of  bars  which  grew  to  be  islands, 
behind  each  of  which  there  is  for  a  long  time  a  long  groove  opening  south 
(see  p.  726),  the  brook  occupied  this  and  entered  the  main  stream  round  its 
south  end,  and  at  last  this  operation,  many  times  repeated,  gave  the  streams 
their  present  course. 

It  was  the  observation  and  study  of  this  law  several  years  ago  which 
caused  me  to  doubt  the  then  prevalent  idea  held  by  those  most  competent 
to  judge,  that  the  Connecticut  Valley  had  been  filled  up  to  the  height  of  its 
high  ten-ace — the  lake  bench — and  then  excavated,  and  led  me  to  map  the 
terraces,  as  I  have  done,  into  (a)  a  high  bench  or  string  of  deltas  bordering 
the  valley;  (b)  a  succession  of  lake  bottoms  sloping  from  the  above  center- 
ward  and  broadening  in  each  of  the  wider  stretches  of  the  valley,  and  (c)  a 
comparatively  small  area  occupied  by  the  "oscillation  terraces"  of  the  river 
proper — the  "meadows." 


748  GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

DUlSrES  AKD  WIND   LOESS.' 

President  Hitchcock  notes  ^  the  dunes  in  Montague  and  Hadley,  and 
in  the  east  part  of  Hadley  south  of  the  road,  and  their  motion  southeast- 
wardly.^  The  lake  bottom  in  Northfield  is  strikingly  cut  up  by  great  dunes 
over  the  whole  of  the  Beers  plain,  and  farther  south  in  Montague  one  can 
see  where  they  have  crept  upon  the  west  slopes  of  the  islands  which  rose  in 
the  midst  of  the  old  delta  of  Millers  River,  the  broad  Montague  plain. 

The  low  lake  bottom  in  Hatfield,  made  up  as  it  is  of  very  fine  sands, 
is  also  greatly  affected  by  old  dunes,  and  many  of  the  scattered  farm 
buildings  are  here  built  upon  dunes,  while  a  line  of  still  moving  sand  drifts 
runs  up  through  the  center  of  the  plain,  and  is  indicated  on  the  map. 

But  the  most  remarkable  exhibition  of  dunes  in  the  valley  is  where 
the  prevalent  westerly  winds  strike  the  scarp  which,  on  the  east  side  of  the 
river,  separates  the  flood  plain  of  the  Connecticut  from  the  lake  bottom. 
This  sharp,  westward-facing  scarp  has  been  longest  exposed  to  the  winds, 
and  is  made  up  of  very  fine  sands,  and  taking  the  eastern  of  the  roads 
which  runs  from  Sunderland  to  North  Hadley,  one  crosses  an  almost  con- 
tinuous line  of  great  sand  drifts  until  this  road  joins  the  next  westerly  one, 
and  the  line  of  dunes  is  continued  southwai'd,  and  along  the  west  side  of 
Mount  Warner  has  pushed  high  up  the  side  of  the  hill.  Farther  south  the 
scarp  is  notched  in  many  places  by  old  or  still  active  dunes,  one  of  which 
is  in  sight  on  the  south  side  of  the  road  from  Amherst  to  Northampton, 
just  before  it  enters  Hadley. 

Wind  loess. — All  along  the  west  slope  of  the  Amherst  ridge,  especially 
opposite  the  lower  openings  in  the  ridge,  as  across  the  old  cemetery  or  south 
of  College  Hill,  a  layer  of  fine  unstratified  loam  or  loess  has  been  brought 
by  the  prevailing  westerly  winds  from  the  broad  lake  bottom  of  fine  sand 
which  extends  west  from  the  bottom  of  the  ridge.  This  layer  is  from  2  to 
2  J  feet  thick,  and  extends  over  the  whole  ridge,  resting  on  the  shore  sands 
and  gravels,  and  higher  up  on  the  till,  and  extends  for  a  long  distance 
down  over  the  east  slope.  I  have  traced  it  everywhere  over  the  ridge  in 
the  network  of  cuttings  for  the  gas  and  water  pipes,  the  sewers,  and  the 

'  See  PI.  XXXV,  in  pocket  at  end  of  volume 

=  Geology  of  Massachusetts,  p.  130;  Jour.  Boston  Soc.  Nat.  Hist.,  Vol.  I,  p.  80. 

3  Geology  of  Massachusetts,  Final  Report,  p.  326. 


MINEIIAL  SPRINGS.  749 

railroad,  ami  found  it  present  in  every  undisturbed  opening'.  It  was  espe- 
cially  well  marked  in  the  ditches  dug  across  the  Agricultural  College  farm 
iu  1896  for  laying  water  pipes. 

MINERAL,   SPRINGS. 

The  noteworthy  springs  in  the  region  may  be  classified  as  follows: 

1.  Springs  fro^n  the  gneiss.  In  Shutesbury,  just  west  of  the  village,  is  a 
spring  which  was  discovered  about  1808,  and  a  hotel  was  built  at  the  place, 
which  is  still  called  the  Pool  Tavern,  although  it  has  long  been  used  as  a 
private  house  and  the  well  dug  over  the  spring  has  caved  in.-^ 

More  celebrated  are  the  "Orient  Springs,"  in  Pelham,  so  named  by 
President  Hitchcock.  These  springs  rise  on  the  strong  transverse  fault 
which  crosses  Pelham  and  Prescott.  The  large  building  built  at  the  spring 
in  1861  was  never  a  success,  and  it  was  burned  in  1883.  It  is  a  quite 
strong  sulphur  spring. 

2.  Springs  from  the  mica-schist.  The  abundant  pyrite  in  these  schists 
has  everywhere  produced  springs  which  are  strongly  mineralized.  In 
Amherst,  especially  along  the  west  of  the  ridge,  where  the  schists  come 
near  the  surface,  many  wells  contain  so  much  copperas  that  the  waters 
blacken  tea  and  curdle  milk. 

In  Hawley  the  Moody  Spring,  in  the  southwest  part  of  the  town,  is 
said  to  possess  strong  medicinal  properties  and  to  be  a  specific  for  salt- 
rheum  and  other  cutaneous  diseases  A  similar  chalybeate  spring  in  the 
southern  part  of  Ashfield  has  a  local  reputation. 

The  Mount  Mineral  Spring,  Shutesbury,  was  known  as  a  chalybeate 
spring  as  early  as  1828.^  The  Mount  Mineral  Spring  Company  was  incor- 
porated in  1867.  A  fine  hotel  was  sustained  for  some  years,  but  burned  in 
1876,  and  the  property  has  since  been  abandoned.  Appended  is  an  analysis 
of  the  water,  furnished  me  by  the  present  owner  of  the  property.  It  is  a 
pure  alkaline  chalybeate  water  containing  manganese  in  solution. 

'Evert's  History  of  Connecticut  Valley  in  Massachusetts,  Vol.  II,  p.  758. 
2  E.  Hitchoook,  Am.  Jour.  Sol.,  1st  series,  vol.  13,  1828,  p.  217. 


750 


GEOLOaT  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 


Analysis  by  S.  Dana  Hayes  of  water  of  Mount  Mineral  Spring;  in  one  United  States 
gallon  of  231  cubic  inches;  June  14,  1878. 


Sulph.  pot 

Snlph.  lime 

Clilor.  soda 

Bicarb. soda 

Bicarb,  lime 

Carb.  and  crenate  of  iron. 

Carb.  mang 

Alumina 

Silicic  acid  in  solution 


Total. 


Parts  per 
100,000. 


1,476 
301 
3,360 
1,398 
2,351 
5,537 
364 


701 


15, 488 


Grams. 


0.868 

.175 
1.949 

.811 
1.364 
3.108 

.223 
trace 

.407 


8.905 


3.  Water  of  artesian  wells  in  the  Triassic.  All  the  artesian  wells  dug 
in  the  valley  have  much  saline  matter  in  solution.  I  was  informed  by 
Prof.  C.  U.  Shepard,  as  the  result  of  his  analysis  of  the  water  of  the  South 
Hadley  well,  that  common  salt  was  present  in  large  amount,  and  the  abun- 
,  dance  of  the  salt  pseudomorphs  in  the  sandstones  in  which  the  well  was 
bored  indicates  that  this  comes  from  the  sea  water  entangled  in  the  sand- 
stones at  the  time  of  their  deposition.  The  appended  analysis  of  a  sample 
from  the  more  northern  well  shows  that  the  water  has  nearly  the  constitution 
of  a  bittern.  One  United  States  gallon  of  water  contained  in  solution  102.54 
grains  of  saline  matter,  which  consisted  of  the  substances  named  below. 

Analysis  by  Prof.  G.  A.  Goessmann  of  one  gallon  of  water  from  the  artesian  well  at  the 
Montague  Paper  Company's  mills  at  Turners  Falls,  Massachusetts;  made  at 
Amherst,  November  2,  1874. 


Potasaa 

Soda 

Magnesia 

Lime 

Chlorin 

Sulphuric  acid 
Silicon 

Total  ... 


G-raina. 


0.352 
2.994 
3.690 

36.  951 
.363 

58. 191 
trace 


102. 541 


MINERAL  SPKINGS. 


751 


4.  Sprhii/s  of  the  fjhicinl  hikes  in  the  iijildi/rls. — Rpriiig's  rising  from  tlie 
baso  *>t'  till.'  liravy  sands  of  glacial  lakes  in  the  uplands  rest  oia  the  till,  and 
those  from  the  base  of  similar  sands  of  the  Connecticut  Lake  rest  on  the 
Chami)lain  clays.  These  are  hardly  to  be  called  mineral  springs.  The 
former  furnish  the  sources'  of  many  of  our  mountain  brooks.  The  latter, 
K'ing  nearer  the  villages,  are  better  known.  Of  these  are  the  slightly 
chalybeate  spring  at  South  Hadley  Falls,  the  fine,  strong  spring  which 
gushes  out  of  the  blufi"  west  of  Hatfield  village,  and  several  issuing  from 
the  bluffs  that  surround  Deerfield.  In  Springfield  the  Wesson  Spring, 
Avhich  supplies  the  water  of  Court  Square  and  a  fountain  at  the  corner  of 
Willow  and  Stockbridge  streets;  the  Walker  Spring,  at  the  corner  of  Maple 
and  Stockbridge  streets,  and  the  Ingersoll  Grrove  Spring,  a  hundred  feet 
south  of  Dartmouth  terrace,  the  water  of  which  is  sold  largely  in  the  city, 
are  of  this  character.  The  rain  waters  which  have  fallen  upon  the  surface 
of  the  high  terrace  on  which  the  higher  portion  of  the  city  is  built  sink 
through  these  sands  to  the  horizontal  and  impervious  surface  of  the  clays 
beneath  and  emerge  at  the  edge  of  the  blufi". 

The  Ingersoll  Grove  Spring  was  reported  upon  by  the  State  board  of 
health,^  and  the  result  of  its  analysis  is  given  below  (I)  in  connection  with 
the  analysis  (II)  in  the  same  pamphlet  of  the  Massasoit  Spring,  described 
below.  The  Massasoit  Spring  is  of  ideal  purity;  the  other  gives  plain  indi- 
cation of  the  presence  of  the  barn,  sewer,  and  streets,  which  are  reported  in 
the  immediate  vicinity  of  the  spring. 

Analyses  of  waters  of  Ingersoll  Grove  and  Massasoit  springs. 
[Parts  in  100,000.] 


I.  Ingersoll  Grove. 

II.  Massasoit. 

liesidue  on  evaporation 

8.70 

.000 

.0008 

.43 

.5000 
.0002 
.0275 
2.73 
.0 

5.50 

.000 
.000 
.09 

.0600 
.0001 
.0160 
2.86 
.0 

Ammonia : 

Free  .                                  

Nitrogen  as — 

Nitrates                                             - .  - 

Nitrites                                         

Oxygen  consumed                        

Hardness .            

1  Examination  of  spring  waters  ofifered  for  sale  in  Massachusetts  :  Twenty-third  A.nn.  Eept. 
State  board  of  health,  pub.  doc.  34,  1891  (also  separate  publication),  pp.  356,  362,  364. 


752 


GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 


The  Massasoit  Spring-  on  the  "Bear  Hole"  farm,  in  the  western  part  of 
West  Springfield,  issues  from  the  base  of  a  very  high  bluff  of  sand  that 
forms  the  east  wall  of  the  deep  channel  which  the  Black  Brook  has  cut  in 
the  broad  sand  plain.  The  spring  is  said  to  show  the  uniform  temperature 
of  45°  F.  tln-oughout  the  year.  An  analysis  by  Prof  Charles  Mayr,  pub- 
lished in  the  pamphlet  advertisement  of  the  spring,  is  here  given: 

Analysis  of  icater  of  Massasoit  Spring. 


Grains  in 
1,000,000. 

Grains  in 
1  gallon. 

Sodium  chloride  (salt) 

6.0 

23.0 

8.0 

4.2 

4.0 

12.0 

trace 

0.360 

1.380 
.480 
.252 

9.240 
.720 

trace 

Silica 

Organic  substances .  . 

Potash,  iron,  alurnina,  phosphates,  nitrates 

Total 

57.2 

3.432 

Although  the  spring  was  discovered  only  in  1886,  very  attractive 
buildings  have  been  erected  and  it  has  become  a  well-known  place  of 
summer  resort,  and  the  water  has  been  put  on  sale  in  Springfield  for  table 
use.  The  brook  just  to  the  west  runs  over  the  surface  of  the  trap,  which 
dips  with  great  thickness  beneath  the  sands  from  which  the  springs  flow, 
but  it  is  not  probable  that  a  deep-seated  water  coming  up  through  the 
sandstone  and  trap  would  be  so  pm-e.  It  is  probable  that  the  waters 
come  wholly  from  the  sand  itself,  and  that  the  exceptional  purity  comes 
from  the  fact  that  they  have  been  filtered  through  a  hundred  feet  of  this 
sand. 


THICK  MODERIf  FISSURE  DEPOSITS   OP   QUARTZ  SURROUNDING 
ROOTS  IK  THE  BASE   OF  THE   HOLXOKE   TRAP  SHEET. 

In  1891  a  great  block  of  the  trap  fell  from  the  vertical  wall  at  the  point 
on  the  river  above  Titans  Pier,  where  the  trap  contains  limestone,  and  dis- 
closed a  mass  of  translucent  chalcedonic  quartz  nearly  as  large  as  a  man's 
head,  which  was  pierced  with  tubular  openings  0.5  to  1  ™™  in  diameter  and 
at  least  4  inches  in  length,  generally  nearly  but  not  rigidly  parallel,  and  so 


PISSUEE  DEPOSITS  OP  QUARTZ,  753 

closely  gi'ouped  that  the  separating  walls  of  silica  were  quite  tliiu  or  partly 
wanting.  At  times  they  Avere  quite  wide  apart  or  in  small  groups.  These 
tubes  are  lined  with  limonite  and  sometimes  nearly  tilled  with  it.  At  times 
a  separate  cylinder  or  open  tube  of  limonite  is  found  free  in  the  cavities. 
The  limonite  can  not  be  wholly  removed  from  the  cavity,  but  impregnates 
the  silica  ft)r  a  small  but  definite  distance  in  from  the  surface  of  the  cavity. 

The  most  striking  circumstance  is  that  the  silica  in  one  portion  of  the 
mass  grades  with  imperceptible  boundary  into  a  mass  of  distinctly  banded, 
siliceous,  dove-colored  limestone,  or  ankerite,  as  it  oxidizes  into  a  porous 
ocher. 

It  seems  tolerably  clear  that  the  general  explanation  of  this  must  be 
that  a  mass  of  rootlets  penetrating  a  fissure  of  the  trap  became  coated  with 
limonite  and  that  then  a  deposit  of  silica,  at  first  impregnating  the  limonite 
there,  went  on  to  fill  the  whole  fissure,  while  in  part  of  the  latter  a  mixture 
of  calcite  and  silica  completed  the  work.  Where  the  delicate  cylinders  and 
tubes  of  limonite  rest  free  in  the  cavity  we  may  suppose  that  limonite  was 
deposited  within  the  bark  of  the  rootlet,  replacing  or  surrounding  the 
shrunken  pith.  Indeed,  a  portion  of  this  bark  remained  in  the  tube  at  one 
place  and  was  in  part  removed  and  burned. 

MON  XXIX 48 


OHAPTEE    XXII. 

SUPPLEMENT    TO    THE    AUTHOR'S    MINERAL   LEXICON   OF 
FRANKLIN,    HAMPSHIRE,   AND    HAMPDEN   COUNTIES.^ 

1895.  Albite.     Blandford;  Osborn's  soapstone  quarry. 

Fire,  fresh,  white-translucent  crystals  an  inch  across.  In  flat  plates  from 
growth  in  fissures  and  large  development  of  basal  plane,  which  is  deeply  striate 
parallel  to  the  intersection  edges  with  the  primary  prism. 

Twinned  by  the  pericline  law  and  with  few  plates  interposed  according  to 
the  albite  law. 

Forms  present,  b  (010),  c  (001),  m  (110),  //  (450),  /  (130),  C  (150),  M  (110),  v  (450), 
z  (130),  X  (101),  y  (112),  e  (021),  p  (111),  o  (111).    (See  p.  85.) 

1896.  Albite.     Chester. 

At  the  adit  of  the  new  mine  opened  north  of  the  road  opposite  the  old 
Emery  mine.  The  mineral  occurs  in  perfect  simple  white  crystals  an  inch 
in  leugth.    They  inclose  titanite  and  are  coated  with  prochlorite. 

1892.  Allanite.     Belchertown. 

Cited  from  Belchertown.     E.  S.  Dana.     Sys.  Min.,  p.  1058. 

1892.  Ankerite.     Middlefield. 

E.  S.  Dana.     Sys.  Min.     Localities,  p.  1059. 

Doubtless  from  the  steatite  bed.  All  the  specimens  I  have  examined  from 
these  beds  were  dolomite. 

1892.  Anthophyllite.     Blandford. 

E.  S.  Dana.    Sys.  Min.,  p.  1058. 

This  is  the  brown  actinolite  from  Osborn's  soapstone  quarry. 

1892.  Anthophyllite.     Chesterfield. 

E.  S.  Dana.     Sys.  Min.,  p.  1058. 

This  is  the  hair-brown,  coarsely  fibrous  mineral  from  the  bluff  above  Burnell's 
pond,  which  is  identical  with  the  cummingtonite  or  amphibole-anthophyllite 
occurring  in  Cummington,  a  little  way  farther  north,  in  the  Conway  schists. 

'  See  Bull.  U.  S.  Gaol.  Survey  No.  126,  1895. 
754 


SUPPLEMENT  TO  MINERAL  LEXICON.  755 

1892    Antiiophyllite.     Chesterfield. 

E.  S.  Dana.    Sys.  Min.    Localities,  p.  1058. 

I  have  never  found  tliis  mineral  in  Chesterfield,  nor  any  of  the  minerals  with 
wliich  it  is  associated;  nor  do  I  recall  any  other  citation  of  the  mineral  from 
this  town.  I  suppose  it  to  be  the  brown  cummingtonite  from  the  bluffs  west  of 
liuruell's  pond. 

1858.  Anthophyllite.     Enfield. 

Specimens  labeled  "anthophyllite  gneiss"  in  the  State  collection. 
E.  Hitchcock,  Nos.  96, 97,  under  gneiss.    Oat.  State  Col.  Mass.  Agr.  Kept.,  p.  15. 
A  dark-brown,  bladed  mineral.    The  powdered  fragments  all  extinguish  lon- 
gitudinally, as  if  it  were  a  rhombic  mineral. 

1895.  Anthracite.     Holyoke. 

In  Chicopee  shale  of  Triassic  age  below  the  Holyoke  dam.  In  thick  masses 
coating  siderite.  It  has  rounded  surfaces,  showing  that  it  was  introduced  into 
the  fissure  as  a  bitumen.  It  is  in  very  brittle  layers,  which  give  a  yellow  flame 
for  an  instant  and  then  glow  without  further  flame.     (See  p.  370.) 

1896.  Apatite.     Blandford. 

Occurs  in  the  Osborn  soapstone  quarry,  in  rich,  deep  oil-green  crystals  an 
inch  long,  iutercrystallized  with  chlorite.     (See  p.  85.) 

1895.  Apatite.     Chester. 

Crystals  1  to  3"™  in  length  occur  on  and  in  the  diaspore.     (See  p.  143.) 

1895.  Aeagonite.     Chester. 

A  beautiftil  fibrous  satin  spar  occurs  in  the  serpentine  at  the  old  mine,  in 
sheets  a  foot  square  and  IJ  inches  thick.     (See  p.  143.) 

1895.  Barite.     Holyoke. 

Cavities  4  inches  long  and  one-third  inch  wide  and  an  inch  deep,  with  rec- 
tangular ends  or  ends  beveled  like  barite  crystals,  occur  in  the  Chicopee  shale 
below  the  Holyoke  dam.     (See  p.  370.) 

1892.  Bastite.     Westfield. 

B.  S.  Dana.    Sys.  Min.    Localities,  p.  1060.    Cited  as  Schiller  Spar  (Diallage). 
This  is  a  bastite  derived  from  enstatite,  from  Munns  Brook. 

1818.  Beryl.     Emerald.     Chesterfield,  Goshen,  Northampton. 

Chesterfield  furnishes  them  in  great  abundance,  from  the  weight  of  an  ounce, 
or  less,  to  six  pounds.  Hexagonal  prisms;  diameter  sometimes  twelve  inches; 
light  green  (Waterhouse).  Northampton  and  Goshen  (Hunt).  All  coarse 
granitic  beryl. 

Samuel  L.  Mitchill.  Phillips  Mineralogy,  with  additions  on  American  Min- 
erals. 


756 


GEOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 


1892.  Beryl.     Russell,  Warwick. 

E.  S.  Dana.    Sys.  Min.    Localities,  p.  1059. 

1841.  Calcite.     Iceland  Spar.     Wales. 

In  gneiss.    E.  Hitchcock.     Final  Eept.  Geol.  Mass.,  p.  638. 

1897.  Cerdsite.     Hatfield. 

At  the  lead  mine  the  mineral  occurs  in  small  globular  forms,  with  drusy 
surfaces,  and  some  of  the  globules  are  hollow. 

1896.  Clinochlok.     Blandford. 

Broad  encrusting  masses,  3  inches  thick,  of  a  uniaxial  chlorite,  which  is 
granular  at  the  base  but  grows  coarser  upward,  and  grades  into  stout  crystals 
one-half  inch  across,  which  project  freely  from  the  surface.  Prom  the  Bland- 
ford  soapstone  quarry,  formerly  Osborn's  quarry.     (See  p.  85.) 

1896.  Corundum.     Emery.     Middlefield. 

Found  one-half  mile  north  of  the  soapstone  quarry  at  0.  Smiths's.  Traced 
north  from  bowlders  by  Dr.  H.  S.  Lucas.  Shows  quite  large  veins  of  blue 
corundum.    (See  p.  81.)     Springfield  Eepublican,  December  12, 1896. 

1897.  Corundum.     Pelliam. 

Crystals  with  perfect  polished  O  face.  Heating  developed  O  cleavage. 
Others  with  polished  prism  faces  deeply  fluted  horizontally  by  the  oscillation  of 
the  unit  pyramid  face.     (See  p.  47.) 

1853.  CuMMiNGTONiTE.     Hornblende.     Cummington. 

Fibrous,  resembling  anthophyllite;  color,  ash-gray;  in  mica-slate. 

Analyses  of  cummingtonite. 


SiOo . 

Ar^O' 

FeO. 

MgO 

MnO 

CaO  . 

Na20 

KjO. 

H^O., 


Per  cent.       Per  cent. 


51.09 

trace 

.95 

32.07 

10.29 

1.50 

.75 

trace 

3.04 


99.69 


50.74 
.89 

33.14 

10.31 
1.77 

trace 
.54 


3.04 


100.  43 


J.  L.  Smith  and  G.  J.  Brush,  Eeexamination  of  American  minerals :  Am.  Jour. 
Sci.,  1st  series,  Vol.  XVI,  1829,  p.  48. 


SUPPLEMENT  TO  MINERAL  LEXICON. 


757 


1892.  CuMMiNGTONiTE.    Ainpliibole-Antliophyllite,  Iron-Magnesium,  Amphi- 
bolo.     Ciunmiug-ton.     Sp.  gr.  =  3.1  to  3.32. 

E.  S.  Dana.     Sys.  Min.,  pp.  390, 395.     Cites  above  analyses. 

1895.   Datolite.     Northampton. 

Delaney's  quarry,  on  railroad  near  north  line  of  Holyoke,  in  Triassic  diabase. 
Discovered  by  liev.  J.  Prevost.  In  a  crushed  zone  in  tlie  diabase  embedded  in 
calcite.  Very  flne  crystals  of  most  brilliaut  luster,  the  largest  nearly  a  half 
inch  across,  and  with  the  slightly  green  tint  which  is  common  in  the  Bergen 
crystals,  but  here  a  little  more  yellow  than  there.  The  forms  are  of  a  type  new 
in  the  valley,  resembling  fig.  1,  with  the  addition  of  the  base,  or  fig.  4,  page  503, 
of  Dana's  Sys.  Min.,  1892,  but  with  e  and  /<  greatly  increased  at  the  expense  of  m 
andw,;  c  is  a  large  composite  face.  The  forms  present  are  c»  P  (110),  J  P  (Il2), 
O  P  (001),  a>  P  00  (100),  f  P  cib  (023),  P  db  (Oil),  ^-  P  (113),  — P  (111),  ^  P  a> 
(102),  — 2  P  2  (121),  — J  P  ^  (102),  ^-  P  CO  (013),  a,  P  cc  (010),  the  last  four  small. 
Specimens  in  the  Smith  and  Amherst  College  cabinets.     (See  p.  470.) 

1895.  Datolite  var.  Botryolite.     Greenfield. 

At  Cheapside,  in  a  new  road  cut  through  the  trap ;  in  white  globular  masses 
in  steam  holes  in  red  trap.     (See  p.  443.) 

1896.  Enstatite.     Grranville. 

The  mineral,  in  large,  square,  colorless  prisms  from  the  large  bed  at  Downey's 
(see  p.  90),  has  been  analyzed  by  Mr.  W.  P,  Hillebrand,  with  the  following  result: 

Analysis  of  enstatite  from  Granville. 


Per  cent. 

SiOj 

54.04 

none 

.52 

.14 

1.51 

3.90 

.23 

.11 

none 

none 

none 

34.40 

V       .08 

.70 
3.07 
none 
1.32 

TiO» 

AI2O3 ^ 

CraOs  .           ..                               

Fe  3  0  3  .           

FeO 

NiO - 

MnO 

CaO 

SrO 

BaO .                                          

MgO 

K2O 

Na^O " 

LiaO 

H2O  below  110°  C                                              

H«0  above  110°  C.                                          

P2O1 

CO.. 

IOCS.  02 

758  GEOLOGY  OP  OLD  HAMPSHIEE  COUNTY,  MASS. 

1892.  Enstatite.     Westfield. 

E.  S.  Dana.  Sys.  Min.  Localities,  p.  1060.  Cited  as  Scapolite.  This  is  the 
enstatite,  or  the  compact  feldspar  associated  with  it,  from  the  serpentine  locality 
on  Munns  Brook.     (See  p.  90.) 

1896.  Epidote.     Hunting-ton,  on  farm  of  W.  L.  Angell. 

In  a  fissure  in  gneiss  associated  with  quartz,  biotite,  albite,  and  calcite.  (Pen- 
field  and  Pirsson.)     Lighter -colored  crystals  bent  and  broken. 

Si02  =  37.99.  AI2O3  =  29.59.  FeOj  =  5.67.  FeO  =  0.53.  MnO  =  0.21. 
OaO  =  23.87.    H2O  =  2.04.    f  sp.  gr.  3-.367.    Contains  minimum  Fe. 

Paces:  u(100),_c(001),  m(llO),  w(2l0),  e(lOl),  i(l02),  r(TOl),  k(012),  o(Oll), 
n(Ill),  g(221),  y(211).  Twins  (100).  Optical  constants  given.  Double  refrac- 
tion diminishes  with  the  iron.  E.  H.  Forbes,  Zeit.  Krys.  u.  Min.,  Vol.  XXVI, 
p.  138. 

1859.  FiBROLiTE.     Palmer. 

Cited  as  cyanite  under  mica-schist  in  catalogue  of  State  collection,  Nos,  216 
and  218.  E.  Hitchcock.  Sixth  Ann.  Eept.  Dept.  Agr.,  p.  14.  This  is  the 
coarse  fibrolite  from  bowlders  which  are  in  place  in  the  schist  area  included  in 
the  Belchertown  tonalite.    (See  p.  243.) 

1892.  GrALENA.     Westhampton. 

E.  S.  Dana.     Sys.  Min.    Localities,  p.  1060.     Not  elsewhere  cited. 

1892.  GrEDRiTE.     Orange;  east  of  North  Orange,  on  the  west  slope  of  Big 

Tully  Mountain 

Wrongly  cited  from  Warwick  in  Mineral  Lexicon  (Bull.  U.  S.  Geol.  Survey 
No.  126),  p.  86. 

1892.  Heulandite.     Chester. 

Dana.     Sys.  Min.    Localities,  p.  1058.     Cited  as  Stilbite.    This  is  cited  from 
"  E.  Emmons,  Mineral  localities:  Am.  Jour.  Sci.,  1st  series,  VoL  VII,  1824,  p.  254. 

Was  recognized  to  be  heulandite  by  Prof  C.  U.  Shepard  from  the  specimens  in 
Emmons's  cabinet.    Boston  Jour.  Phil.,  Vol.  Ill,  p.  608. 

1896.  Lazulite.     Chittenden,  Vermont. 

In  quartz-muscovite  rock.  There  is  a  specimen  in  the  collection  of  Harvard 
University  from  the  above  locality,  where  it  was  found  by  Mr.  C.  H.  Whittle. 
This  is  probably  the  locality  from  which  the  unique  specimen  found  in  Green- 
field came.    See  under  Lazulite,  in  Bull.  U.  S.  Geol.  Survey  No.  126. 

1895.  Olivine  var.  Villaesite.     Blandford. 

At  the  base  of  the  upper  (eastern)  serpentine  bed  at  the  Osborn  soapstone 
quarry,  in  lenticular  remnants  in  the  serpentine  associated  with  some  still 
unchanged  olivine.     (See  p.  85.) 


SUrPLEMENT  TO  MINERAL  LEXICON.  759 

1896.  Pkochlorite.     Chester. 

On  albite  iu  druses  at  adit  north  of  road  at  old  miue,  in  fine,  large  masses. 
(See  p.  143.) 

1734.  Pyrite.     Northampton'?     "Marcasites,"  Pyrites. 

"Fragments  of  greenish  sulphurous  marcasite  from  Mount  Tom  and  Kolyoke, 
each  side  Connecticut  River." — John  Wintlirop,  P.  R.  S.,  Ex.  Vol.  XV,  Journal 
Book  of  Royal  Soc.    Am.  Jour.  Sci.,  Ist  series,  Vol.  XL VII,  1844,  p.  289. 

1892.  Pyrolusite.     WiUiamsburg. 

E.  S.  Dana.     Sys.  Mln.     Localities,  p.  1060. 

1897.  Pyroxene.     Diopsicle.     Bald  Mountain,  Shelburne  Falls,  Massachu- 
setts. 

In  a  dark,  impure  limestone.  The  crystals  are  themselves  full  of  inclosed 
limestone  and  effervesce  strongly.  They  are  in  stout  prisms  up  to  an  inch  and  a 
half  in  length  and  a  half  inch  across,  greenish-white  in  color,  strongly  lustrous 
on  the  prism  faces  and  glossy;  color,  pale  green.  They  are  nearly  square 
prisms  and  recall  the  Canaan  white  pyroxenes.  This  mineral  shows  under  the 
microscope  the  brilliant  colors  and  the  strong  prismatic  cleavage  of  pyroxene, 
and  a  basal  parting  with  many  interposed  twin  laminae.  The  extinction  reaches 
33°.  The  specimen  probably  comes  from  a  limestone  bed  of  the  Conway  schist, 
which  has  been  strongly  and  peculiarly  metamorphosed  by  contact  with  granite. 

1888.  Quartz.     Rose  quartz.     Blandford. 

Abundant  by  roadside  near  E.  H.  Osburn's. 

1892.  Quartz.     Amethyst.     Greenfield. 

The  cavities  in  the  red  diopside-diabase,  described  on  page  443,  from  the  cut 
through  the  trap  ridge  made  for  the  electric  railroad,  contain  small  amethysts  of 
great  beauty,  which  are  inter  penetration  twins  of  model-like  perfection.  The 
twinning  plane  is  O  (0001). 

1897.  Rhodonite.     "Cunningham"  (for  Cummington.) 

Gr.  P.  Merrill.  Stones  for  building  and  decoration,  p.  174.  Cites  Kunz, 
Min.  Rec,  1887. 


760 


GEOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 


1895.  Salt.     Holyoke. 

Small  cavities,  which,  seem  to  be  ilattened  and  slightly  distorted  from  the 
cubical  form,  occur  below  the  Holyoke  dam  in  the  Triassic  Chicopee  shale.  (See 
p.  370.) 

1895.  SiDERiTE.     Holyoke. 

In  trench  below  Holyoke  dam,  on  fissure  surfaces  of  Chicopee  shale  of  Tri- 
assic age ;  broad  surfaces,  coated  with  drusy  crystallization,  crystals  one-fourth 
to  one-half  of  an  inch  across,  yellow-gray  to  warm  reddish- yellow,  with  brilliant 
luster.  Forms  E,  eo  E  2,  in  equal  development,  which  makes  the  attached  crys- 
tals simulate  dodecahedrons,  so  that  they  can  almost  be  taken  for  garnet. 
Followed  by  gypsum  ( '?),  barite,  calcite,  anthracite,  pyrite.     (See  p.  370.) 

1879.  Serpentine.     Picrolite.     Florida. 

Specimen  in  collection  of  Harvard  University. 
Analysis  by  W.  H.  Melville. 

Analyses  of  serpentine. 


Per  cent. 

Per  cent. 

SiO. 

44.22 
J      6.61 
I        .53 

44.22 
]■       7. 91 

Fe^Oa 

Al^Oa 

MgO 

37.54 

.36 

11.26 

37.40 

.36 

11.22 

H2O(100i) 

H2O  (al)ove  100) 

100. 52 

100. 11 

/\ 


M.  E.  Wadsworth,  Proc.  Boston  Soc.  ISat.  His.,  Vol.  XX,  p.  286.     (See  p.  73.) 

1897.  Serpentine.     Variety  picrolite. 

Pelham;  asbestos  mine  at  the  bottom  of  the  large  digging  and  in  the  midst 
of  the  unchanged  olivine  rock.  A  thick  seam  of  a  leek-green  columnar  and 
polished  serpentine,  plainly  produced  by  pressure  and  slipping.  A  thick  layer 
of  slickensided  columnar  serpentine.     (See  p.  47.) 

1825.  Spodumene.     Vicinity  of  Deerfield.     (Groslien  or  Chestei-field.) 

Light  green,  brittle,  exfoliates  with  blowpipe.  Yields  prism  of  100°;  con- 
tains 8  per  cent  lithia.  Found  in  a  collection  of  minerals,  but  precise  locality 
not  known.     George  Bowen,  Proc.  Phil.  Acad.  Sci,,  Vol.  Ill,  p.  285. 

1825.  Spodumene. 

S.  Eobinson.     Oat.  Am.  Min.     Citation  of  above. 

1892.  Spodumene.     Chester. 

E.  S.  Dana.  Sys.  Min,  Localities,  p.  1058.  This  citation  depends  on  the 
doubtful  report  of  the  species  in  Chester,  in  small  quantity  in  granite,  by  C. 
Dewey.    Geology  of  Berkshire:  Am.  Jour.  Sci.,  1st  series, Vol. VIII,  1824,  p.  243. 


SUPPLEMENT  TO  MIJSTEKAL  LEXICON.  761 

1896.  Spodumene.     tloslieu. 

Tslv.  Alvaii  Barnis  writes  me  as  follows  coucerning  the  spodumeue  localities 
ill  tlie  north  part  of  (loslieii,  near  Taylor's  mill,  and  at  Alannings: 

Now  York  parties  have  bcou  at  work  on  the  siiodiiinoiir  matter  for  lithia  lor  the  past  eight 
years,  oil'  and  on.  They  had  iio  dilBculty  in  g('tting  it  into  a  sohition,  but  had  tronhlo  in 
making  the  separation.  They  wrote  me  a  few  days  ago  that  they  had  succeeded  in  doing  it 
all  right  and  wouhl  soon  report  results,  for  which  I  am  still  waiting.  Wo  find  the  spodumene 
in  i>laco  at  two  points,  as  iudioatcd  on  the  map,  one  leading  north  and  south  and  the  other  half 
a  mile  to  the  east,  rnuuiugoast  and  west.     There  seems  to  l>e  au  abundance  of  it. 

1896.  Talc.     Soapstone.     Blandford. 

Reported  from  the  north  end  of  Blair's  pond.  (S.  A.  Bartholemew.)  Also  as 
au  inclosure  in  horubleade-schist  on  the  road  going  north  from  North  Bland- 
ford  past  Bartholemew's  quarry,  100  rods  east  of  the  road  on  the  west  side  of 
Kound  Hill. 

1896.     TiTANiTE.     Chester. 

At  the  new  adit  north  of  the  road  at  the  old  mine,  in  druses  in  and  on  albite, 
and  covered  by  prochlorite ;  wine-yellow;  common  flat  forms,  often  twinned; 
fine  crystals,  S-G™""  long.     (See  p.  143.) 

1852.  Tourmaline.     Chesterfield. 

The  colored  tourmalines  are  rarely  terminated.  A  fine  crystal  is  figured 
having  the  faces  oo  E  2,  cc  E,  O  E,  E,  with  the  basal  plane  making  nearly  the 
whole  termination  of  the  crystal.  0.  U.  Shepard.  Treatise  on  Mineralogy, 
p.  220. 

1896.  Tourmaline.     Huntington. 

A  mile  north  of  Knights ville,  at  the  700-foot  contour,  on  the  east  side  of  the 
river. — A.  Barrus  (private  communication). 

1896.  Tourmaline.     Huntington. 

Beautiful  flattened  tourmalines  occur  in  muscovite  at  the  quarry  in  pegma- 
tite, near  Knightsville. 

1896.  Tourmaline.     Dendritic  Tourmaline.     Northampton. 

In  fissures  in  the  fine-grained  muscovite-biotite-granite  from  the  village  of 
Haydenville ;  an  exquisite,  delicately  traced  dendritic  growth  of  tourmaline. 
The  surfaces  of  the  fissures  are  perfectly  flat,  wholly  fresh,  and  the  rock  for  1  or 
2  millimeters  in  is  whiter  from  the  absence  of  biotite,  while  the  surface  on  which 
the  dendrite  is  has  also  a  slight  excess  of  biotite  in  larger  crystals  than  in  the 
rest  of  the  rock,  and  a  few  brown-red  garnets.     (See  PL  VII,  p.  316.) 

1896.  Zoisite.     Chesterfield. 

The  locality  is  found  by  following  the  brook  which  enters  East  Branch  a  mile 
south  of  Bisbee  mill,  five-eights  of  a  mile  east,  and  then  going  30  rods  south 
into  a  spur  of  the  hill  marked  1455. — A.  Barrus  (private  communication.) 


CHAPTER    XXIII. 

CHRONOLOGICAL  LIST  OF  PUBLICATIONS  UPON  THE  MIN- 
ERALOGY AND  GEOLOGY  OF  FRANKLIN,  HAMPSHIRE,  AND 
HAMPDEN  COUNTIES. 

1734.  Selections  from  an  ancient  catalogue  of  objects  of  natural  history  formed  in 
New  England  more  than  one  hundred  years  ago,  by  John  Winthrop,  P.  E.  S. 
Journal  Book  of  Royal  Society,  vol.  15,  p.  451;  Am.  Jour.  Sci.,  vol.  47, 1844, 
p.  282.  The  paper  was  copied  from  an  ancient  manuscript.  (See  under  Olay- 
stones.) 

1796.  J.  Morse.  The  American  universal  geography,  3d  ed.,  Boston,  p.  410 ;  copper 
ore,  Leverett;  black  lead,  Brimfleld. 

1810.  J.  Morse.    The  American  gazetteer,  2  vols.,  Boston. 

1810.  B.  Silliman.    Particulars  relative  to  the  .lead  mine  near  Northampton  (Mass.). 

Bruce's  Journal,  vol.  1,  p.  63. 

1811.  WUliam  Meade,  M.  D.    A  description  of  several  combinations  of  lead  lately  dis- 

covered at  Northampton.  Addressed  to  the  editor.  Bruce's  Jourrial,  vol. 
1,  p.  149. 

1815.  E.  Hitchcock.     Southampton  lead  mine;  Basaltick  columns  on  Mount  Ilolyoke. 

North  American  Review,  vol.  1,  p.  334. 

1816.  Parker  Cleaveland.    Mineralogy  and  geology.    Boston,  8°. 

1817.  J.  F.  L.  Hausmann.     Kieselspath  von  Chesterfield,  Mass.     Getting  Gelehrte 

Anzeigen,  p.  1401. 

1818.  E.  Hitchcock.    Description  of  Turners  Falls  on  Connecticut  River;  with  sketch 

by  Mrs.  Hitchcock.    Portfolio.     Philadelphia. 
1818.  B.  Hitchcock.    Remarks  on  the  geology  and  mineralogy  of  a  section  of  Massa- 
chusetts on  Connecticut  River,  with  a  part  of  New  Hampshire  and  Vermont; 
12  pages;  dated  October,  1817;  map  in  1st  and  2d  editions  omitted  in  reprint; 
contains  list  of  minerals.    Am.  Jour.  Sci.,  1st  series,  vol.  1,  p.  105. 

1818.  Samuel  L.  Mitchill.    An  elementary  introduction  to  mineralogy,  by  William 

Phillips,  with  notes  and  additions  on  American  minerals,  by  Samuel  L. 
Mitchill,  Professor  of  Mineralogy,  etc.,  in  the  University  of  New  York. 
Cyanite  and  beryl,  from  Hampshire  County. 

1819.  Amos  Eaton.    Account  of  the  strata  perforated  by,  and  of  the  minerals  found 

in,  the  great  adit  to  the  Southampton  lead  mine;  4  pages.    Am.  Jour.  Sci., 
1st  series,  vol.  1,  p.  136. 
1819.  B.  Silliman.    Localities  of  minerals,  etc. ;  "Molybdenais  found  in  Shutesbury 
*     *    *     on  land  of  William  Eaton;"  1  page.    Ibid.,  p.  238. 
762 


LIST  OF  PUBLICATIONS.  763 

1819.  (ieorgo  Gibbs.     On  the  tounniilines  and  other  minerals  found  at  Chesterfield 

and  Goshen,  Mass.;  G  iiagcs.     Am.  Jour.  Sci.,  1st  series,  vol.  1,  p.  346. 
1811).  K.  Hitchcock.    Supplement  to  the  remarks  on  geology,  etc.,  of  a  section  of 
Massachusetts;  3  pages.     Ibid.,  p.  430. 

1820.  Amos  Eaton.    Index  to  geology  of  Northern  States.    12°,     Troy,  N.  Y. 

1820.  Chester  Dewey.     Localities  of  minerals;  3  pages.     Am.  Jour.  Sci.,  1st  series, 

vol.  2,  p.  23G. 

1821.  Stromeyer.    Chemische  Untersuchungen.     Gottingen.     Aalysis  of  Chesterfield 

albite,  p.  307. 
1821.  Dr.  William  Atwater.    Extract  of  letter;   Hill  of  serpentine  In  Westfleld;  1 

page.    Am.  Jour.  Sci.,  1st  series,  vol.  3,  p.  238. 
1821.  Editor's  note.    On  fossil  fish  (Sunderland),  with  catalogue  of  specimens  sent  by 

E.  Hitchcock;  2  pages.    Am.  Jour.  Sci.,  1st  series,  vol.  3,  p.  365. 

1821.  T,  Dwight.    Travels  in  New  England  and  New  York.    8°.    Vol.  1,  pp.  34-35. 

1822.  Editor's  note.     Micaceous  iron;  Northampton  and  Hawley.     Am.  Jour.  Sci., 

1st  series,  vol.  4,  p.  53. 
1822.  Editor's  note.     "This  fluor  spar  is  of  a  grass  or  emerald  green,  a  rare  color  in 

this  country ;  not  found  except  near  Northampton,  by  Dr.  David  Hunt."    Ibid., 

p.  188. 
1822.  Prof.  C.  Dewey.    Miscellaneous  notices  relating  to  American  mineralogy  and 

geology;  Crystallized  steatite  in  Middlefield ;  3  pages.    Ibid.,  p.  274. 
1822.  Parker  Cleaveland.    An  elementary  treatise  on  mineralogy  and  geology;   2d 

edition ;  2  vols. 
1822.  Editor's  note.    Miscellaneous  notices  on  mineralogy;  Adularia,  Brimfield,  Mass. 

(Prof.  Amos  Eaton).    Am.  Jour.  Sci.,  1st  series,  vol.  5,  p.  41. 
1822.  Prof.  Amos  Eaton.     Geological  and  agricultural  report  of  the  region  adjoining 

the  Brie  Canal  (with  profile  of  the  rocks  across  Massachusetts  from  Boston 

to  Northfield,  by  E,  Hitchcock). 
1822.  Prof.  C.  Dewey.    Notice  of  crystallized  steatite  (Middlefield);  1  page.     Am. 

Jour.  Sci.,  1st  series,  vol.  5,  p.  249.     See  Hampshirite  in  Mineral  Lexicon, 

Bull.  U,  S.  Geol.  Survey  No.  126,  p.  91. 

1822.  E.  Hitchcock.    Fluate  of  lime  and  noble  agates  in  Deferfleld.    Ibid.,  p.  407. 

1823.  H.  J.  Brook.     Cleavelandite.    Annals  of  Philosophy,  p.  381. 

1823.  E.  Hitchcock.  A  sketch  of  the  geology,  mineralogy,  and  scenery  of  the  regions 
contiguous  to  the  Eiver  Connecticut;  with  a  geological  map  and  drawings  of 
organic  remains,  and  occasional  botanical  notices.  (Bead  before  the  Amer- 
ican Geological  Society  at  their  sitting,  September  11, 1822.  Part  I,  86  pages; 
section.  Mount  Toby,  pi.  8;  fossils,  pi.  9;  map,  pi.  10.)  Am.  Jour.  Sci.,  1st 
series,  vol.  6,  p.  1. 

1823.  E.  Hitchcock.     Same.    Part  II,  Simple  minerals ;  35  pages.    Ibid.,  p.  201. 

1824.  E.  Hitchcock.    Same.    Part  III,  Scenery.    Ibid.,  vol.  7,  p.  1. 

1824.  E.  Hitchcock.     Same.    Part  IV,  Miscellanies;  1  plate.    Ibid.,  p.  16. 

[The  same  published  separately.    New  Haven.     S.  Converse,  publisher,  1823.] 


764  GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

1824.  Anon.    Hogtootli  spar  from  Williamsburg.     Hampshire  Gazette,  July  14. 

1824.  Prof.  Chester  Dewey.  A  sketch  of  the  geology  and  mineralogy  of  the  -western 
part  of  Massachusetts  and  a  small  part  of  the  adjoining  States;  with  geolog- 
ical map;  60  pages  [contains  many  notes  from  Emmons].     Ibid.,  p.  1. 

1824.  E.  Emmons.  Article  on  minerals  of  Chester,  etc.,  in  Lyceum  of  Nat.  Hist,  of 
Berkshire  Medical  Institute;  published  ("?).  See  Am.  Jour.  Sci.,  1st  series, 
vol.  8,  p.  32. 

1824.  Dr.  William  Meade.  Localities  of  minerals;  Siliceous  oxide  of  manganese,  Ches- 
terfield.   Ibid.,  p.  54. 

1824.  Dr.  Jacob  Porter.  Localities  of  minerals;  Red  oxide  of  titanium,  Cummington; 
Sulphuret  of  molybdena,  Chesterfield.    Ibid.,  p.  58. 

1824.  George  T.  Bowen.  Analysis  of  spodumene  from  the  vicinity  of  Conway,  Mass. 
Jour.  Acad.  Nat.  Sci.,  Phila.,  vol.  3,  p.  284;  Am.  Jour.  Sci.,  1st  series,  vol.  8, 
p.  121. 

1824.  J.  Porter.  Localities  of  minerals;  1  page.  Am.  Jour.  Sci.,  1st  series,  vol.  8, 
p.  233. 

1824.  C.  U.  Shepard.  Localities  of  minerals;  Pelham,  etc.  [First  notice  of  Shay's 
flint.]     Ibid.,  p.  235, 

1824.  Prof.  Chester  Dewey.  Additional  remarks  on  the  geology  of  a  part  of  Mas- 
sachusetts, etc. ;  5  pages.  [First  notice  of  spodumene,  before  called  white 
augite.]     Ibid.,  p.  240. 

1824.  E.  Emmons.  Notice  of  the  granite  veins  and  beds  in  Chester;  3  pages,  1  plate. 
Ibid.,  p.  250. 

1824.  Professor  Dewey.  Additional  notice  of  argentine  [in  Williamsburg].  Ibid,, 
p.  248. 

1824.  C.  U.  Shepard.  Green  feldsijar  associated  with  sappare  and  siliceous  oxide  of 
manganese,  in  Chesterfield.     Ibid.,  p.  251. 

1824.  Jacob  Porter,    Localities  of  minerals.    Ibid.,  p.  252. 

1824.  Dr.  Eben  Emmons.    Miscellaneous  localities.    Ibid.,  p.  254. 

1825.  S.  Robinson,  M.  D.    Catalogue  of  American  minerals,  with  their  localities, 

Boston,  8°. 

1825.  E.  Hitchcock.  Notice  of  several  localities  of  minerals  in  Massachusetts;  spodu- 
mene corrected;  pyrophysalite  in  Goshen;  3  pages.  Am.  Jour.  Sci.,  1st  series, 
vol.  9,  p.  20. 

1825.  C.  U.  Shepard.    Localities  of  minerals.     Ibid.,  p.  47. 

1825,  J.  Porter.    Localities  of  minerals.    Ibid.,  p.  54. 

1825.  A.O.  Hubbard.  Remarks  oti  the  lead  veins  of  Massachusetts  and  glacial  lakes; 
2  pages.    Ibid.,  p.  166. 

1825.  B.  Silliman.  Notice  of  a  mineral  supposed  to  be  phosphate  of  lime  from  Wil- 
liamsburg and  of  the  localities  of  several  other  minerals.     Ibid.,  p.  174, 

1825.  J.  W.  Webster.  Determination  of  chlorophteite  from  Turners  Falls,  from  speci- 
mens sent  by  Dr.  E.  Hitchcock.    Boston  Jour,  of  Phil,  and  Arts,  vol,  2,  p.  610, 

1825.  E.  Hitchcock.     Mineral  localities.    Ibid.,  p.  610. 


LIST  OF  PUBLICATIONS.  765 

1825.  C.  U.  Shepard.     Mineral  localities,  witli  description  of  aiitbophyllite  (=actino- 

lite),  iolito  (=beryl).     Boston  Jour,  of  Phil,  and  Arts,  vol.  2,  p.  .395. 
1825.  O.  U.  Shepard.    Mineral  localities,  with  description  of  spodumene,  beryl,  schiller- 

spar,  heulandito,  hematite,  anthophyllite,  and   zoisite  from  the  Berkshire 

Hills.     Ibid.,  p.  (i07. 
1825.  E.  Hitchcock.    Geological  sketch  of  the  country  on  the  Connecticut  Eiver;- 

map  and  engravings.     Noticed.     Am.  Jour.  Sci.,  vol.  9,  p.  179. 
1825.  E.  Ilitchiiock.    Topaz*  (in  Goshen);  1  page.     Ibid.,  p.  180. 
1825.  C.  U.  Shepard.    Locahties  of  minerals.     Ibid.,  p.  248. 
1825.  F.  .Mohs.    Jlineralogy.    English  edition;    W.  Haidinger,  Edinburgh.     Cites 

American  localities  fully. 

1825.  E.  Emmons.    Carbonate  of  manganese,  Cummington,  Mass.    Am.  Jour.  Sci.,  1st 

series,  vol.  9,  p.  249. 
1S25.  Emerson  Davis.    Localities  of  minerals  (West  Springfield).    Ibid.,  p.  252. 

1826.  E.  Emmons.    Localities  of  minerals  (Chester  and  vicinity).    Ibid.,  vol.  10,  p.  11. 
1826.  Simeon  Coltou.    Localities  of  minerals  (Monson  and  vicinity).    Ibid.,  p.  12. 
1826.  J.    Porter.    Localities    of  minerals   (Plainfleld    and    vicinity);  correction    of 

D wight's  Travels;  house  on  Eouud  Hill  of  soapstone  from  Middlefleld,  not 

Plainfleld.    Ibid.,  p.  18. 
1826.  J.  Finch.    Memoir  of  the  new  or  variegated  sandstone  of  the  United  States. 

[First  suggestion  that  the  Connecticut  Eiver  sandstone  was  the  New  Eed.] 

Ibid.,  p.  209. 
1826.  Emerson  Davis.    Notice  of  rocks  and  minerals  in  Westfleld.    Ibid.,  p.  213. 
1826.  Prof.  J.  W.  Webster.     On  chlorophaeite  from  Gill,  Mass.    Boston  Jour,  of  Phil. 

and  Arts,  vol.  4. 
1826.  E.  Hitchcock.    Chlorophseite  (Gill).    Am.  Jour.  Sci.,  1st  series,  vol.  10,  p.  393. 
1826.  Anon.    Tabular  quartz  at  Palmer,  Mass.    The  Chemist  and  Meteorological 

Journal,  John  E.  Cutting,  editor,  Amherst  Mass.,  vol.  1,  p.  78. 

1826.  Eeport  of  the  commissioners  of  the  State  of  Massachusetts  on  the  routes  of 

canals  from  Boston  Harbor  to  Connecticut  and  Hudson  rivers.  Letters  from 
Prof.  Edward  Hitchcock  and  others,  with  geological  details;  248  pages;  large 
folding  map.    8°. 

1827.  Alanson  Nash.    Notices  of  the  lead  mines  and  veins  of  Hampshire  County, 

Mass.,  and  of  the  geology  and  mineralogy  of  that  region ;  figures  in  text  and 
engraved  map;  33  pages.    Am.  Jour.  Sci.,  1st  series,  vol.  12,  p.  238. 

1827.  Jacob  Porter.    Localities  of  minerals.    Ibid.,  p.  378. 

1828.  E.  Hitchcock.    Miscellaneous  notices  of  minerals,  with  geological  remarks;  16 

pages.    Am.  Jour.  Sci.,  1st  series,  vol.  14,  p.  215. 

1828.  Editor's  note.    Chesterfield  tourmalines.     "Mr.  Clark  designs  to  explore  his 

locality  and  will  be  better  prepared  to  furnish  collectors  of  cabinets  who  may 
visit  him."    Ibid.,  p.  400. 

1829.  Editor's  notice.    Analysis  of  tourmaline  (green,  Chesterfield),  by  Gmelin.    Ibid., 

vol.  16,  p.  389. 
1829.  E.  Hitchcock.    Tin  at  Goshen.    Ibid.,  vol.  16,  p.  188. 


766       GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

1829.  0.  U.  Shepard.  Discovery  of  stanniferous  columbite  in  Massachusetts  (Chester- 
field) ;  8  pages.    Am.  Jour.  Sci.,  1st  series,  vol.  16,  p.  218. 

1829.  A  History  of  Berkshire,  Mass. ;  in  two  parts.    By  "Gentlemen  in  the  county." 

Pittsfteld,  Samuel  W.  Bush. 

1830.  A.  Eaton.    All  primitive  general  strata  below  granular  quartz  are  contempo- 

raneous and  schistose;  2  pages.    Am.  Jour.  Sci.,  1st  series,  vol.  17,  p.  334. 

1831.  J.  Porter.     Localities  of  minerals.     Ibid.,  vol.  20,  p.  170. 

1831.  John  G.  Hales.    Plan  of  the  town  of  Northampton,  in  the  county  of  Hampshire, 

surveyed  under  direction  of  the  selectmen,  January,  1831.  Pendleton's 
Lithography,  Boston. 

1832.  E.  Hitchcock.    Report  on  the  Geology  of  Massachusetts,  examined  under  the 

direction  of  the  Government  of  that  State  during  the  years  1830  and  1831 ; 
Part  I,  The  economic  geology  of  the  State,  with  a  geological  map ;  70  pages. 
Am.  Jour.  Sci.,  1st  series,  vol.  22,  p.  1. 
1832.  Alfred  Smith.     On  the  water  courses  and  the  alluvial  and  rock  formations  of 
the  Connecticut  Eiver  Valley.    Ibid.,  p.  204. 

1832.  E.  Emmons.    Manual  of  mineralogy  and  geology.    2d  edition;  Albany;  12°; 

299  pages.    Am.  Jour.  Sci.,  1st  series,  vol.  24,  p.  397. 

1833.  Editor's  note.    Professor  Hitchcock's  report  of  the  geology  of  Massachusetts 

(chromate  iron,  Blandford;  rotten  stone.  West  Springfield).    Ibid.,  p.  396. 
1833.  E.  Hitchcock.    Report  on  the  geology,  zoology,  and  botany  of  Massachusetts; 

692  pages;  atlas,  19  plates.     (See  1832  above.) 
1835.  C.  U.  Shepard,    Microlite,  a  new  mineral  species;  2  pages.     Am.  Jour.  Sci., 

1st  series,  vol.  27,  p.  361. 
1835.  C.  U.  Shepard.    Treatise  on  mineralogy;  (Part  I,  containing  terminology  and 

characteristics,  1832,  256  pages) ;  Part  II,  in  2  vols..  Description  of  species, 

1835;  vol.  1,  300  pages;  vol.  2,  331  pages;  12°;  New  Haven. 
1835.  E.  Hitchcock.    Report  on  geology,  etc. ;   2d  edition ;  702  pages,  18  plates,  60 

cuts.    (See  1833  above.) 
1835.  Editor's  note.     Soapstone  or  steatite  of  Middlefleld.    Am.  Jour.  Sci.,  1st  series, 

vol.  27,  p.  382. 

1835.  Editor's  note.    Uranite  at  Chesterfield,  Mass.,  described  by  Professor  Shepard. 

Ibid.,  vol.  28,  p.  382. 

1836.  E.  Hitchcock.    Ornithichnology,  or  description  of  the  footmarks  of  birds  (ornith- 

ichnites)  on  New  Red  sandstone  in  Massachusetts;  34  pages,  3  plates.  Ibid., 
vol.  29,  p.  307.    January,  1836. 

1836.  E.  Hitchcock.  Controversy  with  Rev.  Mr.  Chapin,  of  Connecticut,  on  foot- 
marks.   Knickerbocker,  vol.  8,  p.  289.     September,  1836. 

1836.  J.  H.  Redfield.  Fossil  fishes  of  Connecticut  and  Massachusetts,  with  a  notice 
of  an  undescribed  genus.  Annals  of  the  Lyceum  of  Nat.  Hist.,  N.  Y.,  vol.  4, 
p.  35. 

1836.  Editor's  note.  Albite  of  Chesterfield.  Analysis  by  MM.  Aug.  Laurent  and 
Ch.  Holms.    Am.  Jour.  Sci.,  1st  series,  vol.  30,  p.  381. 


LIST  OF  PUBLICATIONS.  767 

18.H7.  1"].  ITitclicock.  Fossil  footsteps  in  sandstone  and  graywacke;  .'5  pages.  Am. 
Jour.  Sci.,  1st  series,  vol.  32,  p.  174. 

1837.  0.  U.  Shepard.    Chemical  examination  of  microlite.     Ibid.,  p.  338. 

183S.  J.  W.  Foster.  New  locality  of  iolite,  with  other  minerals  associated  (Brimfleld); 
2  pages.    Ibid.,  vol.  33,  p.  399. 

1838.  C.  IJ.  Shepard.     Notice  of  a  second  locality  of  topaz  in  Connecticut,  and  of  the 

])heiiakite  in  Massachusetts;  3  jjages.     Ibid.,  vol.  34,  p.  329. 
1S3S.  F.  Hitchcock.    Eeport  on  a  reexamination  of  the  economical  geology  of  Mas- 
sachusetts; 139  pages;  Boston,  Button  &  Wentworth,  State  printers. 

1839.  Editor's  note.     Solid  impressions  and  casts  of  di'ops  of  rain.     Am.  Jour.  Sci., 

1st  series,  vol.  37,  p.  371. 

1840.  E.  Hitchcock.     Elementary  geology.     Amherst.    J.  S.  &  0.  Adams;  12°;  329 

pages. 

1841.  W.  C.  Eedfleld.     Short  notices  of  American  fossil  fishes;  5  pages.     Am.  Jour. 

Sci.,  1st  series,  vol.  41,  p.  24. 

1841.  Mr,  Teschemacher.  On  the  occurrence  of  phosphate  of  uranium  in  the  tourma- 
line in  Chesterfield;  abstract.  Proc.  Boston  Soc.  Nat.  Hist.,  April,  1841,  vol. 
1,  p.  15. 

1841.  E.  Hitchcock.  Final  report  on  tlie  geology  of  Massachusetts ;  in  four  parts : 
1,  Economical  geology;  2,  Scenographical  geology;  3,  Scientific  geology; 
4,  Elementary  geology,  with  an  appended  catalogue  of  the  minerals  and 
rocks  in  the  State  collection ;  by  E.  Hitchcock,  LL.  D. ;  4° ;  831  pages,  55 
plates,  geological  map. 

1841.  H.  I).  Eogers,  L.  Vauuxem,R.  C.  Taylor,  E.  Emmons,  T.  A.  Conrad.  Eeport  on 
the  ornithichnites  or  footmarks  of  extinct  birds  in  the  New  Eed  sandstone  of 
Massachusetts  and  Connecticut,  observed  and  described  by  Professor  Hitch- 
cock, of  Amherst.  Am.  Jour.  Sci.,  October,  1841,  1st  series,  vol.  41,  p.  165. 
The  report  of  a  committee  appointed  by  the  Association  of  American  Geol- 
ogists to  determine  if  the  tracks  described  by  Hitchcock  were  really  tracks 
and  not  imitative  forms. 

1841.  S.Borden.     Account  of  a  trigonometrical  survey  of  Massachusetts.    Trans.  Am. 

Philos.  Soc,  Phila.,  new  series,  vol.  9,  p.  33. 

1842.  J.  E.  Teschemacher  and  A.  A.  Hayes.     On  the  identity  of  pyrochlore  with  the 

microlite  of  Professor  Shepard;  3  pages.  Am.  Jour.  Sci.,  1st  series,  vol.  43, 
p.  33. 

1842.  C.  U.  Shepard.  On  the  want  of  identity  between  microlite  and  pyrochlore;  6 
pages.    Ibid.,  p.  116. 

1842.  C.  TJ.  Shepard.  Washingtonite  and  phenacite  (Goshen).  Additional  notices  of 
the  supposed  phenacite  of  Goshen;  2  pages.    Ibid.,  p.  364. 

1842.  E.  Hitchcock.  On  a  new  species  of  ornithichnite  from  the  valley  of  the  Connect- 
icut Eiver,  and  on  the  raindrop  impressions  from  the  same  locality  (title 
only).    Trans.  Assoc.  Am.  Geol.  Nat.,  vol.  1,  p.  63. 

1842.  William  C.  Eedfield.    Eemarks  on  Sunderland  Triassic  fishes.     Ibid.,  p.  65. 


768        GEOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 

1842.  James  G.  Percival.     Rej)ort  on  the  geology  of  tlie  State  of  Counecticut;  map. 

New  Haveu.     8°. 

1843.  0.  Lyell.     On  the  fossil  footprints  of  birds  and  impressions  of  raindrops  in  the 

valley  of  the  Connecticut  (abstract);  4  pages.    Proc.  Geol.  Soc.  London,  vol. 

3,  p.  274;  also  Am.  Jour.  Sci.,  1st  series,  vol.  45,  p.  394. 
1843.  B.  Silliman.    Ornithichuites  of  the  Connecticut  Eiver  sandstones  and  the  dinor- 

nis  of  New  Zealand  (correspondence  of  Dr.  Deane,  Dr.  Mantell,  and  E.  Owen) ; 

12  pages.    Am.  Jour.  Sci.,  1st  series,  vol.  45,  p.  177. 
1843.  F.  Alger.    Identity  of  lincolnite  and  heulandite;  abstract.     Proc.  Boston  Soc. 

Nat.  Hist.,  vol.  1,  p.  145. 
1843.  J.  E.  Teschemacher.     On  the  occurrence  of  the  phosphate  of  uranium  in  the 

tourmaline  locality  at  Chesterfield.    Jour.  Boston  Soc.  Nat.  Hist.,  vol.  4,  1844, 

p.  35. 
1843.  J.  E.  Teschemacher.     Description  of  the  oxide  of  tin  at  the  tourmaline  locality, 

Chesterfield.    Trans.  Assoc.  Am.  Geol.  Nat.,  vol.  1,  p.  296. 

1843.  E.  Hitchcock.     Descriptionof  five  new  species  of  fossil  footmarks;  10  pp.    Ibid., 

p.  254. 

1844.  James  Deane.     On  the  fossil  footmarks  of  Turners  Falls,  Mass.,  Avith  2  plates;  6 

pages.    Am.  Jour.  Sci.,  1st  series,  vol.  46,  p.  73. 

1844.  A.  A.  Hayes.  Eeexamination  of  microlite  and  pyrochlore;  8  pages.  Ibid., 
p.  158. 

1844.  Francis  Alger.  Beaumontite  and  lincolnite  identical  with  heulandite ;  4  pages. 
Ibid.,  p.  233;  also  in  Jour.  Boston  Soc.  Nat.  Hist.,  vol.  4,  p.  422. 

1844.  J.  E.  Teschemacher.  Mineralogical  notices;  Pyrochlore  (microlite).  Jour.  Bos- 
ton Soc.  Nat.  Hist.,  vol.  4,  p.  501.     Lon.  Edin.  and  Dub.  Philos.  Mag.,  1844. 

1844.  Simeon  Borden.  Topograiahical  map  of  Massachusetts,  compiled  from  astro- 
nomical, trigonometrical,  and  various  local  surveys,  made  by  order  of  the 
legislature. 

1844.  E.  Hitchcock.  Geological  map  of  Massachusetts,  made  by  order  of  the  legis- 
lature; scale  5  miles  to  the  inch  (on  same  sheet  with  maj)  above). 

1844.  E.  Hitchcock.  Geological  map  of  Massachusetts.  Explanation  of  the  newly 
colored  geological  maj)  of  Massachusets;  22  pages;  12°. 

1844.  E.  Hitchcock.  Eeport  on  ichnolithology  or  fossil  footmarks,  with  a  description 
of  several  new  species,  and  the  coprolites  of  birds  from  the  valley  of  Con- 
necticut Eiver,  and  of  a  supposed  footmark  from  the  valley  of  Hudson  Eiver; 
31  pages,  2  plates  (read  before  the  Association  of  American  Geologists  and 
Naturalists  at  Washingtoji,  May  11,  1844).  Am.  Jour.  Sci.,  1st  series,  vol.  47, 
p.  292. 

1844.  O.U.  Shepard.  A  treatise  on  mineralogy;  2d  edition;  12°;  pp.168.  New  Haven. 
(See  first  edition,  1835.) 

1844.  E.  Hitchcock.  Discovery  of  more  native  copper  in  the  town  of  Whately,  la 
Massachusets,  in  the  valley  of  the  Connecticut  Eiver,  with  remarks  upon  its 
origin;  2  pages.     Am.  Jour.  Sci.,  1st  series,  vol.  47,  p.  322. 


LIST  OF  PUBLICATIONS.  769 

18-14.  J.  Uoaiie.     On  the  discovery  of  fossil  footmarks j  9  pages.    Am.  Jour.  Sci.,  1st 

scries,  vol.  IT,  \^.  381. 
1844.  I'j.  Jliti'licock.    Itejoimler  to  the  preceding   article  of  Dr.   Deaiie;    10  pages. 

Ibid.,  p.  390. 
1841.  J.  Deane.     Answer  to  the  "Rejoinder"  of  Professor  Hitchcock;  2  pages.     Ibid., 

p.  399. 
1S44.  E.  Ilitchcock.    Extract  from  letter  respecting  the  liucolnite.     Ibid,,  p.  416. 

1844.  Francis  Alger.    An  elementary  treatise  on  mineralogy.     By  William  Phillips; 

Stlied.;  602  pages;  Boston. 

1845.  K.  Hitt-hcockl    Mount  Holyoke.    Eeport  on  celebration  of  the  opening  of  a 

road  onto  the  mountain.    Franklin  Express,  Vol.  I,  March,  1845. 
1845.  S.  L.  Dana,  M.  D.    Analysis  of  coprolites  from  the  New  Eed  sandstone  formation 

of  New  England,  with  remarks  by  Professor  Hitchcock.    Am.  Jonr.  Sci., 

1st  series,  vol.  48,  p.  46. 
1845.  E.  Hitchcock.    Extract  from  a  letter    *     *    *     on  fossil  footmarks,  lincolnite, 

and  letter  from  E.  Owen  on  great  birds'  nests  of  New  Holland.    Ibid.,  p.  61. 
1845.  J.  Deane.    Description  of  fossil  footprints  in  the  New  Eed  sandstone  of  the 

Connecticut  Yalley;  plate.    Ibid.,  p.  158. 
1845.  C.  U.  Shepard.    Eeply  to  notice  of  mineralogy  with  notice  of  microlite,  goshenite, 

urauite.     Ibid.,  p.  168. 
1845.  J.  E.  Teschemacher.    Eemarks  on  uranium  and  pyrochlore;  reply  to  above  on 

microlite  and  urauite.     Ibid.,  p.  395. 
1845.  J.  Deane.    Notice  of  new  sijecies  of  batrachian  footmarks;  3  pages  and  cut. 

Ibid.,  vol.  49,  p.  79. 
1845.  J.  Deane.    Fossil  footmarks  and  raindrops  (letter).     Ibid.,  p.  213. 
1845,  J.  Deane.    Illustrations  of  fossil  footmarks;  8  pages,  1  cut.    Jour.  Boston  Soc. 

Nat.  Hist.,  vol.  5,  p.  277. 
1845.  J.  Barratt.     On  fossil  footmarks  iu  the  red  sandstone  of  the  Connecticut  Valley, 

Proc.  Assoc.  Am.  Geol.  Nat.,  p.  23. 
1845.  J.  Barratt.    On  the  evidences  of  congelation  in  the  N"ew  Eed  sandstone.    Ibid,, 

p.  26. 

1845.  C.  Lyell.     On  fossil  footsteps  of  birds  on  Connecticut  Eiver.    Hist.  Travels  in 

U.  S.,  vol.  1,  p.  200. 

1846.  Note.    Washingtonite  of  Shepard  =  ilmenite ;   analysis.     Am.  Jour.   Sci.,  2d 

series,  vol.  1,  p.  122. 
1846,  F.  Alger.    Eeaffirms  his  opinion  that  lincolnite  is  heulandite  (abstract).    Proc. 

Boston  Soc.  Nat.  Hist.,  vol.  2,  p.  89. 
1846.  F.  Alger.    Notices  of  new  localities  of  rare  minerals  and  reasons  for  uniting 

several  supposed  distinct  species;  lincolnite  is  heulandite.    Washingtonite 

analysis.    Jour.  Boston  Soc.  Nat.  Hist.,  vol.  5,  p.  297. 
1846,  J.  Barratt.     Sentinel  and  Witness  extra ;  Middletown,  Conn.,  July  3,  1846. 

Geology  of  Middletown  and  vicinity  (reprint  of).     On  the  tracks  of  large 

birds  found  at  Middletown,  Conn.;  by  Joseph  Barratt,  M.  D. 
MON  XXIX 49 


770  GEOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 

1846.  J.  E.  Tescliemaclier.     Damourite  in  Chesterfield.     Proc.  Boston  Soc.  Nat.  Hist., 

vol.  2,  p.  107;  Am.  Jour.  Sci.,  2d  series,  vol.  2,  p.  119. 

1847.  James  Deane.    Notice  of  new  fossil  footprints.     Am.  Jour.  Sci.,  2d  series,  vol.  3? 

p.  74. 
1847.  E.  Hitclicock.    Elementary  geology;  8tli  edition,  enlarged;  361  pages. 
1847.  Editor's  note.     Ornithichnites.    Am.  Jour.  Sci.,  2d  series,  vol.  3,  p.  276, 
1847.  E.  Hitclicock.    Description  of  two  new  species  of  fossil  footmarks  found  in 

Massachusetts  and  Connecticut,  or  of  the  animals  that  made  them;  cuts. 

Ibid.,  vol.  4,  p.  46. 
1847.  J.  Deane.    Eossil  footprints.    Ibid.,  vol.  4,  p.  448. 

1847.  E.  Hitchcock.    On  the  trap  tuff  or  volcanic  grit  of  the  Connecticut  Yalley,  with 

bearings  of  its  history  upon  the  age  of  the  trap  rock  and  sandstone  generally 
in  the  valley.     Ibid.,  p.  199. 

1848.  J.  Deane.    Eossil  footprints  of  a  new  species  of  quadruped.    Ibid.,  vol.  5,  p.  40. 
1848.  B.  Hitchcock.    Eossil  footmarks  of  United  States;  128  pages,  24  plates.    Mem. 

Am.  Acad.  Arts  Sci.,  new  series,  vol.  3,  p.  129. 

1848.  Dexter  Marsh.    Fossil  footprints;  3  pages,  cut.    Am.  Jour.  Sci.,  2d  series,  vol. 

6,  p.  252. 

1849.  J.  Deane.    Illustrations  of  fossil  footprints  of  the  valley  of  the  Connecticut; 

16  pages,  9  plates.    Mem.  Am.  Acad.  Arts  Sci.,  new  series,  vol.  4,  p.  209. 

1850.  J.D.Dana.    Spodumene, Norwich;  mouoclinic.   Am.  Jour.  Sci., 2d  series, vol.  10, 

p.  119. 

1850.  J.  D.  Dana.     Staurotide,  Norwich.     Ibid.,  p.  121.    Was  triphylite. 

1850.  J.  G.  Brush.     On  American  spodumene.    Ibid.,  p.  370. 

1850,  E.  Hitchcock.  On  the  river  terraces  of  the  Co,nnecticut  Eiver,  and  on  the  ero- 
sions of  the  earth's  surface.    Proc.  Am.  Assoc.  Adv.  Sci.,  vol.  2,  p.  148. 

1850.  C.  Hartwell  and  E.  Hitchcock,  jr.  Description  of  certain  mineral  localities, 
chiefly  in  the  northern  part  of  Worcester  and  Franklin  counties  in  Massa- 
chusetts (title).    Ibid.,  j).  159. 

1850.  J.  Deane.  Fossil  footprints  of  Connecticut  Eiver.  Jour.  Acad.  Nat.  Sci.  Phila., 
2d  series,  vol.  2,  p.  71. 

1850.  E.  Hitchcock.  On  terraces  and  ancient  sea  beaches,  especially  those  of  the 
Connecticut  Eiver  and  its  tributaries.  Eep.  Brit.  Assoc,  1850,  p.  87.  Com- 
munications. 

"l850.  E.  Hitchcock.     On  the  erosions  of  the  earth's  surface,  especially  by  rivers. 
Ibid.,  p.  85. 

1850.  William  H.  Gibbs.    An  address  delivered  before  the  literary  association.  Bland- 

ford,  Mass.,  September  21,  1850.     Springfield,  George  O.  Wilson.     Contains 
notes  on  minerals  in  Blandford,  furnished  by  Dr.  Shurtleff,  of  Westfleld. 

1851.  W.  J.  Craw.     Chemical  examination  of  a  phosphate  of  iron,  manganese,  and 

lithia  from  Norwich,  Mass. ;  2  pages.    Am.  Jour.  Sci.,  2d  series,  vol.  11,  p.  99. 
1851.  J.  D.  Dana.     Physical  and  crystallographical  characters  of  the  phosphate  of 
iron,  manganese,  and  lithia  of  Norwich,  Mass. ;  2  pages.    Ibid.,  p.  100. 


LIST  OF  PUBLICATIONS.  771 

1851.  J.I).  I)aiiii(!).  Miiieralogical  notices  No.  III.  Mineral  species  described  by 
Prof.  C.  U.  Shepard,  New  Haven.  Proc.  Am.  Assoc.  Adv.  Sci.,  New  Haven. 
Enmauiti'.     Am.  Jour.  Sci.,  2d  series,  vol.  12,  p.  211. 

1851.  J.  D.  Dana  (?).  On  the  crystallogiaphic  identity  of  eiimauite  and  brookite. 
Am.  Jour.  Sci.,  2d  series,  vol.  12,  p.  397. 

1851.  William  0.  Red  field.     On  tlie  post-Permian  date  of  the  red  sandstone  rocks  of 

New  Jersey  and  the  Connecticut  Valley,  as  sliown  by  their  organic  remains. 
Proc.  Am.  Assoc.  Adv.  Sci.,  vol.  5,  p.  45. 

1852.  J.  E.  Teschemacher.     On  tlie  angles  of  eumanite.    Am.  Jour.  Sci.,  2d  series, 

vol.  i:\  p.  117. 

1852.  E.  Hitchcock.  On  the  terraces  and  sea  beaches  that  have  been  formed  since 
the  drift  period,  especially  those  along  the  Connecticut  Eiver.  Proc.  Am. 
Assoc.  Adv.  Sci.,  vol.  6  (1851),  p.  261. 

1852.  C.  U.  Shepard.    On  the  triplite  (allaudite)  of  Norwich,  Mass.    Ibid.,  p.  234. 

1852.  C.  U.  Shepard.  A  treatise  on  mineralogy;  3d  edition;  451  pages,  488  illus- 
trations. 

1852.  E.  Hitchcock.    On  the  geological  age  of  the  clay  slate  of  the  Connecticut  Val- 

ley in  Massachusetts  and  Vermont.    Proc.  Am.  Assoc.  Adv.  Sci.,  vol.  6  (1851), 
p.  299. 

1853.  Jules  Marcou.    Geological  map  of  the  United  States  and  the  British  Provinces 

of  North  America.    Text  and  profiles. 
1853.  J.  L.  Smith  and  C  T.  Brush.    Eeexamination  of  American  minerals ;  Spodumene ; 

Norwich.    Am.  Jour.  Sci.,  2d  series,  vol.  16,  p.  471. 
1853.  E.  Hitchcock.    Eeport  on  certain  points  in  the  geology  of  Massachusetts ;  Coals, 

ancient  glaciers.    44  pages,  3  plates. 
1853.  E.  Hitchcock.    Eeport  on  soapstone  of  Middlefield,  Mass..  to  Metropolitan  Soap- 
stone  Co.,  of  New  York;  4  pp. 
1853.  E.  Hitchcock.    Eemarks  on  sandstones  and  fossil  footmarks  (abstract).     Proc. 

Boston  Soc.  Nat.  Hist.,  vol.  4,  p.  378. 
1853.  Scientific  intelligence;  Tryphyline,  Norwich.    Am.  Jour.  Sci.,  2d  series,  vol.  15, 

p.  445. 
1853.  Scientific  intelligence.    Triplite  of  Norwich,  Mass. :  reference  to  Shepard  and 

editor's  note.    Ibid.,  p.  445. 

1853.  C.  U.  Shepard.    Triplite,  Norwich.    Proc.  Am.  Assoc.  Adv.  Sci.,  vol.  6,  p.  234. 

1854.  J.  C.  Warren,  M.  D.    Eemarks  on  fossil  impressions  in  the  sandstone  rocks  of 

Connecticut  Eiver ;  54  pages,  1  plate.    Boston. 
1854.  J.  W.  Mallet.    Analysis  of  beryl  from  Goshen.    Am.  Jour.  Sci.,  2d  series,  vol.  17, 

p.  180. 
1854.  J.  W.  Mallet.     On  phosphate  of  iron  and  manganese,  from  Norwich,  Mass.    Ibid., 

vol.  18,  p.  33. 
1854.  W.  B.  Eogers.    Fossils  of  the  New  Bed  sandstone  and  its  relations  to  the  rocks 

of  Virginia  and  North  Carolina.    Proc.  Boston  Soc.  Nat.  Hist.,  vol.  5,  p.  18; 

also  Am.  Jour.  Sci.,  2d  series,  vol.  19,  p.  123. 


772        GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

1854.  T.  T.  Bouv4.  Note  on  Portland  society's  fossil  footprints.  Am.  Jour.  Sci.,  2d 
series,  vol.  19,  p.  37. 

1854.  J.  Wyman.  On  impressions  of  a  doubtful  sixth  toe  in  some  batracliian  foot- 
prints.   Proc.  Boston  Soc.  Nat.  Hist.,  vol.  5,  p.  84. 

1854.  J.  C.  Warren.    Note  on  ripple-marked  slabs  from  Turners  Falls.     Ibid.,  p.  84. 

1854.  J.  C.  Warren.  Note  on  slabs  with  impressions  from  Connecticut  Elver  sand- 
stone.    Ibid.,  p.  209. 

1854.  W.  B.  Eogers.     Note  on  Olathropteris.    Ibid.,  212. 

1854.  C.  T.  Jackson.  Note  on  tail  traces  in  Connecticut  Eiver  sandstone.  Ibid., 
p.  309. 

1854.  T.  T.  Bouve  and  W.  B.  Eogers.     Note  on  plates  prepared  by  Mr.  J.  Deane  for  a 

proposed  work  on  the  fossil  imjiressions  of  the  Connecticut  Valley.    Ibid., 
p.  348. 

1855.  C.  H.  Hitchcock.    Impressions  (chiefly  tracks)  on  alluvial  clay  in  Hadley,  Mass. 

Am.  Jour.  Sci.,  2d  series,  vol.  19,  p.  391. 
1855.  E.  Hitchcock,  jr.     Description  of  a  new  species  of  Olathropteris  discovered  in 

the  Connecticut  Valley  sandstone.     Ibid.,  vol.  20,  p.  22. 
1855.  J.  Wyman.    Notice  of  fossil  bones  from  the  red  sandstone  of  the  Connecticut 

Eiver  Valley,  from  East  Windsor,  Conn. ;  Eeptiliau  sauroid,  but  with  hollow 

bones.     Ibid.,  p.  394. 
1855.  E.  Hitchcock.     Bones  and  tracks  from  Connecticut  Eiver  sandstone.    Ibid., 

p.  416. 
1855.  W.  B.  Eogers.     On  the  age  of  the  so-called  New  Red  sandstones  of  the  United 

States.     Proc.  Am.  Assoc.  Adv.  Sci.,  vol.  8,  p.  290. 
1855.  James  Hall.    Eed  sandstone  of  the  Connecticut  Eiver  Valley  and  the  proofs  of 

its  Oolitic  or  Liassic  age.     Ibid.,  p.  290. 
1855.  E.  Hitchcock.     Description  of  several  sections  measured  across  the  sandstone 

and  trap  of  the  Connecticut  Eiver  Valley  in  Massachusetts.     Ibid.,  vol.  9, 

p.  225. 

1855.  E.  Hitchcock.     Additional  facts  respecting  the  tracks  of  Otozoum  moodii  on 

the  Liassic  sandstone  of  the  Connecticut  Valley.     Ibid.,  p.  228. 

1856.  E.  Hitchcock.     Discovery  of  a  new  species  of  fossil  fish  and  fossil  footmarks 

from  the  sandstone  of  Turners  Falls.     Am.  Jour.  Sci.,  2d  series,  vol.  21,  p.  97. 

1856.  E.  Hitchcock,  jr.  A  new  fossil  shell  in  Connecticut  Eiver  sandstone.  Ibid., 
vol.  22,  p.  239. 

1856.  W.  C.  Eedfleld.  On  the  relations  of  the  fossil  fishes  of  the  sandstone  of  Connect- 
icut and  other  Atlantic  States  to  the  Liassic  and  Oolite  periods  (name 
"  Newark  Group  "  proposed  for  the  Triassic  sandstones  of  Alleghany  slope). 
Ibid.,  p.  357;  also  Proc.  Am.  Assoc.  Adv.  Sci.,  Part  II,  vol.  10,  j).  180. 

1856.  B.  Hitchcock.  Description  of  a  large  bowlder  in  the  drift  of  Amherst,  Mass., 
with  parallel  striae  on  four  sides.    Am.  Jour.  Sci.,  2d  series^  vol.  22,  p.  397. 

1856.  E.  Hitchcock.  Illustrations  of  surface  geology;  155  pages,  12  plates.  Smith- 
sonian Contributions,  vol.  9.     Second  edition  published  in  1860. 


LIST  OF  PUBLICATIONS.  773 

1856.  Roswell  Field.    Note  on  the  new  web-footed  species  of  track.     Proc.  Boston 

Soc.  Nat.  Hist.,  vol.  6,  p.  10. 
1856.  J.  C.  AViii-ren,  M.  1),     On  jiew  and  renuirkable  gigantic  fossils  and  footmarlvS 

(read    before   Boston    Society  of  Natural   History;   vol.  5,   j).   298).     Daily 

Traveller,  January  24. 
1856.  E.  Ililclicock.     Additional  facts  concerning  tracks  of  Otozoum  moodii  on  Liassic 

sandstone  of  Connecticut  Valley.     Proc.  Am.  Assoc.  Adv.  Sci.,  vol.  9,  p.  228. 

1856.  J.  Deaue.     On  sandstone  fossils  of  Connecticut  Eiver;  6  pages,  3  i>lates.    Jour. 

Acad.  Nat.  Sci.  Pbila.,  2d  series,  vol  3,  p.  173. 

1857.  J.  W.  Mallet.    On  the  rose-colored  mica  of  Goshen.     Am.  Jour.  Sci.,  2d  series, 

vol.  23,  p.  180. 
1S57.  E.Hitchcock.    Tadpoles' nests;  argument  from  number  of  jihalanges  as  to  bird 

nature  of  Triassic  animals.     Proc.  Boston  Soc.  Nat.  Hist.,  vol.  G,  p.  111. 
1857.  H.  F.  Walling.    Map  of  Hampden  County,  Mass.,  based  ui^on  the  trigonometrical 

survey  of  the  State;  240  rods  to  the  incb. 

1857.  E.  Hitchcock.     Geological  map  of  Hampden  County  (with  the  above). 

1858.  E.  Hitchcock.    Ichnology  of  New  England  (list  of  works  on  ichnology  to  date); 

232  pages,  60  plates;  4°. 

1858.  C.  H.  Hitchcock.  Geological  section  from  Greenfield  to  Cbarlemont,  Mass. 
Proc.  Boston  Soc.  Nat.  Hist.,  vol.  6,  p.  330. 

1858.  H.  F.  Walling.  Map  of  Franklin  County,  Mass.,  based  upon  the  trigonomet- 
rical survey  of  the  State;  240  rods  to  the  inch. 

1858.  E.  Hitchcock.     Geological  map  of  Franklin  County  (with  the  above  map). 

1859.  Dr.  Henry  T.  Bowditch.    Life  and  character  of  Dr.  J.  Deane.    Boston  Medical 

and  Surgical  Journal,  February  7,  1859. 

1859.  Who  described  the  bird  tracks?  Controversy  between  Dr.  Deane  and  Professor 
Hitchcock.  Four-column  article  from  life  and  character  of  Dr.  Deane,  of 
Greenfield,  by  Dr.  Henry  T.  Bowditch.  Springfield  Eepublican,  May  7, 
1859. 

1859.  E.  Hitchcock.  A  half  column  letter  of  Mr.  W.  W.  Draper,  of  Greenfield,  who 
claims  to  be  the  first  discoverer  of  footmarks.     Ibid.,  May  21, 1859. 

1859.  E.  Hitchcock.  Reply  to  Mr.  Bowditch  and  defense  of  claims  to  priority  in  dis- 
covery of  footmarks.  Four  columns,  Springfield  Eepublican,  May  14, 1859;  6 
pages;  8°.    See  Eeminiscences  of  Amherst  College,  p.  388. 

1859.  E.  Hitchcock.    Catalogue  of  geological  specimens  in  the  State  House;  69  pages, 

Appendix  to  Sixth  Annual  Eeport  of  the  State  Board  of  Agriculture. 

1860.  Eoswell  Field.    Ornithichnites,  or  tracks  resembling  those  of  birds.    Am.  Jour. 

Sci.,  2d  series,  vol.  29,  p.  361. 

1860.  E.  Hitchcock.  Illustrations  of  surface  geology.  155  pages,  14  plates ;  4° ;  2d 
edition,  Amherst,  J.  S.  &  C.  Adams;  1st  edition  in  Smithsonian  Contribu- 
tions, vol.  9, 1856. 

1860.  E.  Hitchcock  and  C.  H.  Hitchcock.  Elementary  geology;  31st  edition;  rewrit- 
ten ;  430  pages. 


774       GEOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 

1860.  Eoswell  Field.  Note  on  reptilian  nature  of  tracks.  Proc.  Boston  Soc.  ISTat. 
Hist.,  vol.  7,  p.  316. 

1860.  Eoswell  Field.     Ornithiclinites.    Proc.  Am.  Assoc.  Adv.  Sci.,  vol,  13,  p.  337.    . 

1860.  Henry  F.  Walling.  Map  of  Hampshire  County,  Mass.,  based  upon  the  trigo- 
nometrical survey  of  the  State,  the  details  from  actual  surveys ;  240  rods  to 
the  inch. 

1860.  E.  Hitchcock.    Geological  map  of  Hampshire  County  (with  above  map).     (I 

doubt  if  President  Hitchcock  prepared  this  map.     See  page  408.) 

1861.  J.  Deane.     Ichnographs  from  the  sandstone  of  Connecticut  Eiver.    Boston: 

Little,  Brown  &  Co. 
1861.  E.  Hitchcock,  C.  H.  Hitchcock,  etc.     Eeport  on  geology  of  Vermont;  2  vols.,  4°. 

(Connecticut  Eiver  terraces,  Bernardston,  Shelburne  Falls  section.) 
1861.  E.  Hitchcock.     Eemarks  upon  certain  points  in  ichnology.    Proc.  Am.  Assoc. 

Adv.  Sci.,  vol.  14,  p.  144. 

1861.  E.  Hitchcock.    Additional  facts  respecting  the  Clathropteris  of  Easthampton, 

Mass.     Ibid.,  p.  158. 

1862.  J.  D.  Dana.    Fossil  larvtB  in  Connecticut  Eiver  sandstone.    Am.  Jour.  Sci.,  2d 

series,  vol.  33,  p.  451. 
1862.  G.  J.  Brush.     On  the  occurrence  of  tryphyline  at  Norwich,  Mass.     Ibid.,  vol. 

34,  p.  402. 
1862.  E.  Hitchcock.     Supplement  to  the  ichnology  of  New  England.     Proc.  Am. 

Acad.  Arts  and  Sci.,  vol.  6,  p.  85. 

1862.  E.  Hitchcock.    Postscript  to  above.    Ibid.,  p.  104. 

1863.  E.  Hitchcock.    New  facts  and  conclusions  respecting  the  fossil  footmarks  in 

the  Connecticut  Eiver  Valley.     Am.  Jour.  Sci.,  2d  series,  vol.  36,  p.  46. 
1863.  E.Hitchcock.    Eeminiscences  of  Amherst  College;  412  pages;  8°.     Geological 
map  of  Amherst  and  vicinity. 

1863.  C.  T.  Jackson  and  Charles  S.  Eichardson.    Manhan  Silver-Ijead  Mining  Com- 

pany, Hampshire  County,  Mass.  *  *  *  Geological  surveys  and  reports, 
March,  1863.  Boston:  Alfred  Mudge  &  Co.,  printers,  34  School  street;  with 
map.  The  copy  in  the  library  of  Amherst  College  came  from  Dr.  Jackson's 
library,  and  has  his  notes  in  pencil. 

1864.  C.  IT.  Shepard.     Miueralogical  notices;  Tungsten  in  Chesterfield.    Am.  Jour. 

Sci.,  2d  series,  vol.  37,  p.  407. 
1864.  C.  T.  Jackson.     Discovery  of  emery  in  Chester,  Mass.    Proc.  Boston  Soc.  Nat. 
Hist.,  vol.  10,  p.  84. 

1864.  Council  of  American  Academy  of  Arts  and  Sciences.    Obituary  of  President 

E.  Hitchcock.     Proc.  Am.  Acad.  Arts  and  Sci.,  vol.  G,  p.  291. 

1865.  C.  T,  Jackson.    Discovery  of  emery  in  Chester.    Am.  Jour.  Sci.,  2d  series,  vol. 

39,  p.  87. 
1865.  0.    U.    Shepard.    Miueralogical  notices    (Chester,  Whately).    Ibid.,  vol.  40, 

p.  112. 
1865.  C.  TJ.  Shepard.    Miueralogical  notices  (addition  to  Chester,  Whately).     Ibid., 

p.  123. 


LIST  OF  PUBLICATIONS.  ^75 

18«5.   E.  mtcUcock  aud  0.  H.  Hitchcock.     Supplement   to   the  ichnolo.y  of  New 

Kno-laiid:  96  pages,  20  plates;  4°. 
1805.  C.  U.  Shepard.     East  Wl.ately  mine  of  yellow  ocher  and  s.enna;  8  page.;  1.  , 

Amherst,  Mass.,  January  IS,  1805.  ■,      ^       ,. 

U.  Shepar.l.    A  description  of  the  emery  mine  of  Chester,  Hampden  County, 


1865.  C.  U.  Slu'paril 
Mass.,  U.  S 
.  U.  Shepari 
cfij'ipg    vol.  "All  ]}*  -'^^* 
i..^,,.,';     nornndonhilite  of  Shepard.     Ibid.,  p.  394.     (Analysis.) 


Mass    U   S.  A.;  10  pages;  London. 
1866.  C.  U  Shep;'i.     Scheelefine  at  Southampton  lead  mine.    Am.  Jour.  Sc,  2d 


1866   F.Pisani.    Corundophilite  of  Shepard.     ^^^^'^  ^'- ^''-^f^^'i       .. 

860    J  Lawrence  Smith.    On  the  emery  mine  of  Chester.    Ibid    vol.  42,  p  83. 

SfiO    C  T  Jackson     Analysis  of  some  minerals  from  Chester.    Ibid.,  p.  107 
ISOe'  C  U   sCr"i.    Mine'ralogical  notices;  Cotunnite  in  Southampton  lead  mine; 

Colnmbite,  Northfield,  Mass.     Ibid.,  p.  240. 
i«rfi    T  n  THin     Corundophilite  of  C.  U.  Shepard.    Ibid.,  p.  269. 
1800".  C.  U.  She^nd     KoteUncerning  the  minerals  of  the  emery  mine  of  Chester. 

1866  C  Tji^l    Chemical  analyses  of  minerals  associated  with  the  emery  of 

Chester     Proc.  Boston  Soc.  Nat.  Hist.,  voL  10,  p.  320. 

1866.  C.  nlS^hcoc..    Description  of  a  new  reptilian  ^^f^-^^'^^^Zl^^^^^^^ 
sachusetts.     Annals  New  York  Lyceum,   vol.  8,  p.   301.     (Tarsodactylus 

1867  T  7ZZL    Facts  about  peat  as  an  article  of  fuel  (cites  Hitchcock  and  Dr. 

H."  N  Lucas's  experiments  on  mixing  coal  and  peat).    Private  P^bUcation 
1867   C  U  Shepard.     On  the  supposed  tadpole  nests  or  imprints  made  by  the  Batra- 
clfdes  nidiiicans  (Hitchcock)  in  the  red  shale  of  the  New  Eed  sandstone  of 
South  Hadley.    Am.  Jour.  Sci.,  2d  series,  vol.  43,  p.  99. 

1867  J  P  Cooke,  jr.    Clinochlore  from  Chester,  Mass.    Ibid.,  vol.  44,  p.  20b 
1867'.  j'.  D.  dI.'  '  Note  on  the  corundophilite  of  Chester.     Ibid    pp  258  and  283. 

1868  C.U.  Shepard.    Corundophilite  (analysis  by  Eaton).     Ibid  ,  voL  46,  p.  .ob. 
1868   J  D  Dana.    A  system  of  mineralogy;  Descriptive  mmeralogy 

87  :  J.  H.  Adams  (a'member  of  the  class  of  1870,  Amherst  Od  ege).  Jotice  of 
asbestos  and  corundum  with  other  minerals  at  Pelham.    Am.  Jour.  Sci.,  2d 

1870.  E.i"c:;r'o'!\LMlgadactyluspolyzelusof  Hitchcock;  abs^^^^^^^^^^^^ 
in  Transactions  of  American  Philosophical  Society.    Ibid.,  p.  390. 

1870.  C.U.  Shepard.    Mineralogical  contributions  (microlite,  vermicuhte).    Ibid.,  vol. 

1870  C.H.' Hitchcock.    The  geology  of  Vermont;  5  pages;  4°;  privately  printed  as 

part  of  a  proposed  geological  atlas,  but  without  map. 

1871.  J.D.Dana.    On  the  Connecticut  Eiver  Valley  glacier.    Am.  Jour.  Sci.,  3d  series, 

1871  W^H.Nnef  Peculiar  phenomena  observed  in  quarrying  (Monson,  Mass.). 
■       Proc.  Boston  Soc.  Nat.  Hist.,  VOL  14,  p.  80;  also  separate  publication. 


776       GEOLOGY  OP  OLD  HAMPSHIEE  COUNTY,  MASS. 

1871.  A.  A.  Julieii.    Analysis  of  cymatolite.     Am.  Chemist,  vol.  1,  p.  300. 
1871.  H.  F.  Walling  and  O.  W.  Grey.     OfScial  topographical  atlas  of  Massachusetts. 
Stedman,  Brown  &  Lyon,  Boston. 

1871.  C.H.Hitchcock.     "Geological  description"  and  geological  map  of  Massachu- 

setts, in  above  atlas,  p.  17.  The  map  was  so  incorrectly  colored  by  the  pub- 
lishers that  it  was  publicly  repudiated  by  Professor  Hitchcock  at  the  Boston 
meeting  of  the  American  Association  for  the 'Advancement  of  Science. 

1872.  E.  Hitchcock.    Discovery  of  the  tooth  of  a  mastodon  in  Massachusetts  (Cole- 

raine).    Am.  Jour.  Sci.,  3d  series,  vol.  3,  p.  146. 

1873.  J.  D.  Dana.    On  rocks  of  the  Helderberg  era  in  the  valley  of  the  Connecticut, 

the  kinds  including  staurolitic  slate,  hornblendic  rocks,  gneiss,  mica-schist, 
etc.,  besides  fossiliferous  limestone.    Ibid.,  vol.  6,  p.  339. 

1873.  J.D.Dana.  On  the  Glacial  and  Champlaiu  eras  in  New  England.  Ibid.,  vol.  5, 
p.  198. 

1873.  J.  D.  Dana.    Additional  note  to  above.    Ibid.,  p.  217. 

1873.  W.  H.  Niles.  Note  on  movements  of  rocks  in  Monson.  Proc.  Boston  Soc.  Nat. 
Hist.,  vol.  16,  p.  41. 

1873.  H.  P.  Walling.  List  of  lakes,  ponds,  and  reservoirs  in  Massachusetts.  Appen- 
dix B,  Eeport  Massachusetts  State  Board  of  Health. 

1873.  Adolph  Knop.      Studien  liber  Stoffwandlungen  in   Miueralrelche.     Leipzig. 

Serpentine,  p.  50. 

1874.  W.  H.  Niles.     On  some  expansions,  movements,  and  fractures  of  rocks  observed 

at  Monson,  Mass.     Proc.  Am.  Assoc.  Adv.  Sci.,  vol.  22,  Part  II  B,  p.  156. 

1875.  E.  S.  Dana.    Trap  rocks  of  Connecticut  Valley.    Ibid.,  vol.  23,  Part  II  B,  p.  45; 

also  Am,  Jour.  Sci.,  3d  series,  vol.  8,  p.  390. 
1875.  G.  W.  Hawes.    Trap  rocks  of  Connecticut  Yalley  (analysis  of  Holyoke  trap). 

Am.  Jour.  Sci.,  3d  series,  vol.  9,  p.  185. 
1875.  J.  D.  Dana.    On  southern  New  England  during  the  melting  of  the  great  glacier; 

No.  1,  ibid.,  vol.  10,  p.  168;  No.  2,  ibid.,  p.  280;  No.  3,  ibid.,  p.  353;  Sup., 

ibid.,  p.  497. 
1875.  J.  P.  Cooke,  jr.    On  two  new  varieties  of  vermiculites  (pelhamite).     Proc.  Am. 

Acad.  Arts  Sci.,  vol.  10,  p.  453. 
1875.  Report  of  the  water  commissioners  of  the  town  of  Westfleld  on  the  construc- 
tion of  the  waterworks,  including  engineer's  (L.  F.  Root)  report;  50  pages; 

Westfield,  Mass. 

1875.  J.  Hall,  T.  Sterry  Hunt,  Thomas  Doane.     Reports  upon  Hoosac  Tunnel,  with 

profile,  in  report  of  the  corporators  of  the  tunnel.  House  document  No.  9, 
Mass.  legislature. 

1876.  C.  U.  Shepard.     Hermannolite,  a  new  species  of  the  columbium  group.    Am. 

Jour.  Sci.,  3d  series,  vol.  11,  p.  140. 

1876.  J.  D.  Dana.  On  southern  New  England  during  the  melting  of  the  great  glacier. 
Appendix  Am.  Jour.  Sci.,  3d  series,  vol.  12,  p.  125. 

1876.  W.  O.  Crosby.  Report  on  geological  map  of  Massachusetts  prepared  for  Cen- 
tennial Exposition;  52  pages;  8°;  Boston.    Map  not  published. 


LIST  OF  PUBLICATIONS.  777 

187(J    Iteview  of  above.     Am.  .lour.  ScL,  3d  series,  vol.  12,  p.  459.  .       ^      ^     ,       , 

isic   0  U  SbepanL    Oontribatious  to  n,ineval.,,y  (private  pal.licat.on.)     Amherst 

'Coll.-e   Mavll;5pages.     Chester  and  I'elliam  minerals. 
1876    C  U.  Sheiard.    Catalogue  of  minerals  found  within  about  7.5  miles  of  Amherst 

■       Colle-e.    Amherst  College,  May  20;  8  pages;  private  publication. 
1870    W.  H.  Niles.    The  geological  agency  of  lateral  pressure  exhibited  by  certain 

movements  of  rocks.     Proc.  l^oston  Soc.  Nat.  Hist ,  vol.  18,  p^  272 
^7.5    C  H  Hitchcock.    Lenticular  hills  of  glacial  drift.     Ibid.,  vol.  19,  p.  63. 
18;6:  F.  ris^.r  Notices  mineralogiques   (amesite,  euchlorite).     Comptes  Eendus 

Acad.  Sci.  Paris,  vol.  83,  p.  100. 
1877.  J.  D.  Dana.    Note  ou  the  Helderberg  formation  of  Bernardstou.     Am.  Jour. 
Sci.,  3d  series,  vol.  14,  p.  379.  i  iq  ^  or.^.  «pp 

1877.  J.  S.  DiUer.    Westfield  during  the  Champlain  period.    Ibid.,  vol.  13,  p.  ^02,  see 

map.  ^^      ,.    , 

1877.  A.  A.  Julien.    On  aglaite.    Bug.  and  Min.  Journ.,  New  York. 
1877.  C.U.Shepard.     Contributions  to  mineralogy.     Amherst ;  8  pages ;  private  pub- 

1877.  Cn'^^ffitchcock.    Note  upon  the  Connecticut  Yalley  Helderberg.    Am.  Jour. 
Sci.,  3d  series,  vol.  13,  p.  313. 

1877.  C.  H.  Hitchcock.    The  geology  of  New  Hampshire,  vol.  2;  428  pages;  Con- 

1877    J  rDilfer^  Geology  of  Westfield  and  vicinity.     Westfield  Times  and  News- 
'''  Letter  vol  36,  /ebruary  21,  28;  vol.  37,  March  7,  14,  21,  28,  September  19. 

1878.  I.  C.  Eussell.    The  physical  history  of  the  Triassic  formation  of  New  Jersey  and 

the  Connecticut  Valley.    Annals  New  York  Acad.  Sci.,  vol.  1,  pp.  220-254; 
published  separately.  • 

1878.  C.  Doelter.    Ueber  Spodumen  und  Petalit.    Teschermaks  Mm.  Mit.,  n.  s.,  vol.  1, 

1879.  A.  A^  Julien.     On  spodumene  and  its  alterations,  from  the  granite  veins  of 

Hampshire  County,  Mass.    Annals  New  York  Acad.  Sci.,  vol.  1,  p.  318;  1 

plate. 
1879.  Above  reviewed.    Am.  Jour.  Sci.,  3d  series,  vol.  19,  p.  237. 
1879.  A.  A.  Julien.    Composition  of  cymatolite  from  Goshen.     Ibid.,  vol.  17,  p.  39». 
1879    S  L  Penfield.    Chemical  composition  of  triphylite.    Ibid.,  p.  226. 
1879    H  F  Walling.    Some  indications  of  recent  sensitiveness  to  unequal  pressures 

in  the  earth's  crust.     (Contour  map  of  Mount  Toby  and  Sugar  Loaf.)     1  roc. 

Am.  Assoc.  Adv.  Sci.,  vol.  27,  p.  190. 
1879.  Majority  and  minority  reports  of  committee  on  permanent  protection  of  town 

from  future  floods,  with  report  of  Hiram  F.  Mills,  civil  engineer.    Westfield, 

Mass. ;  30  pages.  , 

1879.  Louis  H.  Everts.    History  of  the  Connecticut  Valley  in  Massachusetts.    2  vols, 

Philadelphia.    Many  geological  notes  under  the  town  histories. 

1880.  G.  J.  Brush  and  E.  S.  Dana.     Spodumene  and  the  results  of  its  alteration.    Am. 

Jour.  Sci.,  3d  series,  vol.  20,  p.  257. 


778       GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY,  MASS. 

1881.  C.H.Hitchcock.  Geological  map  of  the  United  States,  with  pamphlet;  map  13 
by  8  feet.     J.  Bien,  'Sevf  York. 

1881.  G.  W.  Hawes.  On  the  mineralogical  composition  of  the  normal  Mesozoic  diabase 
npon  the  Atlantic  border.    Proc.  U.  S.  'Sat.  Mus.,  vol.  4,  p.  129. 

1881.  Chauncey  Stephenson.  Local  geology,  West  Worthington.  Hampshire  Ga- 
zette, November  22,  1881. 

1881.  Chauncey  Stephenson.    Local  geology  No.  2  (emery  and  iron).  West  Worthing- 

ton.   Hampshire  Gazette,  November  29,  1881. 

1882.  J.  D.  Dana.    The  flood  of  the  Connecticut  River  Valley  from  the  melting  of  the 

Quaternary  glacier.    Am.  Jour.  Sci.,  3d  series,  vol.  23,  pp.  87  and  179. 

1882.  B.  K.  Emerson.  The  Deerfleld  dike  and  its  minerals.  Ibid.,  vol.  24,  pp.  195, 
270,  349. 

1882.  W.  M.  Davis.  Triassic  trap  rocks  of  Massachusetts,  Connecticut,  and  New- 
Jersey.    Ibid.,  p.  345. 

1882.  W.  M.  Davis.    The  structural  value  of  the  trap  ridges  of  the  Connecticut  Val- 

ley.   Proc.  Boston  Soc.  Nat.  Hist.,  vol.  22,  p.  116. 

1883.  Albert  Williams,  jr.    Mineral  resources  of  the  United  States,  vol.  1.    U.  S. 

Geol.  Survey. 

1883.  G.  P.  Kunz.  American  gems  and  precious  stones.  Separate  publication  from 
above  work.     (Mineral  resources,  vol.  1.) 

1883.  W.  M.  Davis.  On  the  relation  of  the  Triassic  traps  and  sandstones  of  the  east- 
ern United  States.  Bull.  Mus.  Comp.  Zool.  Harvard  Coll.,  vol.  7  (Geol. 
Series  1),  p.  251;  3  plates  of  sections. 

1883.  R.  P.  Whitfield.  Observations  on  the  fossils  of  the  metamorphic  rocks  of  Ber- 
nardston,  Mass.    Am.  Jour.  Sci.,  3d  series,  vol.  25,  p.  368. 

1883.  G.  H.  Cook.  Annual  Report  of  the  State  Geologist  of  New  Jersey  for  1882. 
Trenton,  N.  J. 

1883.  J.  D.  Dana.  Review  of  above,  including  notes  on  "  The  origin  of  the  Jura- 
Trias  of  eastern  North  America."    Am.  Jour.  Sci.,  3d  series,  vol.  25,  p.  383. 

1883.  J.  D.  Dana.    Western  discharge  of  the  flooded  Connecticut.    Ibid.,  p.  440. 

1883.  J.  D.  Dana.     Phenomena  of   the  Glacial  and  Champlain  periods  about  the 

mouth  of  the  Connecticut  Valley;  that  is,  in  the  New  Haven  region.    Ibid., 
vol.  26,  p.  341. 

1884.  J.  D.  Dana.    Drift  and  terraces.    Papers  on  the  Quaternary  of  New  England, 

from  Am.  Jour.  Sci.,  1871  to  1884,  and  Mem.  Conn.  Acad.,  1870.     (A  small 
edition  of  the  papers  cited  above,  bound  in  a  single  volume.) 

1884.  M.  E.  Wadsworth.    Lithological  studies.    Mem.  Mus.  Comp.  Zool.  Harvard  Coll., 

vol.  11,  p.  1;  4°;  8  plates;  serpentine,  Westfleld,  Mass.  (pi.  7,  fig.  3). 

1885.  Albert  Williams,  jr.    Mineral  resources  of  the  United  States,  vol.  2.    U.  S.  Geol. 

Survey. 
1885.  G.  F.  Kunz.     Precious  stones.     Separate  publication  from  above  work  (Mineral 

resources,  vol.  2). 
1885.  A.  G.  Dana.     On  the  gahnite  of  Rowe,  Mass.    Am.  Jour.  Sci.,  3d  series,  vol.  29, 

p.  455. 


LIST  OP  ITBLIOATIONS.  779 

1885.  G.  P.  MeiTill.  The  collection  of  biiilcling  and  ornamental  stones  in  the 
Uuited  States  National  Museum;  a  handbook  and  catalogue.  Report  Smith- 
sonian Institution,  1S85-C,  Part  II,  pp.  277-648;  Plates  I-IX. 

1885.  Dwiglit  Porter.    Keport  ou  the  water  power  of  the  region  tributary  to  Long 

Island  Sound.    Tenth  Census  U.  S.,  vol.  10. 
1S86.  A.  Williams,  jr.     Mineral  resources  of  the  Uuited  States,  vol.  3.    U.  S.  Geol. 

Survey. 
18S6.  G.  V.  Kunz.    Precious  stones.     Separate  publication  from  above  work  (Mineral 

resources,  vol.  3). 
188G.  Chauncej^  Stephensou.    The  talcose  slate  ledge  in  western  Hampshire  (native 

gold  on  farm  of  Austin  Geer,  in  West  Worthington).    Hampshire  Gazette, 

February  22, 1886. 

1886.  Samuel  H.  Scudder.     The  oldest  known  insect  larva,  Mormolucoides  articulatus, 

from  the  Connecticut  Eiver  rocks.     Mem.  Boston  Soc.  ISTat.  Hist.,  vol.  3,  No.  13, 

p.  431;  40. 
1886.  W.  M.  Davis.    The  structure  of  the  Triassic  formation  of  the  Connecticut  Valley. 

Am.  Jour.  Sci.,  3d  series,  vol.  32,  p.  342. 
1886.  B.  S.  Dana.    Mineralogical  notes;  Columbite,  Northfleld;  Diaspore,  Chester. 

Ibid.,  p.  386. 
1886.  David  T.  Day.    Mineral  resources  of  the  United  States  for  1885;  vol.  3.    U.  S. 

Geol.  Survey. 

1886.  Eaphael  Pumpelly.    Mining  industries  of  the  United  States ;  Corundum,  mica, 

feldspar,  quartz.    Tenth  Census  U.  S.,  vol.  15. 

1887.  B.  K.  Emerson.    Preliminary  notes  on  the  succession  of  the  crystalline  rocks 

and  their  various  degrees  of  metamorphism  in  the  Connecticut  Eiver  region 

(abstract).     Proc.  Am.  Assoc.  Adv.  Sci.,  35th  meeting,  Buffalo,  p.  231 ;  also 

Am.  Jour.  Sci.,  3d  series,  vol.  32,  pp.  323  and  324. 
1887.  B.  K.  Emerson.    The  age  and  cause  of  the  gorges  cut  through  the  trap  ridges 

by  the  Connecticut  and  its  tributaries;  Prelim.  Notes.     Proc.  Am.  Assoc. 

Adv.  Sci.,  p.  232. 
1887.  B.  K.  Emerson.    The  Holyoke  range  of  the  Connecticut.     Ibid.,  p.  233. 
1887.  B.  K.  Emerson.    The  geology  of  Hampshire  County.    W.  B.  Gay,  Syracuse, 

N.  Y.    Chapter  II  in  Gazetteer  of  Hampshire  County;  also  Am.  Jour.  Sci., 

3d  series,  vol.  32,  j).  223.     Section  on  the  Glacial  lake  copied.    Am.  Jour.  Sci., 

3d  series,  vol.  34,  p.  404. 
1887.  N.  S.  Shaler.    Fluviatile  swamps  of  New  England.     Ibid.,  vol.  33,  p.  210. 
1887.  J.  'D.  Dana.    Taconic  rocks  and  stratigraphy,  with  a  geological  map  of  the 

Taconic  region.    Ibid.,  p.  393. 
1887.  David  T.  Day.    Mineral  resources  of  the  United  States,  vol.  4.     U.  S.  Geol. 

Survey. 
1887,  G.  F.  Kunz.     Precious  stones.     Separate  publication  from  above  work  (Mineral 

resources,  vol.  4), 


780       GEOLOGY  OF  OLD  HAMPSHIRE  COUNTY.  MASS. 

1887.  W.  O.  Crosby.    The  elevated  potholes  near  Shelburae  Falls,  Mass.    Technology 

Quarterly,  Boston,  vol.  1,  p.  36. 

1888.  J.  D.  Whitney.     Names   and  places,  studies  in  geological  and  topographical 

nomenclature  (100  copies  printed),  p.  117.  Sugar  Loaf  an  "Eddy-Peak,"  of 
Triassic  sandstone. 

1888.  J.  D.  Dana.  On  the  crystalline  limestone  and  the  conformably  associated 
Taconic  and  other  schists  of  the  Green  Mountains  region.  A  separate  publica- 
tion of  the  author's  papers  upon  this  subject  dated  1873-1882,  with  separate 
title  and  preface. 

1888.  J.  S.  Newberry.  Fauna  and  flora  of  the  Trias  of  New  Jersey  and  the  Connec- 
ticut Valley.  Trans.  N.  Y.  Acad.  Adv.  ScL,  vol.  6;  Eeview,  Am.  Jour.  ScL, 
3d  series,  vol.  36,  p.  70. 

1888.  W.  O.  Crosby  and  Charles  L.  Brown.  Gahnite  from  Rowe,  Mass.  Technology 
Quarterly,  vol.  1,  pp.  407,  408;  also  Am.  Jour.  Sci.,  3d  series,  vol.  36,  p.  167. 

1888.  John  S.  Newberry.  Fossil  fishes  and  fossil  plants  of  New  Jersey  and  the  Con- 
necticut Valley.  Mon.  U.  S.  Geol.  Survey,  vol.  14,  1888;  4°;  96  pages,  26 
plates. 

1888.  O.  Luedecke.     Ueber  Datholit.    Zeitschrift  fiir  Naturwissenschaften,  vol.  61,  p. 

235.    Halle. 

1889.  I.  C.  Eussell.    The  Newark  system.    Am.  Geol.,  vol.  3,  p.  178. 

1889.  C.  H.  Hitchcock.  Eecent  progress  in  ichnology.  Proc.  Boston  Soc.  Nat.  Hist., 
vol.  24,  p.  117. 

1889.  W.  M.  Davis.  The  structure  of  the  Triassic  formation  of  the  Connecticut 
Valley.     Seventh  Ann.  Eept.  U.  S.  Geol.  Survey,  p.  461. 

1889.  W.  M.  Davis.  Topographic  development  of  the  Triassic  formation  of  the  Con- 
necticut Valley.    Am.  Jour.  Sci.,  3d  series,  vol.  37,  p.  423. 

1889.  W.  M.  Davis  and  Chas.  L.  Whittle.     The  intrusive  and  extrusive  Triassic  trap 

sheets  of  the  Connecticut  Valley.  Bull.  Mus.  Comp.  Zool.  Harvard  Coll.,  vol. 
16,  p.  99. 

1890.  B.  K.  Emerson.    Porphyritic  and  gneissoid  granites  iu  Massachusetts  (abstract). 

Bull.  Geol.  Soc.  Am.,  vol.  1,  p.  599. 
1890.  G.  F.  Kuuz.    Gems  and  precious  stones  of  the  United  States.    New  York, 

Scientific  Pub.  Co. 
1890.  B.  K.  Emerson.    A  description  of  the  "Beruardston  Series"  of  metamorphic 

Upper  Devonian  rocks.    Am.  Jour.  Sci.,  3d  series,  vol.  40,  pp.  263  and  362; 

map  and  sections.    Eeview  in  N.  Y.  Independent,  December  4. 
1890.  E.  Nason  and  G.  F.  Varney.    A  Gazetteer  of  the  State  of  Massachusetts.  •  Boston. 
1890.  David  T.  Day.    Mineral  resources  of  the  United  States  for  1888;  vol.  6.    U.  S. 

Geol.  Survey. 
1890.  W.  O.  Crosby.    The  kaolin  in  Blandford,  Mass.;  9  pages.     Technology  Quar- 
terly, vol.  3,  p.  228. 
1890.  Samuel  H.  Scudder.    The  fossil  insects  of  North  America,  with  notes  on  some 

European  species.    2  vols;  4°;  illustrated.    Macmillan  «&  Co.,  New  York. 


LIST  OF  PUBLICATIONS.  781 

1891.  Jules  Miircou.    Biotiiapliical  iiotieo  of  Ebenezer  Eniiiious.    Ami'iician  Geolof^ist, 

vol.  7,  !>.  1. 
1891.   r..  K.   Kmersou.     On  the  Trias  of  Massachusetts,  with  map;  0  pages.     Bull. 

(ieol.  Soc.  Am.,  vol.  2,  p.  4')1. 
1S91.  Ci.  P.  JMui'iill.      Eouks   in   buildiug  and  decoration.      New  York:  J.  Wiley  & 

Sons. 

1891.  H.  S.  Williams.     Correlation  papers.     Devonian  and  Carboniferous.     Bull.  SO, 

U.  S.  (!eol.  Survey. 

1892.  B.  K.  Emerson.     Proofs  that  the  Holyoke  and  Deerfield  trap  sheets  are  con- 

temporaneous flows  and  not  later  intrusions.     Am.  Jour.  Sci.,  3d  series, vol.  iS, 

p.  140. 
1892.  E.  S.  Tarr.     Central  Massachusetts  moraine.    Ibid.,  p.  141. 
1892.  I.  C.  Eussell.     Correlation  papers.    The  Newark  system.    Bull.  85,  U.  S.  Geol. 

Survey. 
1892.  C.  E.  Van  Hise.    Correlation  papers;  Archean  and  Algonkian.    Bull.  86,  U.  S. 

Geol.  Survey. 
1892.  David  T.  Day.    Mineral  resources  of  the  United  States  for  1889  and  1890;  vol.  7. 

U.  S.  Geol.  Survey. 
1892.  Lester  F.  Ward.    The  plant-bearing  deposits  of  the  American  Trias.    Bull. 

Geol.  Soc.  Am.,  vol.  3,  p.  21. 
1892.  J.  D.  Dana.    Additional  observations  on  the  Jura-Trias  trap  of  the  New  Haven 

region.     Am.  Jour.  Sci.,  3d  series,  vol.  44,  j).  165. 
1892.  M.  M.  Mitivier.    New  footprints  from  the.Connecticut  Valley.    Proc.  Am.  Assoc. 

Adv.  Sci.  for  1891,  p.  286. 

1892.  J.   F.   Kemp.     Notes   on  a  granite  from  Chester,  Mass.  [should  be  Becket]. 

Trans.  N.  Y.  Acad.  Sci.,  vol.  11,  p.  129. 

1893.  C.  H.  Hitchcock.     The  Green  Mountains  anticlinal.     Science,  vol.  20,  p.  328. 

1894.  B.  S.  Lyman.     Some  New  Eed  horizons.     Proc.  Am.  Phil.  Soc.  Phila.,  vol.  33, 

p.  192.  Contains  an  extremely  incorrect  geological  map  of  the  Massachusetts 
Trias. 

1894.  E.  Pumpelly,  J.  E.  Wolff,  and  T.  Nelson  Dale.     Geology  of  the  Green  Moun- 

tains in  Massachusetts.  Mon.  U.  S.  Geol.  Survey,  vol.  23;  203  pp.,  4o,  23 
plates. 

1895.  C.  H.  Hitchcock.    The  Connecticut  sandstone  group.      Sustaining  the  above 

name  for  the  Triassic  sandstones  of  the  Atlantic  coast.  Science,  n.  s.,  vol.  1, 
p.  74. 

1895.  W.  O.  Crosby.  Eeport  on  serpentinic  or  verd  antique  marble  in  Westfleld. 
Cited  in  correspondence  of  Springfield  Eepublican,  Feb.  3,  1895. 

1895.  B.  K.  Emerson.  Serpentine  j)seudomorphs  after  olivine,  formerly  called  salt 
pseudomorphs  (from  Middlefleld).    Bull.  Geol.  Soc.  Am.,  vol.  6,  p.  473. 

1895.  B.  K.  Emerson.    Calcite  pseudomorphs  after  salt  in  Triassic  shale.    Ibid.,  p.  473. 

1895.  B.  K.  Emerson.  Puckering  of  corundum  crystals  around  allauite  (from  Pel- 
ham).    Ibid.,  p.  47. 


782  GEOLOGY  OF  OLD  HAMPSHIEE  COUNTY,  MASS. 

1895.  B.  K.  Emersou.    The  geology  of  Old  Hampshire  in  Massachusetts.    Abstract. 

Bull.  Geol.  Soc.  Am.,  vol.  6,  p.  473;  American  Geologist,  vol.  16,  p.  238. 

1896.  B.  K.  Emerson.    The  Archean  and  Cambrian  rocks  of  the  Green  Mountain  range 

in  southern  Massachusetts.  Title,  Proc.  Am.  Assoc.  Adv.  Sci.,  vol.  44,  p. 
149;  abstract,  American  Geologist,  vol.  1(5,  p.  247. 
1895.  Anon.  Another  vein  of  corundum  discovered  by  a  Chester  man.  Announces 
the  discovery  of  corundum  by  Dr.  H.  S.  Lucas  a  mile  east  of  Middlefleld,  and 
repeats  the  history  of  the  original  discovery  at  Chester.  Springfield  Repub- 
lican, December  12,  1895. 

1895.  J.  Volney  Lewis.     Corundum  of  the  Appalachian  crystalline  belt.    Trans.  Am. 

Inst.  Mining  Eug.,  Atlanta  meeting,  October,  1895. 

1896.  E.  H.  Forbes.     On  the  epidote  from  Huntington,  Mass.,  and  the  optical  jiroper- 

ties  of  epidote.    Am.  Jour.  Sci.,  4th  series,  vol.  1,  p.  26. 

1896.  Dwight  Porter.    The  flow  of  the  Connecticut  Eiver.     Science,  u.  s.,  vol.  3,  p.  579. 

1896.  C.  H.  Hitchcock.  The  geology  of  New  Hampshire.  Journal  of  Geology,  vol. 
4,  p.  44.  Review  of  the  report  of  the  Second  Geological  Survey  of  New 
Hampshire,  and  statement  of  the  changes  In  the  classiflcation  of  the  rocks 
there  made,  dependent  on  later  study  of  New  England  geology;  with  refer- 
ence to  the  Bernardstou  sei'iea,  Leyden  argillite,  etc. 

1896.  New  topographical  atlas  of  Hampden  County;  33  maps;  J.  Richards  &  Co., 
Main  street,  Springfield,  Mass. 

1896.  The  building  stones  of  Pennsylvania.     Appendix  Ann.  Rept.  Pennsylvania 

State  College.    Reports  building  stones  of  Massachusetts. 

1897.  B.  K.  Emerson.    Diabase  pitchstone  and  mud  inclosures  of  the  Triassic  trap  of 

New  England.    Bull.  Geol.  Soc.  Am.,  vol.  8,  pp.  59-86,  pis.  3-9. 
1897.  Gilbert  H.  Montague.    Fossil  bird-track  discoveries  in  the  Connecticut  Valley. 

Springfield  Republican,  November  14,  1897. 
1897.  Anon.     Further  finds  of  tracks  at  Mount  Tom.    Ibid.,  November  15,  1897. 
1897.  William  Orr,  jr.     Studies  in  local  geology.     1.  The  trap  ridges   of  Holyoke. 

Ibid.,  November  28,  1897. 
1897.  J.  C.  Rand.    Minerals  of  Massachusetts.    The  Mineral  Collector,  vol.  4,  p.  161  &. 


24 


U.S.  GEOLOGICAL  SURVEY. 


MONOGRAPH  XXIX.  PL.  XXIV. 


MONROE. 


ROWE. 


HEATH. 


ROWE   SCHIST.  SAVC'Y 

AMPHIBOLITE. 


HAWKEY  SCHtST 

OOSHtN  SCHIST. 

AMPHIBOUTE. 


GOSHEN   SCHIST 


SECTIONS    ALONG    LINES    I    TO    IV    ON   GEOLOGIC    MAP. 


25 


U.  S.  GEOLOGICAL  SURVEY. 


MONOGRAPH  XXIX.  PL.  XXV. 


WINDSOR 


ASHFIELD. 


CONWAY  SCHIST. 


Sea  Lgvel 


ROWE  CHESTER 

SCHIST.      AMPHIBOLITE. 


WORTHINGTON. 


CHESTERFIELD. 


VI. 


PEOMATITE. 


ROWE                                     SAVOr 

HAWLEY 

GOSHEN 

^"'9T.      „..^^^^„         SCHIST. 

AMPHrBOLITE. 

CONWAY  SCHrST. 


LIMESTONE. 

AMPHIBOLITE. 


MIDDLEFIELD 


CHESTER. 


CHESTERFIELD. 


WESTHAMPTON. 


VII.     SERPENTINE, 


Sea  Leveli  \  \  \ 

CHESTER 
AMPHIBOLITE, 


LIMESTONE. 


CHESTER. 


HUNTINGTON. 


WESTHAMPTON. 


Sea 

ROWE  CHESTER  SAVOY 

SCHIST.   AMPHIBOLITE.  SCHIST. 


GRANITE.     CONWAY 
SCHIST. 


SECTIONS    ALONG    LINES    V  TO  VIII    ON    GEOLOGIC    MAP. 


26 


U.  S.  GEOLOGICAL  SURVEY. 


BLANDFORD. 


MONTGOMERY. 


MONOGRAPH  XXIX.  PL.  XXVI. 


SOUTHAMPTON. 


Sea  Leval 


MUSCOVITE  GRANITE. 


SUQARLOAF  ARKOSE. 


CHESTER  AMPHiaOLITE. 


BLANDFORD. 


RUSSELL. 


WESTFIELD. 


X. 


iTTVn'^^N:^! 


Sea 


.■By«yil5£§l^^>^;^^iill 


PEGMATITE. 


A\l\\\l; 


BECKET  QNEISS. 


HOOSAC 
SCHIST. 


BECKET        QNEISS. 


HOOSAC  SCHIST. 


.  ;  "Li.".'  ■feJgJJ--.  Atr 


TOLLAND. 


CHESTER  AMPHIBOLITE. 


GRANVILLE. 


SAXONITE    IN  ,.' 

CHESTER  AMPHIBOLITE''. 


CONWAY  SCHIST. 


SOUTHWICK. 


XI.  

'"f "///,'/.'! :::: 
Lever////// //„-  •• ,' :•  ■: 


Sea  Levef. 


rTTrrrr^;,^. 


PEGMATITE. 


BECKET  QNEISS. 

WASHINGTON   QNEISS. 


i:!!;!;'ii\i\\\vvxy^a  \\v; 


HOOSAC  SCHIST.    SAVOY  SCHIST. 
CHESTER  AMPHIBOLITE. 


HOOSAC  SCHIST. 


i  Alill 


HOOSAC  SCHIST. 


PHIBOLITE. 


SAVOY  SCHIST. 


BECKET  QNEISS.       HOOSAC  SCHIST.  SAVOY  SCHIST. 

SAXONITE. 
MUSCOVITE  ORANITE. 


SUQARLOAF  ARKOSE. 


TOLLAND. 


GRANVILLE. 


SOUTHWICK. 


XII. 


till 
til 
Sea  Level, 


^"  'Jill  i.i  XxxMihitinuy. 


WASHINGTON   QNEISS. 


BECKET   QNEtSS. 


HOOSAC  SCHIST.  H005 

CHESTER  AMPHIBOLITE. 


■lOVITE   GRANITE.       BECKET   QNEISS. 


PEGMATITE 
IN  HOOSAC  SCHIST. 


SUQARLOAF   ARKOSE, 


UONGMEADOW 

SANDSTONE. 


SECTIONS    ALONG    LINES    IX  TO  XII    GEOLOGICAL     MAP. 


27 


U.  S.  GEOLOGICAL  SURVEY. 


MONOGRAPH  XXIX.  PL.  XXVII. 


HALIFAX. 


GUILFORD. 


VERNON. 


CONWAY  SCHIST 
WITH  LIMESTONE  BANDG. 


HALIFAX. 


AMPHIBOLITE. 


CONWAY  SCHIST 
WITH  LIMeSTONE  BANDS. 


LEYDEN   ARQILLITE, 


GUILFORD. 


LEYDEN. 


BERNARDSTON. 


VERNON   0NEIS8. 
(  DEVONIAN.) 


GILL, 


CONWAV  SCHIST 
WITH   LIMESTONE   BAND 


AMPHtBOLITE. 


CONWAY  SCHIST,   WITH   LIMESTONE   BANDS. 


LEYDEN    ARQILLITC 


QtJARTZITE.  I  QUAHTZITE.  ;  t  ;         QUART2ITE. 

LIMESTONE.  MICA  SCHIST      ;  j 

AMPHIBOLITE.' 

BERNARDSTON 
(DEVONIAN,) 


MICA  SCHIST  AND 
AMPHIBOLITE. 


SHELBURNE. 


GREENFIELD. 


MONTAGUE. 


.^     .^ 


MON80N     GNEISS. 


HAWLEY 
AMPHIBOLITE. 

CONWAY 


AMPHIBOLITE,  QUARTZITE 

WITH     BANDS     OF     LIMESTONE. 


SUQARLOAF 
ARKOSE. 
SCHIST 


DIABASE. 
LO  NQM  E A  DOW 


^^^^^511 


SANDSTONE. 


BECKET  QNEISS. 


LEYDEN   ARQILLITE 

BERNARDSTON   QUARTZITE, 


CONWAY 


DEERFIELD. 


MONTAGUE. 


CONWAY  SCHIST, 

WITH   LIMESTONE   BANDS. 


AMPHIBOLITE. 


SUQARLOAF  ARKOSE. 


BECKET  QNEISS. 


BERNARDSTON 
QUARTZITE. 


SECTIONS   ALONG    LINES   XIII  TO  XVI   ON    GEOLOGICAL    MAP. 


^ 


28 


U.  S.  GEOLOGICAL  SURVEY. 


MONOGRAPH  XXIX.  PL.  XXVMI. 


DEERFIELD. 


XVII.    r 


SUNDERLAND.   ,  o 

HOLYOKEMT.  >; 

i    DIABASE.  1^^  ^ 

.t    !  MT.  TOBY  CONGLOMERATE. 


LEVERETT. 


CONWAy  SCHIST. 


Sea  Level. 


BHIMFIELD  SCHIST. 


ROWE  BfllMFlELD 

SCHIST.         SCHIST. 

CHESTER  AMPHIBOUTE. 


'H'J' 


HATFIELD. 


AMHERST. 


fJ^^ 


i»->X 


CONWAY  SCHIST.  AMPHIBOLITE. 

LIMESTONE. 


BRIMFIELD   FIBROLlTiC   RUSTY  SCHIST   FULL  OF    PEGMATITE. 


WILLIAMSBURG. 


SOUTH  HADLEY. 


GRANBY. 


BLACK  ROCK 
DIABASE. 


MT.  HOLVOKE     aRKOSE. 
DIABASE. 


LONGMEADOW     SANDSTONE. 


.  ?__ 


SECTIONS    ALONG    LINES    XVII  TO  XIX    ON     GEOLOGICAL     MAP. 


29 


U.  S.  GEOLOGICAL  SURVEY. 


MONOGRAPH  XXIX.  PL.  XXIX. 


SOUTHAMPTON. 


SOUTH  HADLEY. 


GRANBY. 


MT.  TOM.  -^ 


Saa  LeyaLilVjiyli 


WESTFIELD. 


SUQARLOAF  ARKOSE. 


WEST  SPRINGFIELD. 


LONQMEAOOW  SANDSTONE. 


CHICOPEE. 


CRYSTALLINE  SCHISTS. 


XXI. 
Sea  LeveT 


CRYSTALLINE   SCHISTS. 


WESTFIELD 


SUQAHLOAF   ARI?OS£ 


LONQMeADOW   SANDSTONE. 


CRYSTALLINE  SCHISTS. 


WEST  SPRINGFIELD. 


SPRINGFIELD. 


XXII 
Sea  LavefXlI 


^1  -v  /''l^/ 


CRYSTALLINE  SCHISTS. 


SUFFIELD,  CONN. 


BUCK   HILL. 


ENFIELD. 


XXMl; 

Sea  Level' 


i  1 


LONQMEADOW     SANDSTONE. 
1 A 


5  Miles 


SECTIONS    ALONG    LINES    XX  TO  XXIII   ON  GEOLOGIC    MAP. 


30 


U.S.  GEOLOGICAL  SURVEY. 


NORTHFIELD. 


WARWICK. 


RICHMOND.  N. 


LEYOEN   AROILLITE 


BERNARD8TON  MICA  9CHI8T 
WITH  HORNBLENDE  BANDS. 


6EflNAR0ST0N   QUARTZtTE 

CONWAV  SCHIST. 

fiOWE  SiCHIST. 


BECKET    ORANITE. 
QNEtSS, 


ROWE   ;     SAVOY 
SCHIST.i     SCHIST. 
CHESTER  AMPHIBOLITE. 


CONWAY  SCHIST. 


AMPHIBOLITE 


:     BECKET  QNEISS. 
CHESTER;  AMPHIBOLITE, 
SAVOY   SCHIST. 


MONOGRAPH  XXIX.  PL.  XXX. 


XXIV. 


CONWAY 
CHESTER  SCHIST. 

AMPHIBOLITE. 

SAVOY    SCHIST. 


NORTH  FIELD 


ORANGE. 


BERNARD3T0N   MICA  SCHIST 
WITH   HORNBLENDE  BANDS. 


GILL. 


ROWE  S(i"4''' 
CHESTER  AMPHIBpLITE. 
S<ivOY  dcHIST, 
BRUSH   MT.   SCHIST, 


ERVING. 


CHESTER    AMPHIBOLITE.      ;  ^^^^y     SCHIST. 


CONWAY 
SCHIST. 


CHESTER      AMPHIBOLITE. 


ORANGE. 


XXVI 


SAVOY  SCHIST. 


CONWAY  SCHIST. 


MT.  TOBY  CONO. 
BERNARDSTON  SERIES. 


CONWAY  SCJitST.  BECKET  QNEISS.      SJaVOY  SQ'HIST.      CONWAY 

ROWe     SCHIST.     ROWE    SCHIST.  :   .  SCHIST. 

CHESTER  AMI^HieOLITE.  CHESTER  AMPHIBOLITE. 

ROWE  SCHIST. 


BRIMPIELD 

SCHIST 

CHESTER 


A \\  \  I  i  I  «  '  . '  /  M  /  ,  Mi  M  ^  ,  yTTTTT f  n'WUH^B 

i^W.  :  '.    in  .M  'M   ..MM    '«...,>  MMJ^P^WL^^^ 

BECKET  QNEISS.  ROWEScHIST.  ;      ■; 


^XXVI. 


AMPHIBOLITE. 


ROWE  Schist.; 

CHESTER   AMPHlfiOLITE. 

BRIMFIELD  SCHIST   WITH 
AMPHIBOLITE,   RBROLITIC. 


LEVERETT. 


SHUTESBURY. 


NEW  SALEM. 


XXVII. 


.^   N 


^  v\    \  \  TOV\\\?Ss^g<^^^ 


ROWE  SCHIST. 


CONWAY  SCHIST.     SAVOY  BECH 

SAVOY   SCHIST.  SCHIST. 

CHESTER  AMPHOBOLtTE.  CHESTER  AMPHIBOLITE. 


--    t_- 


SERPENTINE. 


SECTIONS    ALONG    LINES    XXIV  TO  XXVII   ON    GEOLOGIC    MAP. 


31 


U.S.  GEOLOGICAL  SURVEY. 


MONOGRAPH  XXIX.    PL.  XXXI. 


LEVERETT. 


SHUTESBURY. 


NEW  SALEM. 


DANA. 


XXVI 


Saa  Level 


SAVOY  SCHIST.        GRANITE, 
CHESTER  AMPHIBOLITE.  CONWAY  SCHIST. 


SAVOY  SCHIST. 


CHESTER 'AMPHIBOLITE. 
SAVOY    sChIST. 


xxvin. 


BECKET  QNEISS. 


AMHERST. 
XXIX. 

AMHERST  SCHIST 


PELHAM 


GREENWICH. 


DANA. 


Sea 


CONWAY     SAVOY 
SCHIST.     SCHIST. 


AMHERST. 


AMHERST  SCHIST 

Sea  Level, 


SAVOY   SCHIST 
PEUHAM   QUARTZITE. 


CHESTER  AMPHIBOLITE. 

CONWAV  SCHIST. 


PELHAM. 


ENFIELD. 


GREENWICH. 


CHESTER  AMPHIBOLITE. 


XXX. 


S^O.A'  W  Vj A\ ,  ,  ■  1 1  ■  »  .  ■  ■  ■  1 »  .  \  \  .  \  ■  ■  <  >  ■  1  .  . .  ■  .  1 


^_ 


CONWAY  SCHIST.     TONALITE.  BECKET  QNEISS. 


PELHAM 
QUARTZITE, 


PELHAM  qUaRTZITE.    schiST. 


CONWAY 
3AV0V        SCHIST. 


SAVOY  ;  SCHIST. 

CHESTER  AMPHIBOLITE. 


BECKET  GNEISS. 


CHESTER    AMPHIBOLITE. 


LUDLOW. 


Sea  LeveU';:;->';;.Vt/aj?.' 


SUQARLOAF  SAVOY 

AHKOSE.  SCHIST. 


T^i— tf^^TT^ii  (,''  ".  I  mm??^, 


BELCHERTOWN. 


BRIMFtELO  SCHIST. 


PALMER. 


XXXI 


BECKET  QNEISS. 
ROWE  SCHIST. 


CHESTER  AMPHIBOLITE. 


SAVOY        BHIMFIELD 
SCHIST.        SCHIST 

FIBROLITIC. 


ROWE  feCHIST.  CONWAY  SCHIST  FIBROLITIC, 


AMHERST 


GRANBY. 


BELCHERTOWN. 


XXXII. 


GRANBY  TUFF 


SUGARLOAF. 


Wmm!mmf^Smm;^rn:tl 


HOLYOKE   DIABASE 


SECTIONS   ALONG    XXVIII  TO  XXXII    ON     GEOLOGICAL    MAP. 


32 


U.  S.  GEOLOGICAL  SURVEY. 


MONOGRAPH  XXIX.  PL.XXXII. 


SUOARLOAF 
AflKOSE. 


CHESTER  AHPHlfiOUTE. 
ROWE  'schist. 


SAVOY  SCHipT. 
AMPHlBQUTEj     QNGI88.  BRIMFIECD  SCHIST.! 

CONWAY  pCHIST.  HARDWICK  GNEISS. 

CHESTER'  AMPHieOUTE. 


SPRINGFIELD. 


WILBRAHAM. 


PALMER. 


XXXIV. 


Sea  Levei;xr-:- '.-"----:: -^-~.--r-r-:'--r-£'-^:->-^'cT^rr^ 


SUOARLOAF  ARK08E. 


MT.   TOBY   CONGLOMERATE. 


CONWAY     Ct^STER   AMPHIBOLITE.  BECKET  GNEISS. 

SCHIST.  { 

SAVOY   SCHIST. 


sikVOY  fee  HIST. 
QXiwUK'i  SCHIST. 


R'OWE  SCHIST. 


CHESTER    AMPHIBOLITE.  GRANITE. 

CONWAY  SCHtST.  BRIMFIELD  SCHIST.  HARDWICK 

GNEISS. 


SPRINGFIELD. 

^     XXXV 


WILBRAHAM. 


MONSON. 


BRIMFIELD. 
XXXV. 


Sea  LevflL  ■ 


LONQMEADOW 
SANDSTONE 


■;uqarlo.:f 


rJGLCiMERATE.      CONWAY     SAVOY   SCHIST. 
SCHIST.  i 

CHESTER  A^S|PHIBOLITE. 


BECKET        GNEISS. 


LONGMEADOW. 

XXXVI. 


HAMPDEN. 


CONWAY      SAVOY 
SCHIST.  I 

CHESTJER   AMPHIBOLITE". 
SAVOY  SCHIST.  ROW^  SCHIST. 


MONSON. 


SCHIST.      DIABASE.       BECKET  GNEISS. 


I      BRIMFIELD  SCHIST    HARDWICK 
CHESTER  GNEISS. 

AMPHIBOLITE. 


BRIMFIELD 


WALES. 


XXXVI 


^^:^^^r^\ 


LONGMEADOW 
SANDSTONE. 


SUQARLOAF 
ARKOSE. 


MT.  TOBY 
CONGLOMERATE. 


CONWAY 

SCHIST. 

SAVOY 

SCHIST. 

CHESTER 
AMPHIBOLITE. 

BECKET  QNEISS. 

CHESTER  AMPHteOlilTE.             \  CHESTER    AMfJHIBOLITE. 
SAVOY  SCHIST.      SAVOY  SCHIST.               ; 

CONWAY'SCHIST.                      ROWE  SCHIST. 

BECKET  GNEISS. 

CHESTER       i                HAHDWICK 
AMPHIBOLITE.;                   QNEISS. 

BRIMFIELD  SCHIST. 

BRIMFIELD 
SCHIST 

SECTIONS    ALONG    LINES    XXIII  TO  XXXVI    ON     GEOLOGICAL     MAP. 


INDEX 


A.  Page. 

Actinolik'-quurtzito.  Pelham  and  Wilbraham 45-47 

Actinolite-tremolite-gneiaa,  occurrence  of 46 

Adams,  C.  B.,  cited  ou  Green  Mountain  gneiea 67 

Albitc,  occurrence  ol" '^^'^ 

Albitic  granite,  occurrence  and  character  of 323-331 

crushing  of  minerals  in 329 

liydrotbenual  cbauges  in  veins  of 32£>-330 

Albitic  mica  schist,  areas  of 66-76 

75 
..  19-30 
754 
133 
6 
133 
221 


liornblendic  bands  in 

Algonkian  rocks,  description  of 

Allauite,  occurrence  of 

Alliu,E.S.,  report  on  Chester  emery 

Ames,  James  T.,  raineralogic  Tvork  of 

report  on  Cheater  emery  by 

Amherst,  analyses  of  hornblende  schist  from  . . . 

Conway  schist  in 222-225 

Amherst  Eidge,  terrace  along 644-649 

Amherst  schist,  correlation  of 224 

minerals  in 224-225 

Ami)hibolites,  occurrence  of 66-177 

descriptions  of 96-97 

Chester  series 147-155 

derivation  from  limestones 153, 154 

analyses  and  sections  of 167, 168, 195-196, 300-306 

Conway  schist 189-196 

"Whately 192-194 

Leverett  and  Amherst 218-220 

Warwick 227-228 

Orange 228 

metamorphism  of 236-237 

pyroxenic 243-246 

Bernardston  series 293-294 

porphy ritic  character  of 304 

Amygdaloid  al  sandstone,  description  of 435-436 

Analyses,  amphibolite 167, 168, 195-196, 303 

andesine 140 

claystones 717 

Coles  Brook  limestone 27 

cortlandite 347 

diorite 345 

emery 125 

gneiss - 62 

granite 37,  316 

Hinadale  limestone 26 

hornblende  schist 221 

indianite 140 

limestones 26,27,189 

Longm  eadow  sandstone 369 

mineral  spring  waters 750-752 

Monson  gneiss 62 

pitchstone 437 

sandstone 369 


Page. 

Analyses,  serpentine 84,88, 116-117 

tonalite , 336 

trap  rock ■>' 464 

waters  of  mineral  springs J 750, 752 

Andesine,  analyses 140 

Ankerite,  occurreuce  of f 754 

Anorthite,  South  Hadley \ 485 

Anthophyllito,  description  of 52 

occurrence  of 754^755 

Anthracite,  occurrence  of 755 

Antigorite-serpentine , 98 

Apatite,  occurrence  of 755 

Aplite,  occurrence  of 331 

Aragonite,  occurrence  of 755 

Argillite,  description  of 201-210 

quartzite  in , 202 

Bernardston  series 261-262 

areas  of 272-273 

pseudo-glacial  strite  on 531-532 

Artesian  wells,  records  of 380-389 

Asbestiform  anthophyllit.e 52 

Asbestos  c[uarry  at  Pelham,  description  of 47-54 

figures  of  walls  of  -  - 48, 49 

Ashfieldlake,  deposits  of 601-602 

Athol,  eastern  synclin  e  in 234-236 

metamorphism  of  amphibolite  at 236-237 

biotite-muscovit'j-sranite  from 316-317 

section  in 572 

Augite,  South  Had4ey 486 

B. 

Barite,  occurrence  of 755 

Bastite,  occurrence  of 755 

Bastite-serpentlne,  occurreuce  of 98 

Batterson's  quarry,  South  Hadley,  dike  at 489 

Bear  Eiver  lake,  deposits  of 600-601 

Becket,  conglomerate-gneiss  at 31-38 

gran itoid.  gneiss  from 36 

crushinjr  tests  of  granite  from 36-38 

Becket  gneiss,  contact  with  "Washington  gneiss 31-32 

Belchertoypn,  contact  zone  in 243-248 

section  of  schists  near 244 

record  of  artesian-well  boring  in 245 

descriptioi.s  of  rocks  from 246-248 

cortilandito  at 346-347 

dit/es  in 481^82 

de,8criptJoji  of  former  lake  in 575-577 

sfe,ction  :a 670 

Belc'hertown  tonaUte,  contact  zone  around 243-248 

Bernardston,  table  showing  succession  of  rocks  near.  258 

/Upper  Devonian  fossils  of 259-260 

I   description  of  range  from  South  Vernon  to 272-282 

HemardsJon  gneiss,  Montague 362-363 

/  783 


784 


INDEX. 


Page. 
Bemardsi  \  ^  series  of  DcTonian  rocks,  discussion  of.  253-300 

descri^\''ioii  of  region  of 260-261 

relation  to  argillite 261-262 

fault  in... 265 

limestone  '.of 265-267 

magnetite  I'ed  iii 267-268 

quartzite  bed  in 268-269 

mica-scliist  and  liovnblendic  beds  in 270-271,  276-282 

feldspathic  quartzite  of 282-283 

beds  of J 285 

original  cbaraclter  and  metamorpbism  of 285-287 

petrograpbical  ^description  of 287-295 

Beryl,  occurrence  oA- 755-756 

Eiotite-gneiss,  descri5)tion  of 44-45,182-183 

Eiotite-granite.Cheste-'field 318-322 

Biotite-muscovite-granite,  occurrence  and  cbaracter 

of 314-318 

Biotite-quartz-scbiat,  Ee\  uardston  series 289-290 

Black  Rock  core,  Mount iHolyoke,  description  of 489-404 

contact  -^vith  diabase  /figured) 490 

Blandford,  Hoosac  acliist  in 73-75 

py  roxenite  in ii 85-90 

Blandford,  serpentines  in.  A 85-90, 102-104, 104-108,  111 

ampbibolites  at .V 96-97 

Savoy  schist  in -V 159 

description  of  biotite-gneW  from 182-183 

dikes  in \ 327 

Blue-qnartz  gneiss -V 28 

Bolton  limestone,  metamorpbisiw  of 155 

Boston  and  Albany  Railroad,  sed^ion  along 71-72 

Bo-\vlders,  description  of \ 559-561 

Bowlder  trains \j 549-550 

Brirafield,  cordierite  granitite  at  -i 321-322 

garnet-biotite-uorite  at \ 345-346 

description  of  former  lake  in. -A 565-566 

Brimfleld  station,  section  at .V 566 

Brown,  M.  A.,  mineralogic  work  of . .  \^ 6 

Brookite,  occurrence  of i 131 

Buckland  lake,  deposits  of 602-603 

C. 

Calcite,  occurrence  of 756 

Calcite  and  dolomite,  pseudomorphs  of 383-391 

Cambrian  (Lower)  gneisses 31-65 

Camp  Meeting  cutting,  sections  at 677-691, 694 

junction  of  clays  and  sands  at 705 

Ceruasite,  occurrence  of 756 

Cbalcopyrite,  occurrence  of , 131 

Chamberlain,  "W.  G.,  report  on  Chester  etaiery  by 133-134 

Cbamplain  clays,  description  of 697-721 

junction  of  sands  with -, 705-706 

structure  of 706-707 

time  occupied  in  deposition  of 707 

action  of  ice  on .\ ---  707-709 

joints  in \. --  709-711 

concretions  in \ --  711-718 

fossils  of 1 -  718-721 

Champlain  period,  phenomena  of .V 562-592 

Chandler,  C.F.,  analyses  by A 369 

Charlemont,  mica-schist  from iV 162 

dikes  in  quartz  veins  in I....  169 

Chemical  analyses,     (^ee  Aualj^ses.)  \  . 

Chester,  amphibolite and  serpentine  in i...     7A-156 

sections  at  emery  mine  in \. .    85,\1-11 

history  and  description  of  emery  bed  in \ .  117-147 

Savoy  schist  in i  159,3^0 


Page. 

Chester,  sericite-scbist  from 162 

dikes  in 327 

Chester  amphibolite  and  serpentine,  occurrence  and 

character  of 78-156 

Chester  amphibolite  series,  description  and  correla- 
tion of 147-155 

sedimentary  origin  of 155 

Chester  emery,  mode  of  formation  of 154-155 

Chester  emery  bed,  history  and  description  of 117-147 

Chester  Emery  Company,  organization  andVork  of.  121 

Chester  emery  mine,  association  and  paragenesis  of 

minerals  at 143-147 

Chester  Granite  Company,  quarry  stones  of. 36 

Chester  series,  extent  and  character  of 149 

Chesterfield,  hiotite  gneiss  from 183 

oopiier  mine  at 504 

Chiastolite-schist... 209-210 

Chicopee  shale,  occurrence  and  character  of. 370 

Chlorite-schist,  dikes  and  quartz  veins  in 169 

Chloritoid,  description  of 129 

Clax>p,  O.  M.,  Ttiineralogic  work  of 7 

Clark,  J.  D.,  mineralogic  work  of 7 

Clark  Hill  quarries,   Middlefield,   granitoid  gneiss 

from 34-36 

Clarke,  John  Mason,  cited  on  character  and  age  of 

fossils  from  Bernardston 259-260 

Clay  and  marl  deijosits,  origin  of 459-460 

Clays  and  till,  contacts  of 701-703 

Claystones,  analj-ses  of 717 

Clinochlor,  occurrence  of 756 

Coles  Brook,  sections  at 22, 23 

Coles  Brook  anticline,  description  of 21-24 

Coles  Brook  limestone,  analysis  of 27 

occurrence  and  character  of 27, 28 

College  Hill,  Amherst,  section  at 557 

Connecticut,  origin  of  name '  2 

Connecticut  River,  old  course  of 513-515,  627 

terraces  of 722-738 

oscillations  of 733 

oxbows  of 734 

deflection  of 734-735 

Connecticut  River  lakes,  description  of 609-696 

Connecticut  River  sandstone,  area  of 351-354 

summary  of  history  of 495-500 

Connecticut  River  tributaries,  deflection  of 735 

terraces  of 736 

repulsion  of 746-747 

Connecticut  River  "Valley,  general  geology  of 13-14 

general  description  of 9-10 

Conglomerate-gneiss,  Becket 31-38 

Conway,  mineral  vein  at 504 

deposits  of  old  lake  in 598-600 

Conway  schists,  occurrence  and  character  of 183-201 

gneiss  beds  in 185 

subordinate  beds  in 185-199 

limestone  beds  in 188, 189 

ampbibolites  in 189-196 

protrusion  through  Leyden  argillite  in  Whately  196-197 

cleavage  in 199-200 

.fossils  of 200-201 

■  age  of 204-205 

Leverett 222 

Amherst 222-225 

Cook,  Helen  P.,  analyses  by 84 

Copper  ores,  Hawley  schist 171 

Cordierite,  figured 208 


INDEX. 


785 


Page. 

CordiorltCKninito,  Brimfiohl 321-322 

Correlation  of  rtu-kti,  hi-rtiou  showing 16-18 

Cortlandito,  Holchurtown :t4fi-347 

iiiiiilyHi'H  of 347 

Coruuiloplitlito,  (loacription  of 130 

t'oruiuhioi,  oi'cnroiu'u  of 128,  750 

Cotiriilo,  fij^uioof  luyer  of 174 

Coys  Ilillporpliyriticgniiiiie 319-320 

Coucretionti,  Cham  plain  rlnya 711-718 

Crosby,  W.  0.,  cited  on  niarhlo  of  Westfield 92-93 

cited  on  niica-j^ranitoa 312,  314 

Crushiugtosta,  granite 36-38 

Cuniiuingtonite  (rhodonite),  occurrence  of  .  -  171, 172, 756,  757 
Cuahmana  Brook,  delta  of 640, 641 

D. 

Dana,  E.  S.,  cited  on  Triaasic  diabases 408-409 

Dana,  J.  D.,  cited  on  origin  of  limestone  fragments  in 

trap 460 

Dana,  J.  D.,  titles  and  abstracts  of  papers  on  TTpper 

Devonian  rooks 253, 254,  256, 257, 259 

Dana,  J.  D.,  titles  of  papers  on  Pleistocene 508 

Datolite,  occurrence  of 757 

Davia,  W.  M.,  cited  on  Cretaceous  degradation 8 

cited  on  trap  rocks 409-410 

Deerfield  bed,  description  of 476 

Deertield  Kiver  and  tributaries,  description  of 597-598 

Deerlield  River,  delta  of 634-635 

Deertield  River  lakes,  deposits  of 595-597 

Deerfield  sheet  of  eruptive  rock,  description  of 418-446 

normal  diabase  of 441-443 

diopside-diabase  of 443-444 

Delaney 's  quarry,  Northampton,  section  at 470 

rocks  at 470-473 

hollow  bomb  from 480 

Deltas  at  high  level,  traces  of 605-606 

Dennis,  L.  M.,  analysis  of  granite  by 36-37 

Devonian  argillites,  pseudo-glacial  striae  on 531,532 

Devonian  rocks,  "Williams  Farm,  map  and  sections.  263-264 

Dewey,  C,  cited  on  mica-granites 312,313 

Diaspore,  nature  of 129 

Diabase,  Deerfield  and  Holyoke 372 

dikes  of 411-418 

alteration  of 419-439 

contact  of  sandstone  with -439,452,455-456 

description  of 441-443, 461-464 

Deerfield  sheet 441-443 

limestone  inclusions  in 452-455 

granitic  inclusions  in 483-488 

Diabase  amygdaloid,  contact  witli  clayey  limestone 

(figured)  208 

Diabase-pitchstone,  description  of 432-433 

Diabase-tuff,  occurrence  and  character  of ,  369 

Dike  rocks,  description  of 324-328 

Dikes,  Charlemont I(i9 

pegmatite 216 

diabase 411-418 

Diller,  J.  S.,  titles  of  papers  on  Pleistocene 508 

quoted  on  geology  of  TTcstfleld  and  vicinity 654^656 

Diorite,  Prescott  (figured) 208 

North  Prescott  and  New  Salem 342-345 

Leverett  Center 34^345 

analyses  of 345 

Diopside-diabase,  Deerfield  sheet 443-444 

Dolomite  changing  to  serpentine,  (figured) 106 

Dolomite  and  calcite,  pseudomorphs  of 389-391 

MON  XXIS 50 


l»age. 

Drift,  upland 535-537 

valley 537-543  . 

Dry  Jirook  Hill,  gorge  terrace  of 601-662 

Druniliiis,  (leseriptioii  of 543-549 

Dunes  and  wind  loess,  occurrence  of 748-749 

Dwigbt,  Timothy,  (luoted 6U9 

Dwight  station,  sections  near 609,671 

E. 

Eakins,  L.  G.,  analyses  by 167, 

168, 196,  221,  303,  316,  336,  345,  347 

Eastern  syncliue,  description  of *.  234-242 

East  Greenwich-Enfield  syucline 251 

Eaton,  Amos,  cited  on  occurrence  of  serpentine  at 

Loudville 190 

cited  on  mica-granites 312 

Eights,  James,  cited  on  plants  of  Champlain  clays . .         718 

Emery,  analyses  of 125 

varieties  of 126-127 

map  of  veins  of 136 

mode  of  formation 154-155 

Emery  bed,  Chester,  description  of 117-147 

section 141 

association  and  paragenesis  of  minerals" at 143-147 

Emmons,  Ebenezer,  early  mineralogic  work 4 

cited  on  mica-granites 312 

Enfield,  rocks  in 232-233 

Enfield- Greenwich  basin .- 9 

Enstatite,  formation  of 148-153 

altered  to  serpentine  (figured) 106 

occurrence  of 757-758 

Enstatite-serpentines,  Granville  and  Russell 90-92 

Russell 111-112 

Enstatite-serpentine  and  limestone  complex  at  "West- 
field  marble  quarry 147-155 

Enstatite-serpentine  pseudomorphs  in  white  marble 

(figured) 152 

Epidote,  description  of 130 

occurrence  of 758 

Epidote-fibrolite,  Northfield 328 

Epidote-gneiss,  Pelham 54 

Erratics,  description  of 559-561 

Eruptive  rocks,  enumeration  of 14 

description  of 307-350, 407-501 

contact  effects  of 349-350 

Eruptions,  epochs  of 410,411 

P. 

Fall  River,  fault  at  mouth  of , 439, 440 

old  course  of 621,  622 

Faults,  descriptions  of 95-96 

Feldspathic  quartzite,  Eernardston  series 282-283 

Fibrolite,  occurrence  of 229-758 

Fibrolite-schist,  Belchertown 246-248 

Field,  Roswell,  early  geologic  work 6 

Fishes,  Triassic 398-400 

Fitts,  F.  H.,  analyses  by 26,336 

Florence,  analyses  of  granite  from 316 

Flynt's  quarry,  Monson,  gneiss  at 59-65 

Foot  tracks  and  trap  sheets,  possible  connection 

between 379 

Fort  River,  old  oxbow  of 737-738 

Pleistocene  beetles  of 740-746 

Fossils  of  the  Terrace  period 738-740 

Fox  Brook,  Triassic  sandstone  outcrop  along 271 


786 


INDEX. 


Page. 

Franklin  County,  Eowe  schist  in 76 

K-owe  serpentine  in 79-80 

G. 

Gadrite,  occurrence  of 758 

Galena,  occurrence  of 758 

Garnet,  Northfield 106,328 

Garnet-biotitc-norite,  Brirufield 345-346 

Garnetiferous  quartzite,  figure  of 174 

Glacial  action  in  Triassic  time 363-364 

Glacial  grooves  and  strise 522-531 

Glacial  notclies 529-531 

Glacial  period,  erosion  during 515-517 

topography  during 518-521 

Glacial  and  Triassic  periods,  interval  between 508-517 

Glass  in  trap,  origin  of 437-439 

Glass-breccia,  description  of 433-435 

Gneiss,  Monson 15,  41-45,  56-65 

Hinsdale 20,24^25 

Lee 20,29-30 

Washington 20 

blue-quartz 28 

Lower  Cambrian 31-65 

Middlefield 34-36 

Becket 36 

Shelburne 38^1 

Pelham 43-44 

Orange 56-65 

Goessmann,  C.  A.,  analysis  by ^.  750 

Goshen,  limestone  at 191 

dikes  in 326-327 

galena  at 504 

Goshen  anticline 175-176 

Goshen  schists 177-183 

Granby,  cores  and  dikes  in 482-483 

Granhy  Plain,  moraine  across 664 

Granby  Eoad  Lake,  description  of  deposits  of 587 

Granby  tuff,  occurrence  and  character  of 369 

Granby  tuff  bed,  description  of 476-479 

source  of  material  of 480 

Granite,  Becket,  crushing  tests  of 36-38 

analysis  of 37,  316 

Hardwick 317-318 

Huntington,  crush  ing  of  minerals  in 329 

age  of 348 

genetic  relations  of 348-349 

included  in  diabase 483-488 

Granitite,  occurrence  of 317-322 

Granitoid  gneiss,  Middlefield 34-36 

Becket - 36 

Pelham 43-44 

Granville,  Hoosac  schist  in 73-75 

enstatite-serpentines  in 90-92 

serpentines  at 108-111 

deposits  of  former  lake  in 593 

Graphitic  mica-schist  series 177-210 

Greenfield,  altered  diabase  in 419-439 

exposures  in  quarry  at 424-431 

details  of  trap  ridge  east  of 426 

thin  sections  from  ' '  ash  bed  "  at 430 

mineral  vein  at 505 

terrace  In 632-634 

Greenwich -Enfield  basin 9 

Green  River  glacier,  deposits  of 630-631 

Gulf  road,  sections  on 213-215 


H.  Page. 

Hadley  Lake,  deposits  of 629-657, 673-677 

drainage  of 584-586 

sections  of  beds  of 646, 647 

clays  in 698-701 

Hadley  Lake  basin,  terraces  in 726-729 

Hampden  Emery  Company,  organization  and  work 

of 121 

Hampden  County ,  am pliibolite  and  serpentine  in 85 

Rowc  schist  in 76-78 

Hampshire  County,  Kowe  schist  in 76-77 

former  area  of 1 

serpentine  in 81-85 

Hardwick  gneiss 239-241 

Hardwick  gneissoid  granite  and  grauitite 317-318 

Hassam  Brothers,  report  on  Chester  emery 1 33 

Hatfield,  mineral  vein  at 505-506 

section  of  clays  in 691-692 

Hausmann,  early  description  of  kieselspath  (albite) 

by 5 

Hawes,  G.  "W".,  cited  on  Triassic  diabases 408-409 

analyses  by 463-464 

Hawley ,  great  fault  in 172 

Hawley  schist,  occurrence  and  character  of 163-171 

possible  igneous  origin  of 169 

mineral  deposits  in 170-171 

copper  ores  in 171 

Hayes,  S.  D.,  analysis  by 750 

Heath,  pyroxene-schist  from 163 

ampbiboli  te  from 168 

Hematite,  South  Hadley 486,487 

Hillebrand,  W.  F.,  analyses  by 88 

Hinsdale,  rocks  in 19-24 

Hinsdale  gneiss,  occurrence  and  character  of 20,  24-25 

Hinsdale  limestone,  occurrence  and  character  of. . .  20, 25-27 

analysis  of 26 

Hitchcock,  C.  H.,  titles  and  abstracts  of  papers  on 

Upper  Devonian  rocks,  by 253,254,  255-257 

cited  on  relation  of  limestone  to  quartzite  in  Ber- 

nardston  series 286 

cited  on  recent  progress  in  ichuology 400-404 

Hitchcock,  Edward,  early  geological  work  of 3-6 

cited  on  metamorphism  of  mica-schist 67-68 

analyses  by 188-189,463,464 

titles  and  abstracts  of  papers  on  Upper  Devonian 

rocks  by 253-255 

cited  on  mica-granites 312-313 

cited  on  occurrence  of  syenite 331-334 

cited  on  Triassic  fossils 394-398 

cited  on  trap  rocks 407-408 

titles  of  papers  on  Pleistocene 508 

cited  on  topography  of  Connecticut  Valley 510-511 

cited  on  glacial  notches 530 

cited  on  notable  bowlders 559-560 

cited  on  muck  sand  of  Sunderland 728 

Holyoke,  record  of  artesian  well  at 383-385 

high  terrace  near 662-663 

Holyoke  dam.  crushed  baud  at 370-372 

section  of 371 

Holyoke  Eange,  description  of 10-11 

trap  rocks  in 365-367 

Holyoke  trap  sheet 446-460 

diabase  of 461^64 

fissured  quartz  deposit  in 752-753 

Hoosac  fault,  notes  on 95-96 

Hoosac  schist,  occurrence  and  character  of 66-76 


INDEX. 


787 


llooeac  ai'liist,  hcirnlili'nilic  banila  in 75 

Huiisai'  Tnmicl,  I'luill  iit  c-nst  i«ivM  lit 80-81 

lIcMiililimlo  sihi.st,  uiiiilj  80S 221 

l!()nililiinlio  Imiuls  in  llooano  Bi^lii.it 75 

lliinililoiulii'  liwln.  licrnarilstou  series 270-282 

IIiisriMil,  l!.,inim'ni1o;;ii'  worlc  of 5 

Uul.liara,  A.o.,  cilrd ^ 

lluilson  iiml  Chi'sUTGraiiito  Conirany,  lieokot,  tests 

of  t;raiiite  of 36-38 

Hunt,  David,  early  niincralogic  wiirk  of 4 

Uiintingtim,  mineral  vi'in  at 51'7 

IIyilr(nnica-8c:lii8t 7G-78 

I. 

Ice,  Triasslc   363-364 

Ice  barriers,  positions  of 565 

Ii-lmoli.gy,  Triassio  rocks 400^04 

Inilianite,  description  of 130 

analyses  of l*" 

Insects,  Triassic 398 

Intrusive  rocks  in  Savoy  schist 163 

Irving  station,  section  near 217 

J. 

Jackson,  C.  T.,  cited  on  Chester  emery  bed 119-120 

cited  on  character  of  emery  at  Iforth  Mountain.         138 
cited  on  occurrence  of  emery  at  South  Moun- 
tain    138-139 

cited  on  occurrence  of  andesine  at  South  Moun- 
tain   , 140 

analyses  by 140 

cited  on  width  of  emery  bed  at  South  Mountain .         141 

Julien,  A.  A.,  cited  on  mica-granites 312,314 

cited  on  tourmaline-spodumene  dikes 324,325,326 

cited  on  meteoric  alteration  of  rocks 330 

K. 

Kemp,  J.F.,  cited  on  Becket  granite 36-38 

Kettle-holes,  occurrence  of 664-672 

Kibbe  quarry.  East  LongmeadOTi',  analyses  of  rock  of         369 
King,  "W.,  cited  on  joints  in  clays 710 

L. 

Labradorite,  South  Hadley 485 

Laidley,  T.T.S..  report  on  Chester  emery 134 

Lake  bottoms  and  terraces,   descriptions  and  sec- 
tions of 672-096 

Lazulite,  occurrence  of 758 

Lee  gneiss,  occurrence  and  character  of 20,  29-30 

Leverett,  Conway  schist  in 222 

mineral  vein  at 506 

description  of  former  lake  in 584-586 

Leverett  Center,  amphibolite  and  mica-schist  series 

in 220 

diorite 344-845 

Leverett- Amherst  area,  description  of 218-225 

Leyden  argillite,  protrusion  of  limestone  of  Conway 

schist  through 196-197 

description  of 201-210 

stratigraphy  of 203 

boundary  on  Conway  schists 203-204 

age  of 204-205 

contact  metamorphism  of 205-210 

change  tochiaatolite-achist 208 

Lily  Pond,  GUI,  terrace  at 724-725 


Paga 

Limestone,  Ilinsdah' 20,25-27 

aniilyses  ol 26,27,188 

Cidos  Brook 27-28 

jiyroxi-nit^ 1G3 

Conway  schists 188-180 

Wliateiy 191 

mclaniorphosed  by  granitito 197-199 

fossiliferous,  description , 362-271 

Hernardston  series 265-267,289-200 

I'MU-nurdston 294-295 

included  in  diabase 452-455 

included  in  trap 456-459 

Lithophysfl3,  occurrence  of 436 

Little  Mountain,  Northampton,  trap  sheet  at 466 

Locks  Pond  Lake,  description  of 556 

Loess,  occurrence  of 748-749 

Longmeadow  sandstone,  occurrence  and  character  of  364-369 

analyses 369 

Loudville,  mineral  vein  at 502-504 

Lower  Cambrian  gneisses 31-65 

Lower  Silurian  sericite  schists  and  amphibolites, 

discussion  of 66-177 

Lucas,  H.  S.,mineralogic  work  of 6 

cited  on  Chester  emery  bed 118, 1 20-121 

Lyman,  Benjamin  Smith,  cited  on  New  Eed  horizons .         446 

M. 

Magnet  (The),  a  notable  bowlder,  description 559  560 

Magnetite,  occurrence  of 127-128 

deposits  of 172-174,175 

Bernardston  series 267-268 

South  Hadley 487 

Magnetite-emery  bed,  Chester 117-147 

ICarble,  Westfleld 92-95 

stellate  (dgnred) 152 

Margarite,  description  of - 129 

Marl  and  clay  deposits,  origin  of 459-460 

Masonite,  description  of 129 

Maynard  quarry,  analyses  of  rock  from 369 

Mayr,  Charles,  analysis  by 752 

Meade,  William,  early  mineralogio  paper  by 3 

Meriden,  thin  sections  of  * '  ash  bed  "at 430 

analysis  of  pitchstone  from 437 

Merrill,  G-eorge  P.,  cited  on  cost  and  strength  of  Tri- 
assic sandstone 394 

Mesozoic  time,  erosion  in 515-517 

Metamorphism,  Bernardston  series 285-287 

Meteoric  alteration  of  rocks 330 

Mica  and  amphibolite,  Bernardston  series 291-293 

Micaceous  quartzite,  description  of 46 

Mica-granites,  historical  notes  on 312-314 

Mica-schist,  relation  of  Becket  gneiss  to 72-73 

description  of 162 

South  Orange  and  New  Salem 231-232 

Ware 238-239 

Bernardston  series 270-271 ,  276-282,  291-293 

Northfleld 285 

Mica-schist  series,  description  of 177-210, 218-220 

Hiddlefield,Ho03ao  schist  in 70-73 

serpentine  in 81-85 

porpbyritic  grauitite  in 318-319 

Mill  Ei ver,  Northampton,  section  of  drift  at 540 

delta  of 637-639 

Millers  Falls,  dikes  near 412,413 

Millers  Falls  station,  section  near 666-668 

Millers  Eiver,  rocks  at  mouth  of ^95-299 


788 


IKDBX. 


Page. 

Millers  Kiver  delta,  description  - 625-629 

Mineral  deposits,  Hawloy  schist 170, 171 

Mineral  lexicon  of  Franklin,  Hampsliire,  and  Hamp- 
den counties,  aiipplement  to 754-761 

Mineral  springs,  locations  of 749-752 

analyses  of  waters  of 750-752 

Mineral  veins,  description  of 502-507 

Monroe,  Hoosac  schist  in r 67-70 

Monson,  gneiss  in 15, 41-45, 56-65 

granite  quarries  at 60-65 

rocks  in 241-242 

analyses  of  gneiss  from 316 

dikes  in 414-415 

glass-hearing  dikes  in 616-418 

description  of  esker  in 566-567 

lake  deposits  in 567-569 

Monson  gneiss,  description  of 15,41-45 

analyses  of.. 62 

strengt h  of 63 

expansion  in  quarrying 63-65 

conglomerate  structure  in 63-65 

mineral  vein  in 65 

Monson  syncline 249-250 

Montague,  Bernardston  gneiss  at 362-363 

lake  deposits  in 615-629 

clays  in 697-698 

terraces  in 725-726 

Moore's  quarry,  Florence,  analj'ses  of  rock  from 316 

Moraines  and  bowlder  trains 549, 550 

Mount  Holyoke,  analyses  of  trajj  from 464 

lakehonchon 649-650 

Mount  Toby  conglomerate,  occurrence  and  character 

of 358-363 

Mount  Tom,  faults  at 449-451 

lake  bench  on 640-650 

Mount  "Warner,  bench  around 648-649 

Muscovite-granite,  occurrence  and  character  of 322-323 

Muscovite-schist,  description  of 181-182 

Nash,  A.,  mineralogic  work  of 4-5 

cited  on  mica-granites 312,313 

Kewberry,  J.  S.,  cited  on  Triassic  fishes 398-399 

Newell,  "William,  mineralogic  work  of 5 

New  Salem,  serpentine  in 55,56 

great  central  syncline  in 230 

diorite 342-345 

Niles,  "W.  H.,  cited  on  expansion  of  Monson  gneiss..      64-65 

North  Amherst,  granite  at 323 

breccia  at 363 

Northampton,  record  of  artesian  well  at 385-388 

trap  sheet  in 466 

dikes  in 494-495 

mineral  vein  at 506-507 

section  of  diift  at 540 

Northfield,  description  of  semi-syncline  in 212-216 

quart'zite  in 284 

mica-schist  in 285 

North.  Granville  lake,  deposits  of 593-594 

North  Leverett,  rocks  in 219-220 

North  Prescott,  diorite 342-345 

Northerner  {a  notable  bowlder),  description  of 559 

O. 

Olivine,  occurrence  of 758 

Olivine-enstatite  rock 52 


Page. 

Orange,  gneiss  in 56-65 

great  central  syncline  in 227-230 

eastern  syncline  in 234-236 

Ordway,  John  M.,  letter  on  Monson  granite 62-63 

Orr,  William,  jr.,  analyses  by 336 

Osborn  soapstone  quarry,  Blandford,  section  at 87 

analysis  of  serpentine  from 88 

rocks  at 102-104 

Ottrelite,  description  of 129 

Owen,  Richard,  cited  on  Triassic  reptiles 405 

P. 

Paleontology,  Triassic  rocks 394^406 

Palmer,  rocks  in 241 

former  lake  in...' 569 

Paragenesis,  secondary  minerals,  Deerfield  sheet 444  445 

Peaked  Mountain,  section  near 249-25U 

Pegmatite,  occurrence  and  character  of. 322-323, 328 

Pegmatite  dikes  and  minerals 216,  323-331 

Pelham,  gneiss  in 42-45 

asbestos  quarry  at 47-54 

figures  of  walls  of  asbestos  quarry  at 48, 49 

serpentine  from 55 

diabase  in 413 

microscopic  diabase  dike  from 416-417 

section  in 578 

Pelham  and  Wilbrahani,  actinolite-quartzite  of 45-47 

Pelham  lake  and  esker,  description  of 578-584 

Pelham-Shutesbury  syncline,  description  of 225-227 

Peru,  blue  quartz  of 28 

Pitchstone,  analysis  of 437 

Pitchstone  breccia,  alteration  of  diabase  to 419-439 

Plagioclase-feldspars -  52-54 

Plainfield,  limestone  at 192 

Plant  remains,  Champlain  clays 718-720 

Plants,  Triassic 394-398 

Pleistocene  period,  phenomena  of 508-517 

Pleistocene  heetles  of  Fort  Eiver,  description  of 740-746 

Porphyritic  granite,  occurrence  of 319-320 

Porphyritic  grauitite,  occurrence  of 318-319 

Posterior  trap  sheet,  description  of 464-476 

Pot-holes,  occurrence  of 532-533 

Prescolt,  rocks  in 232-233 

Prochlorite,  occurrence  of 759 

Publications  on  geology  and  mineralogy  of  Franklin, 

Hampshire,  and  Hampden  counties,  list  of  . .  762-782 

Pyrite,  occurrence  of 170-171, 759 

Pyrolusite,  occurrence  of 759 

Pyroxene,  occurrence  of 759 

Pyroxene- schist,  description  of 163 

Pyroxene-serpentine,  Blandford 104-108 

Pyroxenic  limestone,  description  of 163 

Pyroxenic  amphibolites 243-245 

Pyroxenite,  Blandford 85-90 

Q- 

Quartz,  occnrrence  of 169, 752-753, 759 

Quartz-diorite,  occurrence  and  character  of 331-342 

Quartz-gab bro,  occurrence  of 331-342 

Quartz-garnet  rock,  figure  of 174 

Quartz  veins,  Charlemont 169 

Quartzite,  Shutesbury 46 

"Warwick 227-228 

Orange 228 

Bernardston  series 268-269,287-290 

areasof 273-276 

Northfield 284 


INDEX. 


789 


Page. 

405-400 

7-10-747 

-172,  759 

500-501 

473-474 

559 

559 

560 

98-101 

76-78 

77 

158 

79-80 

364 

90-92 

111-113 

163 

507 


E. 

Ecptiloa,  Trinsaio 

Jtcpulaion  uf  trilpiitiii-ioa,  illustnit  iini.s  of 

inicMloiiiti-  (ciiiimiinstouiti'),  iiciuricncu  of 171- 

Eoiul  iiiiitorlal,  use  of  triip  aa 

]!o:i rill;;  lirook,  fiiult  :lt 

l;ork  Elnni  (n  notiililo  bci-wlilor),  (Icsci'ilitioii  of 

Km^U  Ori'li,  iloscription  of 

ItiK-Uin;;  Stoiio  (The),  doscviption  of 

liowi'.  aerpoiitinoa  at 

Howo  schist,  occurreuce  and  cliaraitoi-  of 

section •_ - 

compared  with  Savoy  soliiat 

Rowo  serpcDtine,  section  of 

Eusaoll.  I.  C,  cited  on  action  of  iie  in  Triassic  time. 
Eusaell,  enBtatitc-aerpentiiica  in 

sorpentinea  iu 

pyroxenic  limestone  in 

mineral  vein  at 

S. 

Salilite  clianging  to  ti-emolite,  figured 106 

Salt,  occurrence  of '"" 

Sands,  interglacial 550-558 

Sandstone,  Connecticut  Eiver 351-354 

amygdaloidal 435-436 

contact  of  diabase  w  ith 439, 452, 455-456 

sills  intruded  in - 469-470 

Savoy  scliist,  occurrence  and  cliaracter  of  . .  156-163, 220-221 

intrusive  rocks  in 163 

Saxonite,  Monson  gneiss 47-56 

Schists,  enumeration  of 15,16 

Silurian 211-252 

Schlierengiinge,  E.  Hitchcock's  suggestion  of  the- 
ory of 334 

Scudder,  S.  H.,  description  of  Pleistocene  beetles  liy.  740-746 
Sentinel  (The)  (a  notable  ho-wlder),  description  of..         500 

Sericite-gneiss,  Whately 206-209 

Sericite-schists  and  amphibolites,  description  of 66-177 

Sericite-schist,  description  of 162 

Serpentine,  Monson  gneiss 47-56 

Pelham 54,55 

ohutesbury 55 

Middlefleld 81-85 

analysis 34,88,116-117 

Chester ' 85 

Blandford 85-90 

petrographic  descriptions  of 97-117 

Westfteld 92-95,113-114 

derivation  of 115 

occurrence  of...: 760 

Serpentinization,  exauiples  of 95-96, 147-148 

Shearing,  Weatfield  marble  quarry 148 

Shepard,  C.  U.,  mineralogic  work  of ■ 5,7 

cited  on  Chester  emery  mine 122-135 

cited  on  occurrence  of  indianiteat  Soutli  Moun- 
tain           140 

Shellmrne,  gneiss  at 38-41 

rocks  of  anticline  in 162 

mineral  vein  at 505 

Shelburne  Falls  anticline,  rocks  of 75 

Shutesbury,  serpentine  from 55 

section  in 230 

Siderite,  occurrence  of 760 

Silliman,  Benjamin,  report  by,  on  Southampton  lead 

mine * 3 


Silliman's  .Journal,  cited  on  lead  mines  and  veins 

Silla  intruded  in  sandstone 

Silurian  (Lower)  sericite  scliists  and  amphibolites.. 

Silurian  schists,  east  aide  of  valley 

Smith,  J.  Lawrence,  cited  on  minerals  accouipanying 

emery 

Smitlis  Ferry,  dike  at 

Sodom  Mountain,  serpentine  from 

Savoy  scliist  at 

pyroxenic  limestone  from •  • 

South  Hadlcy,  record  of  artesian  well  at 

dike  rocks  in 

South  Orange,  great  central  ayncline  in 

South  Vernon,  description  of  range  from  Bernards- 
ton  to '. 

Spodumene,  occurrence  of 

Springs  (mineral) ,  occurrence  of 

analyses — 

Springfield  basin,  terraces  in 

Springfield  lake,  deposits  of 

Springfield  lake  bottom,  description  of 

clays  in 

Springfield  Republican,  cited   on   Monson   granite 

quarry 

cited  on  Cheater  emery  bed 

quoted  on  use  of  Triaaaic  sandstone  for  building 

purposes 

State  Line  fault,  Holyoke  dam 

Steatization,  "Weatfield  marble  quarry 

Stellate  marble,  figure  of 

Stokes,  H.  N.,  analysis  by 

Stria;,  glacial 

Sneas,  E.,  cited 

Sngarloaf  arkoae,  occurrence  and  character  of 

Sunny  Valley  lake,  deacription  of 

Swift  Eiver  lake,  description  of 


Pago. 
i 
409-470 

66-177 
211-252 

131 

495 
114 

159 
163 

381-382 
483-494 
230-232 

272-282 
760 
749-752 
750-752 
720-731 
657-665 
077 
.       701 


60-62 
120 

391-394 

370-372 
147 
152 
437 

522-531 
13 

354-358 
592 

569-575 


Talc,  occurrence  of 760 

Taft,  John  B.,  reports  on  Chester  emery  made  to 133-134 

Terraces,  Connecticut  Eiver 722-738 

Terraces  and  lake  bottoms,  detailed  sections  of 677-696 

Terrace  period,  Connecticut  Eiver,  fossila  of 738-740 

"The  Crater,"  North  Blanford,  rocks  at 86,  101-102 

Thomas,  Judson,  acknowledgments  to , 141 

Till,  description  of 533-543 

contacts  of  clays  and 701-703 

Titanite,  occurrence  of 761 

Tolland,  rocks  in 24,73-75 

Tonalite,  occurrence  and  character  of 331-342 

analyses  of 336 

crushing  and  alteration  of 339-342 

Topograijhy  of  the  region -.        8-11 

Tourmaline,  description  of 130 

occurrence  of 761 

Tourmaline  dendrite,  Leeds 316 

Tourmaline-spodumene  dikes,  Cheaterfield 324-326 

Trap,  limestone  fragments  iu 456-459 

underrolling  of 460-461 

Trap  rocka,  Holyoke  range 365-367 

origin  of  glass  in 437-439 

analyses  of 464 

road-making  use  of 500-501 

Trap  sheets  and  foot  track,  possible  connection  be- 
tween    379 

Tremolito  changing  to  serpentine,  figured 106 


790 


INDEX. 


Tremolite  rock,  occurrence  of 108-110 

Treniolltization,  Westfieltl  marTjle  qiiJirry 148 

Triassic  basin,  mode  of  formation  of 373-379 

Triassic  beds,  summary  of  history  of 495-500 

Triassic  eruptions,  three  epochs  of 410-411 

Triassic  eruptives,  occurrence  and  character  of 407-501 

Ti  iassic  glaciers 363-364 

Triassic  fossils 394-406 

Triassic  incks.  description  of 351-406 

general  section  of 354 

sumniary  of  history  of 495-500 

Triassic  sandstones,  thicknesses  of 375 

architectural  use  of 391-394 

Triassic  and  Glacial  periods,  interval  between 508-517 

Tuir,  occurrence  of 47G-481 

Tutfaceous  agglomerate,  occurrence  of 476-481 

Turners  Falls,  record,  of  artesian  well  at 380-381 

mineral  vein  at 505 

y. 

Vernon  limestone,  areas  of 276 

Villarsite,  occurrence  of 758 

Wapping,  section  at  railroad  cutting  in 694-696 

Ware,  rocks  in 237-239 

diabase  dikes  in 414 

Ware  River  Lake,  description  of 569-573 

Warwick,  great  central  aynclinein 227-230 

Warwick  road,  sections  near 215-216 

Washington  gneiss,  occurrence  and  character  of 20 

Washington  gneiss,  contact  with  Becket  gneiss 31-32 

AVashingtonite,  occurrence  of 131 

Wells,  artesian,  records  of 380-389 

Wendell  Branch  syncline 217-218 

West  Brook,  delta  of 635-637 

Westfield-Holyoke  Railroad,  trap  filled  with  lime- 
stone fragments  along 456-459 


Page. 

Westfield,  serpentine  and  marble  in 92-95, 1 13-114 

WestBeld,  sections  in 92-94  ^ 

Westfield  Little  River,  artesian  well  on 389 

Westfield  plain,  deposits  of 650-657 

Westfield  Paver,  deposits  of 607-608 

Westfield  marble  quarry,  eustatite-serpentino  and 

limestone  complex  at 147-155 

Westfield  marble  quarry,  alteration  of  rocks  at 147-155 

Westhampton,  mineral  veins  at 502-504 

lead  mine  at 503-504 

deposits  of  former  lake  in 594-595 

West  Hawley,  section  in 173 

Whately,  ampliibolite  bed  at 190, 192-194 

carbonaceous  limestone  at 191 

protrusion  of  Conway  schist  through   Leyden 

argillitoat 196-197 

mineral  veins  at 504 

Whetstone  schist,  occurrence  and  cliaracter  of 186-187, 

220-221 
Whitfield,  E.  P.,  titles  and  abstracts  of  paper   on 

metamorphic  rocks 254,  256 

Whitmores  Ferry,  Sunderland,  amphibolite  at 1£10  -191, 

104-195 

hornblende-schists  at 361-362 

Wilbrabam,  gneiss  in 42-45 

Wilbraham  syucliue,  description  of 248-249 

Wilbrabam  and  Pelham,  actinoliie-quartzite  of 45-47 

Williamsburg,  mineral  veins  at 505 

deposits  of  glacial  lake  in 595 

Williams  farm,  map  and  sections  of  rocks  at 263,  264.  266 

Williams  farm  section,  description  of 262-271 

Wortliington,  amphibolite  from 167 

Worcester,  analyses  of  rock  from 369 

Z. 
Zoisite,  occurrence  of ■     761 

Zoisite-hematite,  Northfield 328 


[Monograiih  XXIX.] 


The  statute  approved  March  3,  1879,  establishing  the  United  States  Geological  Survey,  contains 
the  following  provisions: 

"The  publications  of  the  Geological  Survey  shall  consist  of  the  annual  report  of  operations,  geo- 
locieal  and  economic  maps  illustrating  the  resources  and  classification  of  the  lands,  and  reports  upon 
general' and  economic  geology  and  paleontology.  The  annual  report  of  operations  of  the  Geological 
Survey  shall  accompany  the  annual  report  of  the  Secretary  of  the  Interior.  All  special  memoirs  and 
reports  of  said  Survey  shall  be  issued  in  uniform  quarto  series  if  deemed  necessary  by  the  Director,  but 
otherwise  in  ordinary  octavos.  Three  thousand  copies  of  each  shall  be  published  for  scientific  exchanges 
and  for  sale  at  the  price  of  publication ;  and  all  literary  and  cartographic  materials  received  in  exchange 
shall  be  the  property  of  the  United  States  and  form  a  part  of  the  library  of  the  organization :  And  the 
money  resulting  froin  the  sale  of  such  x)ublicatious  shall  be  covered  into  the  Treasury  of  the  United 

States."  "  .,.,  .  ^        ^  ■  z  ■  ^.u      z 

Except  in  those  cases  in  which  an  extra  number  of  any  special  memoir  or  report  has  been  sup- 
plied to  the  Survey  by  special  resolution  of  Congress  or  has  been  ordered  by  the  Secretary  of  the 
Interior,  this  office  has  no  copies  for  gratuitous  distribution. 

ANNUAL  REPORTS. 

I.  First  Annual  Report  of  the  United  States  Geological  Survey,  by  Clarence  King.  1880.  8°.  79 
pp     1  map. — A  preliminary  report  describing  plan  of  organization  and  publications. 

II.  Second  Annual  Report  of  the  United  States  Geological  Survey,  1880-81,  by  J.  W.  Powell. 

1882.  8°.     Iv,  588  pp.     62  pi.     1  map. 

III.  Third  Annual  Report  of  the  United  States  Geological  Survey,  1881-'82,  by  J.  W.  Powell. 

1883.  8°.    xviii,  564  pp.    67  pi.  and  maps. 

IV.  Fourth  Annual  Report  of  the  United  States  Geological  Survey,  1882-'83,  by  J.  W.  Powell. 

1884.  8°.     xxxii,  473  pp.     85  pi.  and  maps. 

V.  Fifth  Annual  Report  of  the  United  States   Geological  Survey,  1883-'84,  by  J.  W.  Powell. 

1885.  8°.     xxxvi,  469  pp.     58  pi.  and  maps. 

VI.  Sixth  Annual  Report  of  the  United  States  Geological  Survey,  1884-'85,  by  J.  "W.  Powell. 
1885.     8°.    xxix,  570  pp.     65  pi.  and  maps. 

VII.  Seventh  Annual  Report  of  the  United  States  Geological  Survey,  1885-'86,  by  J.  W.  Powell. 

1888.  ,8°.     XX,  656  pp.     71  pi.  and  maps. 

VIII.  Eighth  Annual  Report  of  the  United  States  Geological  Survey,  1886-'87,  by  J.  W.  Powell. 

1889.  8°.     2pt.     xix,  474,  xii  pp.,  53  pi.  and  maps;  1  p.  1.,  47.5-1063  pp.,  54-76  pi.  .and  maps. 

IX.  Ninth  Annual  Report  of  the  United  States  Geological  Survey,  1887-'88,  by  J.  W.  Powell. 

1889.  8°.     xiii,  717  pp.     88  pi.  and  maps. 

X.  Tenth  Annual  Report  of  the  United  States  Geological   Survey,  1888-89,  by  J.  W.  Powell. 

1890.  8°.    2pt.     XV,  774pp.,98pl.  andm.aps;  viii,  123  pp. 

XI.  Eleventh  Annual  Report  of  the  United  States  Geological  Survey,  1889-90,  by  J.  W.  Powell. 

1891.  8"^.     2  pt.     XV,  757  pp.,  66  pi.  and  maps;  ix,  351  pp.,  30  pi.  and  maps. 

XII.  Twelfth  Annual  Report  of  the  United  States  Geological  Survey,  1890-'91,  by  J.  W.  Powell. 
1891.     8*^.    2  pt.,  xiii,  675  pp.,  53  pi.  and  maps ;  xviii,  576  pp.,  146  pi.  and  maps. 

XIII.  Thirteenth  Annual  Report  of  the  United  States  Geological  Survey,  1891-'92,  by  J.  W. 
Powell.  1893.  8°.  3  pt.  vii,  240  pp.,  2  maps;  x,  372  pp.,  105  pi.  and  maps;  xi,  486  pp.,  77  pi.  and 
maps. 

XIV.  Fourteenth  Annual  Report  of  the  United  States  Geological  Survey,  1892-'93,  by  J.  W. 
Powell.    1893.     8°.     2  pt.     vi,  321  pp.,  1  pi. ;  xs,  597  pp.,  74  pi.  and  maps. 

XV.  Fifteenth  Annual  Report  of  the  United  States  Geological  Survey,  1893-'94,  by  J.  W.  Powell. 
1895.     8°.     xiv,  755  pp.,  48  pi.  and  maps. 

XVI.  Sixteenth  Annual  Report  of  the  United  States  Geologicnl  Survey,  1894-'95,  Charles  D. 
Walcott,  Director.  1895.  (Part  I,  1896.)  8°.  4  pt.  xxii,  910  pp.,  117  pi.  and  maps;  xix,  598  pp.,  43 
pi.  and  maps;  xv,  646  pp.,  23  pi. ;  xix,  735  pp.,  6  pi. 

XVII.  Seventeenth  Annual  Report  of  the  United  States  Geological  Survey,  1895-'96,  Charles 
D.  Walcott,  Director.  1896.  8°.  3  pt.  in  4  vol.  xxii,  1076  pp.,  67  pi.  and  maps;  xxv,  864  pp.,  113  pi. 
and  maps;  xxiii,  542  pp.,  8  pi.  and  maps;  iii,  .543-1058  pp.,  9-13  pi. 

XVIII.  Eighteenth  Animal  Report  of  the  United  States  Geological  Survey,  1896-'97,  Charles  D. 

1 


II  ADVEETISEMENT. 

Walcott,  Director.  1897.  (Parts  II  and  III,  1898.)  8°.  5  pt.  in  6  vol.  1-440  pp.,  4  pi.  and  maps ;  i-v, 
1-653  pp.,  105  pi.  and  maps:  i-v,  1-861  pp.,  118  pi,  and  maps:  i-x,  1-756  pp.,  102  pi.  and  maps;  i-Xii, 
1-642  pp.,  1  pi. ;  643-1400  pp. 

MONOGEAPHS. 

I.  Lake  Bonneville,  by  Grove  Karl  Gilbert.    1890.    4°.    xx,  438  pp.     51  pi.     Imap.    Price  $1.50. 

II.  Tertiary  History  of  the  Grand  Canon  District,  with  Atlas,  by  Clarence  E.  Dutton,  Capt.,  U.  S.  A. 
1882.     4°.     xiv,  264  pp.     42  pi.  and  atlas  of  24  sheets  folio.     Price  $10.00. 

III.  Geology  of  the  Comstook  Lode  and  the  Washoe  District,  with  Atlas,  by  George  F.  Becker. 
1882.     4°.     XV,  422  pp.     7  pi.  and  atlas  of  21  sheets  folio.     Price  $11.00. 

IV.  Comstock  Mining  and  Miners,  by  Eliot  Lord.     1883.     4°.     xiv,  451  pp.     3  pi. '  Price  $1.50. 

V.  The  Copper-Bearing  Eocks  of  Lake  Superior,  by  Eolaud  Dner  Irving.  1883.  4°.  xvi,  464 
pp.     151.     29  pi.  and  maps.     Price  $1.85. 

VI.  Contributions  to  the  Knowledge  of  the  Older  Mesozoic  Flora  of  Virginia,  by  William  Morris 
Fontaine.     1883.     4°.     xi,  144  pp.     54  1.     54  pi.     Price  $1.05. 

VII.  Silver-Lead  Deposits  of  Eureka,  Nevada,  by  Joseph  Storv  Curtis.  1884.  4°.  xiii,  200  pp. 
16  pi.     Price  $1.20. 

VIII.  Paleontology  of  the  Eureka  District,  by  Charles  Doolittle  Walcott.  1884.  4°.  xiii,  298 
pp.    24 1.     24  pi.     Price  $1.10. 

IX.  Brachiopoda  and  Lamellibranchiata  of  the  Earitau  Clays  and  Greensand  Marls  of  New 
Jersey,  by  Eobert  P.  AVhitfield.     1885.     4^^.     xx,  338  pp.     35  pi.     1  map.     Price  $1.15. 

X.  Dinocerata.  A  Monograph  of  an  Extinct  Order  of  Gigaiitic  Mammals,  by  Othniel  Charles 
Marsh.     1886.     4°.     xviii,  243  pp.     56 1.     56  pi.     Price  $2.70. 

XI.  Geological  History  of  Lake  Lahontau,  a  Quaternary  Lake  of  Northwestern  Nevada,  by 
Israel  Cook  Eussell.     1885.     4'-".     xiv,  288  pp.     46  pi.  and  maps.     Price  $1.75. 

XII.  Geology  and  Mining  Industry  of  Leadville,  Colorado,  with  Atlas,  by  Samuel  Franklin 
Emmons.     1886.     i^.    xxix,  770  pp.     45  pi.  and  atlas  of  35  sheets  folio.     Price  $8.40. 

XIII.  Geology  of  the  Quicksilver  Deposits  of  the  Pacific  Slope,  with  Atlas,  by  George  F.  Becker. 
1888.     4°.     xix,  486  pp.     7  pi.  and  atlas  of  14  sheets  folio.     Price  $2.00. 

XIV.  Fossil  Fishes  and  Fossil  Plants  of  the  Triassic  Eocks  of  New  Jersey  and  the  Connecticut 
Valley,  by  John  S.  Newberry.     1888.     4°.     xiv,  152  pp.     26  pi.     Price  $1.00. 

XV.  The  Potomac  or  Younger  Mesozoic  Flora,  by  William  Morris  Fontaine.  1889.  4'^,  xiv, 
377  pp.     180  pi.     Text  and  plates  bound  separately.     Price  $2.50. 

XVI.  The  Paleozoic  Fishes  of  North  America,  by  John  Strong  Newberry.  1889.  4°.  340  pp. 
53  pi.     Price  $1.00. 

XVII.  The  Flora  of  the  Dakota  Group,  a  Posthumous  Work,  by  Leo  Lesquereux.  Edited  by' 
F.  H.  Knowlton.     1891.     4°.     400  pp.     66  pi.     Price  $1.10. 

XVIII.  Gasteropoda  and  Cephaloiioda  of  the  Earitan  Clays  and  Greensand  Marls  of  New  Jersey, 
by  Eobert  P.  Whitfield.     1891.     4°.     402  pp.     50  pi.     Price  $1.00. 

XIX.  The  Penokee  Iron-Bearing  Series  of  Northern  Wisconsin  and  Michigan,  by  Eoland  D. 
Irving  and  C.  E.  Van  Hise.     1892.    4°.     xix,  534  pp.     Price  $1.70. 

XX.  Geology  of  the  Eureka  District,  Nevada,  with  an  Atlas,  by  Arnold  Hague.  1892.  4°  xvii, 
419  pp.     8  pi.     Price  $5.25. 

XXI.  The  Tertiarv  Ehynchophorous  Coleoptera  of  the  United  States,  by  Samuel  Hubbard  Scud- 
der.     1893.     4°.     xi,  206  pp.     12  pi.     Price  90  cents. 

XXII.  A  Manual  of  Topographic  Methods,  by  Henry  Gannett,  Chief  Topographer.  1893.  4°. 
xiv,  300  pp.     18  pi.    Price  $1.00. 

XXIII.  Geology  of  the  Green  Mountains  in  Massachusetts,  by  Eapbael  Pumpelly,  T.  Nelson  Dale, 
and  J.  E.  Wolff.     1894.    4°.     xiv,  206  pp.     23  pi.     Price  $1.30. 

XXIV.  Mollusea  and  Crustacea  of  the  Miocene  Formations  of  New  Jersey,  by  Eobert  Parr  Whit- 
field.    1894.     4°.     193  pp.     24  pi.     Price  90  cents. 

XXV.  TheGlacialLakeAgassiz,  by  Warren  Upham.   1895.   4°.  xxiv,658pp.   38  pi.   Price  $1.70. 

XXVI.  Flora  of  the  Amboy  Clays,  by  John  Strong  Newberry;  a  Pusthumous  Work,  edited  by 
Arthur  Hollick.     1895.    4°.     260  pp.     58  pi.     Price  $1.00. 

XXVII.  Geology  of  the  Denver  Basin  in  Colorado,  by  Samuel  Franklin  Emmons,  Whitman  Cross, 
and  George  Homans  Eldridge.     1896.     4'^.    556  pp.     31  pi.     Price  $1.50. 

XXVIII.  The  Marquette  Iron-Bearing  District  of  Michigan,  with  Atlas,  by  C.  E.  Van  Hise  and 
W.  S.  Bayley,  including  a  Chapter  on  the  Eepublic  Through,  by  H.  L.  Smyth.  1895.  4°.  608  pp.  35 
pi.     Price  $5.75. 

XXIX.  Geology  of  Old  Hampshire  County,  Massachusetts,  comprising  Franklin,  Hampshire,  and 
Hampden  Counties,  by  Benjamin  Kendall  Emerson.     1898.     4°.     xxi,  790  pp.     35  pi.     Price  $1.90. 

XXX.  Fossil  Medusa;, by  Charles  Doolittle  Walcott.     1898.    4o.     ix,201pp.     47  pi.     Price  $1.50. 

In  preparation: 

XXXI.  Geology  of  the  Aspen  Mining  District,  Colorado,  with  Atlas,  by  Josiah  Edward  Spurr. 

XXXII.  Geology  of  the  Yellowstone  National  Park,  Part  II,  Descriptive  Geology,  Pe'trograph y , 
and  Paleontology,  by  Arnold  Hague,  J.  P.  Iddings,  W.  Harvey  Weed,  Charles  D.  Walcott,  G.  H.  Girty, 
T.  W.  Stanton,  and  F.  H.  Knowlton. 

XXXIII.  Geology  of  the  Narragansett  Basin,  by  N.  S.  Shaler,  J,  B.  Woodworth,  and  August  F. 
Foerste. 


ADVERTISEMENT.  Ill 

XXXIV    Tho  Glacial  Gravols  of  Maine  and  their  Associated  Deposits,  Ijy  George  H.  Stone. 
—The  l.atfi-  Kxtinct  Floras  of  North  America,  by  .John  Strong  Newberry;  edited  by  Arthur 

—  Flora  of  the  Lower  Coal  Measures  of  Missonri,  by  David  White. 

—The  Crystal   Falls  Iron-l!earing  District  of  Michigan,  by  .1.  Morgan  Clements  and  Henry 
Lloyd  Snivth ;  with  a  Chapter  on  th(^  Sturgeon  Hiver  Tongue,  by  William  Shirley  Bayley. 
— Sanropcxla,  by  ().  C.  Marsh. 
— Steiiusaiiria,  iiv  O.  C.  Marsh. 

—Mrnntollieriida',  by  O.  C.  Marsh.  ,,,„,. 

—Flora  of  tho  Laramie  and  Allied  Formations,  by  1'  rank  Hall  Kuowlton. 

BULLETINS. 

1  On  Hypersthene-Andesite  and  on  Triclinic  Pyroxene  in  Augitic  Rocks,  by  Whitman  Cross, 
with  a  (Joolog'lcal  Sketch  of  Buffalo  Peaks,  Colorado,  by  S.  P.  Emmons.     1883.     8°.     42  pp.     2  pL 

2  (iolcl  and  Silver  Conversion  Tables,  giving  the  Coining  Values  of  Troy  Ounces  of  Fine  Metal, 
etc.,  computed  by  Albert  Williams,  jr.     1883.     S'^.     8  pp.     Price  .5  cents. 

3  On  the  Fossil  Faunas  of  the  Upper  Devonian,  along  the  Meridian  of  7b°  30',  from  Tompkins 
County',  N.  Y.,  to  Bradford  County,  Pa.,  by  Henry  S.  Williams.     1884.     8°.     36  pp.     Price  5  cents. 

4.  On  Mesozoic  Fossils,  by  Charles  A.  White.     1884.     8".     36  pp.     9  pi.     Price  5  cents. 

5.  A  Dictionary  of  Altitudes  iu  the  United  States,  compiled  by  Henry  Gannett.  1884.  8^.  325 
pp.     Price  20  cents.  ,„  „  .      _ 

6  Eleyations  in  the  Dominion  of  Canada,  by  J.  W.  Spencer.     1884.     8°.     43  pp.     Price  5  cents. 

7  Mapoteca  Geologica  Americana.  A  Catalogue  of  Geological  Maps  of  America  (North  and 
South),  1752-1881,  in  Geographic  and  Chronologic  Order,  by  Jules  Marcou  and  John  Belknap  Marcou. 

1884.  8'^.     184  pp.     Price  10  cents. 

8.  On  Secondary  Enlargements  of  Mineral  Fragments  in  Certain  Rocks,  by  R.  D.  Irving  and 
C.  R.  VauHise.     1884.     8'^.     58  pp.      6  pi.     Price  10  cents. 

9  A  Report  of  Work  done  in  tho  Washington  Laboratory  during  the  Fiscal  Year  1883-84.  F.  W. 
Clarke,  Chief  Chemist;  T.M.Chatard,  Assistant  Chemist.     1884.     8°.     40  pp.     Price  5  cents. 

10.  On  the  Cambrian  Faunas  of  North  America.  Preliminary  Studies,  by  Charles  Doolittle 
Waleott.     1884.     8°.     74  pp.     10  pi.     Price  5  cents. 

11.  On  the  Quaternary  and  Recent  Mollusca  of  the  Great  Basin;  with  Description  of  New 
Forms,  by  R.  Ellsworth  Call!  Introduced  by  a  Sketch  of  the  Quaternary  Lakes  of  the  Great  Basin, 
by  G.  K.  Gilbert.     1884.     8°.     66  pp.     6  pi.     Price  5  cents. 

12.  A  Crystallographic  Study  of  the  Thinolite  of  Lake  Lahontan,  by  Edward  S.Dana.     1884.    8°. 

34  pp.     3  pi.     Price  5  cents. 

13.  Boundaries  of  tho  United  States  and  of  the  Several  States  and  Territories,  with  a  Historical 
Sketch  of  the  Territorial  Changes,  by  Henry  Gannett.     1885.    8°.     135  pp.     Price  10  cents. 

14.  The  Electrical  and  Magnetic  Properties  of  the  Iron-Carburets,  by  Carl  Barus  and  Vincent 
Strouhai.     1885.     8°.    238  pp.     Price  15  cents. 

15.  On  the  Mesozoic  and  Cenozoic  Paleontology  of  California,  by  Charles  A.  White.  1885.  8°. 
33  pp.     Price  5  cents. 

16.  OntheHigherDevoniauFaunasofOntarioCounty,  New  York,  by  John  M.Clarke.     1885.     8°. 

86  pp.     3  pi.     Price  5  cents. 

17.  On  the  Development  of  Crystallization  in  the  Igneous  Rocks  of  Washoe,  Nevada,  with  Notes 
on  the  Geology  of  the  District,  by  Arnold  Hague  and  Joseph  P.  Iddings.  1885.  8°.  44  pp.  Price  5 
cents. 

18.  On  Marine  Eocene,  Fresh- Water  Miocene,  and  other  Fossil  Mollusca  of  Western  North 
America,  by  Charles  A.  White.     1885.    8".     26  pp.     3  pi.     Price  5  cents. 

19.  Notes  on  the  Stratigraphy  of  California,  by  George  F.Becker.   188.5.   8°.   28  pp.   Price  5  cents. 

20.  Contributions  to  the  Mineralogy  of  the  Rocky  Mountains,  by  Whitman  Cross  and  W.  F.  Hille- 
brand.     1885.     8*^.     114  pp.     1  pi.     Price  10  cents. 

21.  The  Lignites  of  the  Great  Sioux  Reservation;  a  Report  on  tho  Region  between  the  Grand 
and  Moreau  Rivers,  Dakota,  by  Bailey  Willis.     1885.     8°.     16  pp.     5  pi.     Price  5  cents. 

22.  On  New  Cretaceous  Fossils  from  California,  by  Charles  A.  White.  1885.  8°.  25  pp.  5  pL 
Price  5  cents. 

23.  Observations  on  the  Junction  between  the  Eastern  Sandstone  and  the  Keweenaw  Series  on 
KeweenawPoint,  Lake  Superior,  by  R.  D.  Irving  and  T.  C.  Chamberlin.  1885.  8=.  124  pp.  17  pi. 
Price  15  cents. 

24.  List  of  Marine  Mollusca,  comprising  the  Quaternary  Fossils  and  Recent  Forms  from  American 
Localities  between  Cape  Hatteras  and  Cape  Roque,  including  the  Bermudas,  by  AVilliam  Healey  Dall. 

1885.  8°.     336  pp.     Price  25  cents. 

25.  The  Present  Technical  Condition  of  the  Steel  Industry  of  the  United  States,  by  Phmeas 
Barnes.     1885.     8°.    85  pp.     Price  10  cents. 

26.  Copper  Smelting,  by  Henry  M.  Howe.     1885.     8°.     107  pp.     Price  10  cents. 

27.  Report  of  Work  done  in  the  Division  of  Chemistry  and  Physics,  mainly  during  the  Fiscal  Year 
1884-'85.     1886.     8°.     80  pp.     Price  10  cents. 

28.  The  Gabbros  and  Associated  Hornblende  Rocks  occurring  iu  the  Neighborhood  of  Baltimore, 
Maryland,  by  George  Huntington  Williams.     1886.     8°.     78  pp.     4  pi.    Price  10  cents. 


IV  ADVERTISEMENT. 

29.  On  tlie  Fresh- water  Invertebrates  of  tie  North  American  Jurassic,  hyCharlea  A.  White.  1886. 
8*^.    41  pp.     4  pi.     Price  5  cents. 

30.  Second  Contribution  to  the  Studies  on  the  Cambrian  Faunas  of  North  America,  by  Charles 
Doolittle  Walcott.     1886.     8".     369  pp.     33  pi.     Price  25  cents. 

31.  Systematic  Review  of  our  Present  Knowledge  of  Fossil  Insects,  including  Myriapods  and 
Arachnids,  by  Samuel  Hubbard  Scudder.     1886.     8°.     128  pp.     Price  15  cents. 

32.  Lists  and  Analyses  of  the  Mineral  Springs  of  the  United  States ;  a  Preliminary  Study,  by 
Albert  C.  Peale.     1886.     8°.     235  pp.     Price  20  cents. 

33.  Notes  on  the  Geology  of  Northern  California,  by  J.  S.Diller.     1886.    8°.    23  pp.    Price  5  cents. 

34.  On  the  Relation  of  the  Laramie  Molluscau  Fauna  to  that  of  the  Succeeding  Fresh-Water  Eocene 
and  Other  Groups,  by  Charles  A.  White.     1886.     8°.     54  pp.     5  pi.     Price  10  cents. 

35.  Physical  Properties  of  the  Iron-Carburets,  by  Carl  Barus  and  Vincent  Strouhal.  1886.  8'^\ 
62  pp.     Price  10  cents. 

36.  SubsidenceofFineSolidParticlesiuLiquidSjbyCarlBarus.    1886.    8°.    58pp.    Price  10 cents. 

37.  Types  of  the  Laramie  Flora,  by  Lester  F.  Ward.     1887.     8°.     354  pp.     57  pi.     Price  25  cents. 

38.  PeridotiteofElliottCounty,Kentucky,byJ.S.DiUer.     1887.     8-^.    31pp.    Ipl.    Price5cents. 

39.  The  Upper  Beaches  and  Deltas  of  the  Glacial  Lake  Agassiz,  by  Warren  Upham.  1887.  8°. 
84  pp.     1  pi.     Price  10  cents. 

40.  Changes  in  River  Courses  in  Washington  Territory  due  to  Glaciation,  by  Bailey  Willis.  1887. 
8°.     10  pp.     4  pi.     Price  5  cents. 

41.  On  the  Fossil  Faunas  of  the  Upper  Devonian — the  Genesee  Section,  New  York,  by  Henry  S. 
WiUiams.     1887.     8°.     121  pp.     4  pi.     Price  15  cents. 

42.  Reportof  Work  done  in  the  Division  of  Chemistry  and  Physics,  mainly  during  the  Fiscal  Year 
1885-'86.     F.  W.  Clarke,  Chief  Chemist.     1887.     8".     152  pp.     1  pi.     Price  15  cents. 

43.  Tertiary  and  Cretaceous  Strata  of  the  Tuscaloosa,  Tombigbee,  and  Alabama  Rivers,  by  Eugene 
A.  Smith  and  Lawrence  C.  Johnson.     1887.     8°.     189  pp.     21  pi.     Price  15  cents. 

44.  Bibliography  of  North  American  Geology  for  1886,  by  Nelson  H.  Darton.  1887.  8°.  35  pp. 
Price  5  cents. 

45.  The  Present  Condition  of  Knowledge  of  the  Geology  of  Texas,  by  Robert  T.  Hill.  1887.  8°. 
94  pp.     Price  10  cents. 

46.  Nature  and  Origin  of  Deposits  of  Phosphate  of  Lime,  by  R.  A.  F.  Penrose,  jr.,  with  an  Intro- 
duction by  N.  S.  Shaler.     1888.     8°.     143  pp.     Price  15  cents. 

47.  Analyses  of  Waters  of  the  Yellowstone  National  Park,  with  an  Account  of  the  Methods  of 
Analysis  employed,  by  Frank  Austin  Gooch  and  James  Edward  Whitiield.  1888.  8°.  84  pp.  Price 
10  cents. 

48.  On  the  Form  and  Position  of  the  Sea  Level,  by  Robert  Simpson  Woodward.  1888.  8°.  88 
pp.     Price  10  cents. 

49.  Latitudes  and  Longitudes  of  Certain  Points  in  Missouri,  Kansas,  and  New  Mexico,  by  Robert 
Simpson  Woodward.     1889.     8°.     133  pp.     Price  15  cents. 

50.  Formulas  and  Tables  to  Facilitate  the  Construction  and  Use  of  Maps,  by  Robert  Simpson 
Woodward.     1889.     8°.     124  pp.     Price  15  cents. 

51.  On  Invertebrate  Fossils  from  the  Pacific  Coast,  by  Charles  Abiathar  White.  1889.  8°.  102 
pp.     14  pi.     Price  15  cents. 

52.  Subaerial  Decay  of  Rocks  and  Origin  of  the  Red  Color  of  Certain  Formations,  by  Israel 
Cook  Russell.     1889.     8°.     65  pp.     5  pi.     Price  10  cents. 

53.  The  Geology  of  Nantucket,  by  Nathaniel  Southgate  Shaler.  1889.  8°.  55  pp.  10  pi.  Price 
10  cents. 

54.  On  the  Thermo-Electric  Measurement  of  High  Temperatures,  by  Carl  Barus.  1889.  8°. 
313  pp.,  incl.  1  pi.     11  pi.    Price  25  cents. 

55.  Report  of  Work  done  in  the  Division  of  Chemistry  and  Physics,  mainly  during  the  Fiscal 
Year  1886-'87.     Frank  Wigglesworth  Clarke,  Chief  Chemist.     1889.     8°.     96  pp.     Price  10  cents. 

56.  Fossil  Wood  and  Lignite  of  the  Potomac  Formation,  by  Frank  Hall  Knowlton.  1889.  8°. 
72  pp.     7  pi.     Price  10  cents. 

57.  A  Geological  Reconnoissance  in  Southwestern  Kansas,  by  Robert  Hay.  1890.  8°.  49  pp. 
2  pi.     Price  5  cents. 

58.  The  Glacial  Boundary  in  Western  Pennsylvania,  Ohio,  Kentucky,  Indiana,  and  Illinois,  by 
George  Frederick  Wright,  with  an  Introduction  by  Thomas  Chrowder  Chamberlin.  1890.  8°.  112 
pp.,  incl.  1  pi.     8  pi.     Price  15  cents. 

59.  The  Gabbros  and  Associated  Rocks  in  Delaware,  by  Frederick  D.  Chester.  1890.  8°.  45 
pp.     1  pi.     Price  10  cents. 

60.  Report  of  Work  done  in  the  Division  of  Chemistry  and  Physics,  mainly  during  the  Fiscal 
Year  1887-'88.     F.  W.  Clarke,  Chief  Chemist.     1890.     8°.     174  pp.     Price  15  cents. 

61.  Contributions  to  the  Mineralogy  of  the  Pacific  Coast,  by  William  Harlow  Melville  and  Wal- 
demar  Lindgron.     1890.    8°.     40  pp.     3  pi.     Price  5  cents. 

62.  The  Greenstone  Schist  Areas  of  the  Menominee  and  Marquette  Regions  of  Michigan,  a  Con- 
tribution to  the  Subject  of  Dynamic  Metamorphism  in  Eruptive  Rocks,  by  George  Huntington  Williams, 
with  .an  Introduction  by  Roland  Duer  Irving.     1890.     8°.     241  pp.     16  pi.     Price  30  cents. 

63.  A  Bibliography  of  Paleozoic  Crustacea  from  1698  to  1889,  including  a  List  of  North  Amer- 
ican Species  and  a  Systematic  Arrangement  of  Genera,  by  Anthony  W.  Vogdes.  1890.  8°.  177  pp. 
Price  15  cents. 


ADVERTISEMENT.  V 

6-1.  A  Rtiport  of  Work  dono  in  tho  Division  of  Chemistry  and  Pliysirs,  mainly  during  the  Fiscal 
Year  IHSH-'Sil.     !•'.  \V.  ClarUo,  CliicrCilicuiist.     IWIO.     S' \     CO  ]i]i.     I'l-ico  U)  cents. 

t!").  Stiali;;ra])hy  of  tlie  liitMUiinons  Coal  Field  of  Pennsylvania,  Ohio,  and  West  Virginia,  by 
Israel  C.  Wliit<>r    Wfl.     «".     212  p)!.     U  pi.     Price  20  cents. 

{)(i.  On  a  (Sroiip  of  Volcanic  Kocks  from  the  Tcwau  Mountains,  New  Mexico,  and  on  the  Occur- 
rence of  Primary  Quartz  in  Certain  Basalts,  hy  Joseph  Paxsou  Iddiugs.     1890.     8°.     34  pp.     Price  5 

cents. 

67.  The  Relations  of  the  Traps  of  tho  Newark  System  in  the  New  Jersey  Region,  by  Nelson 
Horatio  Darton.     1«I0.     8^'.     82  pji.     Price  10  cents. 

68.  Earthquakes  in  California  in  1889,  by  James  Edward  Kceler.     1890.     8°.     25  pp.     Price  5 

cents. 

69.  A  Classed  and  Annotated  Biography  of  Fossil  Insects,  by  Samuel  Howard  Scudder.  1890. 
8°.     101pp.     Price  15  cents. 

70.  A  Report  on  Astronomical  AVork  of  1889  and  1890,  by  Robert  Simpson  Woodward.  1890.  8°. 
79  pp.     Price  10  cents. 

71.  Index  to  the  Known  Fossil  Insects  of  the  World,  including  Myriapods  and  Arachnids,  by 
Samncl  Hubbard  Scudder.     1891.     8".     744  i)p.     Price  50  cents. 

72.  Altitudes  between  Lake  Superior  and  the  Rocky  Mountains,  by  Warren  Upham.  1891.  8°. 
229  pp.     Pri<e  20  cents. 

73.  Tlic  Viscosity  of  Solids,  by  Carl  Barns.     1891.     8'^.     xii,  139  pp.     6  pi.     Price  15  cents. 

74.  The  Minerals  of  North  Carolina,  by  Frederick  Augustus  Genth.  1891.  8°.  119  pp.  Price 
15  cents. 

75.  Record  of  North  American  Geology  for  1887  to  1889,  inclusive,  by  Nelson  Horatio  Darton. 
1891.     8^'.     173  pp.     Price  15  cents. 

76.  A  Dii'tionary  of  Altitudes  in  the  United  States  (Second  Edition),  compiled  by  Henry  Gannett, 
Chief  Topographer.     1891.     8°.     393  pp.     Price  25  cents. 

77.  The  Texan  Permian  and  its  Mesozoio  Types  of  Fossils,  by  Charles  A.  White.  1891.  8°.  51 
pp.     4  pi.     I'rice  10  cents. 

78.  A  Report  of  Work  done  in  the  Division  of  Chemistry  and  Physios,  mainly  during  the  Fiscal 
Year  1889-'90.     F.  W.  Clarke,  Chief  Chemist.     1891.     8".     131  pp.     Price  15  cents. 

79.  A  Late  Volcanic  Eruption  in  Northern  California  and  its  Peculiar  Lava,  by  .J.  S.  Diller. 

80.  Correlation  Papers — Devonian  and  Carboniferous,  by  Henry  Shaler  Williams.  1891.  8°. 
279  pp.     Price  20  cents. 

81.  Correlation  Papers— Cambrian,  by  Charles  Doolittle  AValcott.     1891.     8°.     547  pp.     3  pi. 

82.  Correlation  Papers— Cretaceous,  by  Charles  A.  White.  1891.  8'^.  ."^73  pp.  3  pi.  Price  20 
cents. 

83.  Correlation  Papers— Eocene,  by  William  Bullock  Clark.  1891.  8°.  173  pp.  2  pi.  Price 
15  cents. 

84.  Correlation  Papers— Neocene,  by  W.  H.  Dall  and  G.  D.  Harris.     1892.     8^.     349  pp.     3  pi. 

85.  Correlation  Papers— The  Newark  System,  by  Israel  Cook  Russell.  1892.  8°.  344  pp.  13  pL 
Price  25  cents. 

86.  Correlation  Papers — Archean  and  Algonkian,  by  C.  R.  VanHise.  1892.  8^.  549  pp.  12  pi. 
Price  25  cents. 

87.  A  Synopsis  of  American  Fossil.  Brachiopoda,  including  Bibliography  and  Synonymy,  by 
Charles  Schuc'hert.     1897.     8".     464  pp.     Price  30  cents. 

88.  The  Cretaceous  Foraminifera  of  New  Jersey,  by  Rufus  Mather  Bagg,  Jr.  1898.  8°.  88  pp. 
6  pi.     Price  10  cents. 

89.  Some  Lava  Flows  of  the  Western  Slope  of  the  Sierra  Nevada,  California,  by  F.  Leslie 
Ransome.     1898.     8°.     74  pp.     11  pi.     Price  15  cents. 

90.  A  Report  of  Work  done  in  the  Division  of  Chemistry  and  Physics,  mainly  during  the  Fiscal 
Year  1890-'91.     F.  W.  Clarke,  Chief  Chemist.     1892.    8°.     77  pp.     Price  10  cents. 

91.  Record  of  North  American  Geology  for  1890,  by  Nelson  Horatio  Darton.  1891.  8°.  88  pp. 
Price  10  cents. 

92.  The  Compressibility  of  Liquids,  by  Carl  B.irus.     1892.     8°.     96  pp.     29  pi.     Price  10  cents. 

93.  Some  Insects  of  Special  Interest  from  Florissant,  Colorado,  and  Other  Points  in  the  Tertiaries 
of  Colorado  and  Utah,  by  Samuel  Hubbard  Scudder.     1892.    8^^.     35  pp.     3  jil.     Price  5  cents. 

94.  The  Mechanism  of  Solid  Viscosity,  by  Carl  Barus.     1892.     8°.     138  pp.     Price  15  cents. 

95.  Earthquakes  in  California  in  1890  and  1891,  by  Edward  Singleton  Holden.  1892.  8°.  31pp. 
Price  5  cents. 

96.  The  Volume  Thermodvnamics  of  Liquids,  by  Carl  Barus.     1892.     8'^.     100  pp.     Price  10  cents. 

97.  The  Mesozoic  Echinodermata  of  the  United  States,  by  W.  B.  Clark.  1893.  8°.  207  pp.  .50pl. 
Price  20  cents. 

98.  Flora  of  the  Outlying  Carboniferous  Basins  of  Southwestern  Missouri,  by  David  White. 
1893.    S'^.     139  pp.    5  pi.     Price  15  cents. 

99.  Record  of  North  American  Geology  for  1891,  by  Nelson  Horatio  Darton.  1892.  8°.  73  pp. 
Price  10  cents. 

100.  Bibliography  and  Index  of  the  Publications  of  the  U.  S.  Geological  Survey,  1879-1892,  by 
Philip  Creveling  Warman.     1893.     8°.     495  pp.     Price  25  cents. 

101.  Insect  Fauna  of  the  Rhode  Island  Coal  Field,  by  Samuel  Hubbard  Scudder.  1893.  8°. 
27  pp.    2  pi,    Price  5  cents. 


VI  ADVERTISEMENT. 

102.  A  Catalogue  and  Bibliography  of  North  American  Mesozoic  Invertebrata,  by  Cornelius 
Breckinridge  Boyle.     1892.     8°.     315  pp.     Price  25  cents. 

103.  High  Temperature  Work  in  Igneous  Fusion  and  Ebullition,  chiefly  in  Relation  to  Pressure, 
by  Carl  Barus.     1893.     8°.     57  pp.     9  pi.     Price  10  cents. 

104.  Glaciation  of  the  Yellowstone  Valley  north  of  the  Park,  by  Walter  Harvey  Weed.    1893.    8°. 
41  pp.     4  pi.     Price  5  cents. 

105.  The  Laramie  and  the  Overlying  Livingstone  Formation  in  Montana,  by  Walter  Harvey 
Weed,  with  Report  on  Flora,  by  Frank  Hall  Knowlton.     1893.     8°    68  pp.     6  pi.     Price  10  cents. 

106.  The  Colorado  Formation  and  its  Invertebrate  Fauna,  by  T.  W.  Stanton.     1893.     8°.     288 
pp.    45  -pi.     Price  20  cents. 

107.  The  Trap  Dikes  of  the  Lake  Champlaiu  Region,  by  James  Furman  Kemp  and  Vernon 
Freeman  Mai-sters.     1893.     8^^.     62  pp.     4  pi.     Price  10  cents. 

108.  A  Geological  Reconnoissance  in  Central  Washington,  by  Israel  Cook  Russell.     1893.     8'-'. 
108  pp.     12  pi.     Price  15  cents, 

109.  The  Eruptive  and  Sedimentary  Rocks  on  Pigeon  Point,  Minnesota,  and  their  Contact  Phe- 
nomena, by  William  Shirley  Bayley.     1893.     8°.     121  pp.     16  pi.     Price  15  cents. 

110.  The  Paleozoic  Section  in  the  Vicinity  of  Three  Porks,  Montana,  by  Albert  Charles  Peale. 
893.     8°.    56  pp.     6  pi.     Price  10  cents. 

111.  Geology  of  the  Big  Stone  Gap  Coal  Fields  of  Virginia  and  Kentucky,  by  Marius  R.  Camp- 
bell.    1893.     8°.     106  pp.     6  pi.     Price  15  cents. 

112.  Earthquakes  in  California  in  1892,  by  Charles  D.  Perrine.    1893.    8°.    57  pp.    Price  10  cents. 

113.  A  Report  of  Work  done  in  the  Division  of  Chemistrv  during  the  Fiscal  Years  1891-''92  and 
1892-'93.     F.  W.  Clarke,  Chief  Chemist.     1893.     8°.     115  pp.     Price  15  cents. 

114.  Earthquakes  in  California  in  1893,  by  Charles  D.  Perrine.    1894.    8°.    23  pp.    Price  5  cents. 

115.  A  Geographic  Dictionary  of  Rhode  Island,  by  Henry  Gannett.     1894.     8°.     31  pp.     Price 
5  cents. 

116.  A  Geographic  Dictionary  of  Massachusetts,  by  Henry  Gannett.     1894.     8°.     126  pp.     Price 
15  cents. 

117.  A  Geographic  Dictionary  of  Connecticut,  by  Henry  Gannett.     1894.     8°.     67  pp.     Price  10 
cents. 

118.  A  Geographic  Dictionary  of  New  Jersey,  by  Henry  Gannett.     1894.     8°.     131  pp.     Price  15 
cents. 

119.  A  Geological  Reconnoissance  in  Northwest  Wyoming,  by  George  Homans  Eldridge.     1894. 
S°.     72  pp.     Price  10  cents. 

120.  The  Devonian  System  of  Eastern  Pennyslvania  and  New  Y'ork,  by  Charles  S.  Prosser.     1894. 
8".    81  pp.     2  pi.     Price  10  cents. 

121.  A  Bibliography  of  North  American  Paleontology,  by  Charles  Rollin  Keyes.     1894.    8°.     251 
pp.     Price  20  cents. 

122.  Results  of  Primary  Triangiilation,  by  Henry  Gannett.     1894.    8°.     412  pp.     17  pi.     Price 
25  cents. 

123.  A  Dictionary  of  Geographic  Positions,  by  Henry  Gannett.     1895.     8°.     183  pp.     1  pi.    Price 
15  cents. 

124.  Revision  of  North  American  Fossil  Cockroaches,  by  Samuel  Hubbard  Scudder.     1895.     8°. 
176  pp.     12  pi.     Price  15  cents. 

125.  The  Constitution  of   the   Silicates,  by  Frank  Wigglesworth  Clarke.     1895.     8°.     109   pp. 
Price  15  cents. 

126.  A  Mineralogical  Lexicon  of  Franklin,  Hampshire,  and  Hampden  counties,  Massachusetts, 
by  Benjamin  Kendall  Emerson.     1895.     8°.     180  pp.     1  pi.     Price  15  cents. 

127.  Catalogue  and  Index  of  Contributions  to  North  American  Geology,  1732-1891,  by  Nelson 
Horatio  Darton.     1896.    8°.     1045  pp.     Price  60  cents. 

128.  The  Bear  River  Formation  and  its  Characteristic  Fauna,  by  Charles  A.  White.     1895.    8°. 
108  pp.     11  pi.     Price  15  cents. 

129.  Earthquakes  in  California  in  1894,  by  Charles  D.  Perrine.    1895.     8°.     25  pp.     Price  5  cents. 

130.  Bibliography  and  Index  of  North  American  Geology,  Paleontology,  Petrology,  and  Miner- 
alogy for  1892  and  1893,  by  Fred  Boughton  Weeks.     1896.     8^.    210  pp.     Price  20  cents. 

131.  Report  of  Progress  of  the  Division  of  Hydrography  for  the  Calendar  Years  1893  and  1894, 
by  Frederick  Haynes  Newell,  Topographer  iu  Charge.     1895.     8°.     126  pp.     Price  15  cents. 

132.  The  Disseminated  Lead  Ores  of  Southeastern  Missouri,  by  Arthur  Winslow.     1896.    8°. 
31  pp.     Price  5  cents. 

133.  Contributions  to  the  Cretaceous  Paleontology  of  the  Pacific  Coast:    The  Fauna  of  tho 
Knoxville  Beds,  by  T.W.  Stanton.     1895.    8°.     132  pp.     20  pL     Price  15  cents. 

134.  The  Cambrian  Rocks  of  Pennsylvania,  by  Charles  Doolittle  Walcott.     1896.     8°.    43  pp. 
15  pi.     Price  5  cents. 

135.  Bibliography  and  Index  of  North  American  Geology,  Paleontology,  Petrology,  and  Miner- 
alogy for  the  Year  1894,  by  F.  B.  AVeeks.     1896.     8*^.     141  pp.     Price  15  cents. 

136.  Volcanic  Rocks  of  South  Mountain,  Pennsylvania,  by  Florence  Bascom.    1896.    8"^.    124  pp. 
28  pi.     Price  15  cents. 

137.  The  Geology  of  the  Fort  Riley  Military  Reservation  and  Vicinity,  Kansas,  by  Robert  Hay. 
1896.    8°.    35  pp.     8  pi.     Price  5  cents. 

138.  Artesian-well  Prospects  iu  the  Atlantic  Coastal  Plain  Region,  by  N.  H.  Darton.     1896.    8°. 
228  pp.     19  pi.     Price  20  cents. 

139.  Geology  of  the  Castle  Mountain  Mining  District,  Montana,  by  W.  H.  Weed  and  L.  V.  Pirs- 
son.     1896.     8'^.     164  pp.     17  pi.     Price  15  cents. 


ADVERTISEMENT.  VII 

ItO    Report  of  ProgreBS  of  the  Division  of  Hydrography  for  the  Calendar  Year  1895,  by  Frederick 

"-"^^^i  li^r^^Sis  ^^UT.S.^:^^^^>^     ;i^^^;^??Maryiand,  and  Virginia, 

.,WiJufn...,n..UC.ari.^^^l^O.  J'.^  Northwestern  Louisiana,  hy 

■'■'^''l^i^^^.^^'oi&.'^r^^e^'^^^^^  1B06.    8o.    lU  pp. 

Price  l^^'^euts^  moraines  of  the  Missouri  Coteau  and  their  Attendant  Deposits,  by  James  Ed^vard  Todd. 
'^'-  ^.'^lj'l:ot^^Fo^^^n^t.Sua.,X>j^.U.Voni^ne.  1896.  8°.  149  pp.  2  pi.  Price 
^^  °*"u6  Biblio-vraphy  and  Index  of  North  American  Geology,  Paleontology,  Petrology,  and  Miner- 
--  ^'^X^i  l^^lH^Sn  iS^by^ha^'S;  pS  l^J^t  Astronomer  iu  Charge 
"^  -S^^'t:ii^fS,^^U,^3^o;;1^t^:f Method  ^^.tod  S^tes 

Geological  ^&',  1880^^^^^^^  ^^^'-    '•     '^'^  l^^''     ^'"'^ 

^^  '""u9    Biblio-raphy  and  Index  of  North  American  Geology,  Paleontology,  Petrology,  and  Miner- 
^Wvff.vX  Ye  rr  1896  by  Fred  Bough  ton  Weeks.     1897.     8°.     152  pp.     Price  15  cents. 
alogy  ("^t]}!^,^«^»ional  Series  of^Eock  Specimens  Collected  and  Distributed  by  the  United  States 
GeoloiealSurveJ;  by  Joseph  Silas  Diller.    1898.    8-.    398  pp.    47  pi.    Price  2o  cents. 

Inpress^^  The  Lower  Cretaceous  Gryphicas  of  the  Texas  Kegion,  by  R.  T.  Hill  and  T.  Wayland 
^^'^.  A  cftalogue  ol^t^'be  Scerutrnd  Te^xtary  Plants  of  North  America,  by  F.  H.  Knowlton. 
^^^^'  153.  A  Bil.liogmphio  Ind;x.of  North  American  Carboniferous  InYortebrates,  by  Stuart  Weller. 
1898.    8°.        pp.    Price    cents. 

WATER-SUPPLY  AND  IRRIGATION  PAPERS. 

By  act  of  Congress  approved  June  11, 1896,  the  following  provision  was  inade:  „^„   .„„    . 

^Provided,  That  hereafter  the  reports  of  the  Geolosical  Survey  in  relation  to  the  gauging  of 
streams  and  to  the  methods  of  utilizing  the  water  resources  may  be  prin'  ed  m  octavo  form  not  to 
exceed  onrhundred  pa^es  in  length  and  live  thousand  copies  m  number;  ouethousana  copies  of  ^  ycli 
shall  be  for  the  official'use  of  the  Geological  Survey,  one  thousand  five  hundred  copie^  shall  he  ddiv- 
ered  to  the  Senate,  and  two  thousand  five  hundred  copies  shall  be  delivered  to  the  House  of  Repre- 
sentatives, for  distribution."  . 

Under  this  law  the  following  papers  have  been  issued: 

1.  Pumping  Water  for  Irrigation,  by  Herbert  M.  V  ilson.     1896.     8^.    57  pp.     9  pi. 

2.  Irrigation  near  Phceuix,  Arizona,  by  Arthur  P.  Davis.     1897.     8-.     9/  pp.     31  pi. 

3.  Sewage  Irrigation,  by  George  W.  Rafter.     1897.     f.     100pp.     4pl 

4.  ARec^onnoissancein  Southeastern  Washington,  by  Israel  Cook  Russell     1897.    8°.    96  pp.    7  p  . 

5.  Irrigation  Practice  on  the  Great  Plains,  by  Elias  Jranson  Cowgill.     1897.     8°.     39  pp.     l.^p  . 

6.  Underground  Waters  of  Southwestern  Kansas,  by  Erasmus  Haworth.    1897.    8  .    65  pp.    l^  pi. 

7.  Seepage  Waters  of  Northern  Utah,  by  Samuel  Fortier.     1897      8^-.     50  pp.     dpi. 

8.  Windmills  for  Irrigation,  by  Edward  Charles  Murphy.     1897      S'^.    49  pp.    8  pi. 

9.  Irrigation  near  Greeley,  Colorado,  by  David  Boyd.     1897.     8^-90  pp.    21  pi. 

10.  Irrigation  in  Mesilla  Valley,  New  Mexico,  by  F.  C.  Barker.    1898.     8°.     ol  pp.     11  pi. 

11.  River  Heights  for  1896,  by  Arthur  P.  Davis.    1897.    8°.    100  pp. 

^"^"'l2.'Water  Resources  of  Southeastern  Nebraska,  by  Nelson  H.Darton.     1898.     8°.     55  pp.     21  pi. 

13.  Irrigation  Systems  in  Texas,  by  William  Ferguson  Hutson.    1898.     8.    .67  pp.     10  pi. 

14.  New  Tests  of  Certain  Pumps  and  Water-Lifts  used  m  Irrigation,  by  Ozni  P.  Hood.    1889.    8  . 

^^15.  Operations  at  River  Stations,  1897,  Part  I.     1898.     8^.     100  pp. 
16.  Operations  at  River  Stations,  1897,  Part  II.    1898.    8°.    101-200  pp. 

TOPOGRAPHIC  MAP  OF  THE  UNITED  STATES. 

When,  in  1882,  the  Geological  Survey  was  directed  by  law  to  make  a  geologic  map  of  the  United 
States  there  was  in  existence  no  suitable  topographic  map  to  serve  a^s  a  base  for  the  geologic  map. 
The  preparation  of  such  a  topographic  map  was  therefore  immediately  begun.  About  one-hth  ot  the 
area  of  the  countrv,  excluding  Alaska,  has  now  been  thus  mapped.  The  map  is  published  in  atlas 
sheets,  each  sheet  representing  a  small  quadrangular  district,  as  explained  under  the  following  head- 
ine  The  separate  sheets  are  sold  at  5  cents  each  when  fewer  than  100  copies  are  purchased,  but  whmi 
thev  are  ordered  in  lots  of  100  or  more  copies,  whether  of  the  same  sheet  or  of  difterent  sheets,  the 
priie  is  2  cents  each.  The  mapped  areas  are  widely  scattered,  nearly  every  State  being  represented. 
More  than  800  sheets  have  been  engraved  and  printed;  they  are  tabulated  by  States  m  tbe  burvey  s 
"List  of  Publications,"  a  pamphlet  which  may  be  had  on  application. 


vni 


ADVEETISEMENT. 


GEOLOGIC  ATLAS  OF  THE  UNITED  STATES. 

The  Geologic  Atlas  of  die  United  States  is  the  final  form  of  publication  of  the  topographic  and 
geologic  maps.  The  atlas  is  issued  in  parts,  progressively  as  the  surveys  are  extended,  and  is  designed 
ultimately  to  cover  the  entire  country. 

Under  the  plan  adopted  the  entire  area  of  the  country  is  divided  into  small  rectangular  districts 
(designated  quadrangles),  bounded  by  certain  meridians  and  parallels.  The  unit  of  survey  is  also  the 
unit  of  publication,  and  the  maps  and  descriptions  of  each  rectangular  district  are  issued  as  a  folio  of 
the  Geologic  Atlas. 

Each  folio  contains  topographic,  geologic,  economic,  and  structural  maps,  together  with  textual 
descriptions  and  explanations,  and  is  designated  by  the  name  of  a  principal  town  or  of  a  prominent 
natural  feature  within  the  district. 

Two  forms  of  issue  have  been  adopted,  a  "library  edition"  and  a  "field  edition."  In  both  the 
sheets  are  bound  between  heavy  paper  covers,  but  the  library  copies  are  permanently  bound,  while 
the  sheets  and  covers  of  the  field  copies  are  only  temporarily  wired  together. 

Under  the  law  a  copy  of  each  folio  is  sent  to  certain  public  libraries  and  educational  institu- 
tions. The  remainder  are  sold  at  25  cents  each,  except  such  as  contain  an  unusual  amount  of  matter, 
which  are  priced  accordingly.  Prepayment  is  obligatory.  The  folios  ready  for  distribution  are  listed 
below. 


No. 


Name  of  sheet. 


State. 


Limiting  meridians. 


Limiting  parallels. 


Area,  in  [Price, 
square 
miles,     cents. 


11 


29 


1  Livingston 

2  Einggold 

3  Plaoerville 

4  Kingston 

5  Sacramento 

6  Chattanooga 

7  Pikes  Peak  (out  of  stock) . . 

8  Sewanee 

9  Anthracite-Crested  Butte  . 
I 

10     Harpers  Ferry 


Montana. 
'Georgia. 


Jackson  . 


Eatillville  . 


Fredericksburg . 

Staunton 

Lassen  Peak 

Knoxville 


Marys  ville.. 
Smartsville . 


Stevenson  . 


Tennessee 

California 

Tennessee 

California 

Tennessee 

Colorado 

Tennessee 

Colorado 

(Virginia 
West  Virginia . 
Maryland 

Caliibrnia 

{Virginia ^ 
Kentucky > 
Tennessee J 

/Maryland \ 

\Virginia J 

/Virginia \ 

tWest  Virginia . .  / 

California 

(Tennessee \ 

\North  Carolina  .  J 

California 

California 

[Alabama ] 

^Georgia > 

iTennessee :J 

Tennessee 

Tennessee 

Tennessee 


Cleveland 

Pikeville 

McMinnviUe 

^r      ■    •  /Marvl.and 

l^o™"' {Virginia 

Three  Forks 

Loudon 


Pocahontas . . 
Morristown.. 


Piedmont. 


Nevada  City. 


/Xellowstone 
tional  Park 


ity-1 
ley- ) 
ill  .) 


Pyramid  Peak . 

Franklin 

Brieeville 

Buckbannon... 

Gadsden 

Pueblo 

Downieville  ... 
Truckee 


[Nevada  City 

..< Grass  Valley 

iBanner  Hili 

{Gallatin 
Canyon... 
Shoshone. 
Lake 


Montana 

Tennessee 

Virginia 

AVest  Virginia  - . 
Tennessee 

(Virginia 
Maryland 
"West  Virginia.. 

California 


Wyoming  , 


California 

(Virginia 

tWest  Virginia  - 

Tennessee 

West  Virginia 

Alabama 

Colorado 

California 

California 


121°  00' 
121°  01' 
120°  57' 


110°-111° 
850-85°  30' 

120°  30'-121o 
84°  3ll'-850 

1210-121°  ;io' 
io°-Ki°   30' 

1050-105°  30' 

85°  30'-86o 

106°  45'-107°  15' 

77°  30'-78° 

120°  30'-121o 

82°  30'-83° 

770.770  30' 

79°-79°  30' 

1210-1220 

830  30'-84o 

1210  30'-122° 
1210-121°  30' 


84°  30'-85o 
850-850  30' 
85°  30'-86° 

76°  30'-77° 

1110-1120 

84°-81°  30' 

81°-81°  30' 
830-83°  30' 

790-79°  30' 

25"-121o  03'  45" 
35"-121o  05'  04" 
05"-121°  00'  25" 


120°-120o  30' 

79°-79°  30' 

84°-84°  30' 

80°-80°  30' 

86°-86o  30' 

104°  30'-105o 

1200  30'-121° 

120°-120o  30' 


450-46° 

340  30'-35o 

38°  30'-39o 
350  30'-36° 
38°  30'-39° 
35°-3.->o  30' 
38°  30'-39° 
350-35°  30' 
38°  45'-39° 

39°-390  30' 

38°-38°  30' 

36°  30'-37o 

380-380  30' 

380-380  30' 
400-41° 
350  30'-36o 
390-390  30' 
39°-39°  30' 


35°-35o  30' 
350  30'-36° 
36°  30'-36° 

38°-38°  30' 

450-46° 
350  30'-36° 
370.370  30' 
360-36°  30' 


39°  13'  50"-39-)  17'  16" 
39°  10'  22"-390  13'  50" 
39°  13'  50"-39o  17'  16" 

440-45° 


38°  30'- 

-39° 

36°-36° 

30' 

38°  30' 

-390 

340-340  30'  1 

38°-38° 

30' 

39°  30'-40° 

39°-39°  30' 

,354 

980 

932 
969 
932 
975 
932 
975 
465 


957 

938 

938 

3,634 

925 

925 
925 


975 
969 
969 

938 

3.354 
969 

951 

963 

925 

11.65 
12.09 
11.65 

3,412 

932 

932 

963 
932 
986 
938 
919 
925 


25 

25 

25 
25 
25 
25 
25 
25 
50 

25 

25 


25 

25 

25 

25 
25 


25 
25 
25 

25 

60 
25 

25 

25 


50 


75 

25 

25 

25 
25 
25 
60 
2.-) 
25 


ADVERTISEMENT.  IX 

STATISTICAL  PAPERS. 

Mineral  Rosourcos  of  the  United  States  [1882],  liy  Albert  WillianiB,  jr.  1883.  8'^.  xvii,  813  pp. 
Price  5(1  conts. 

Mineral  KosourccH  of  tlio  Uiutcd  States,  1883  and  1884,  by  Albert  WiDiams,  jr.  1885.  8".  xiv, 
1016  pp.     Trice  (!()  cents. 

Mineral  Ixosonrccs  (if  the  United  States,  1885.  Division  of  Mining  Statistii-s  and  Technology. 
1886.     y--'.     vii,  576  jip.     Trice  40  cents. 

Mineral  Resources  of  the  United  States,  1886,  by  David  T.  Day.  1887.  8°.  viii,  813  pp.  Price 
(50  cents. 

Mineral  Resources  of  the  United  States,  1887,  by  David  T.  Day.  1888.  8°.  vii,  832  pp.  Price 
50  cents. 

aiineral  Resources  of  the  United  States,  1888,  by  David  T.  Day.  1890.  8°.  vii,  652  pp.  Price 
50  conts. 

Mineral  Resources  of  the  United  States,  1889  and  1890,  by  David  T.  Day.  1892.  8°.  viii,  671  pp. 
Price  50  cents. 

Mineral  Resources  of  the  United  States,  1891,  by  David  T.  Day.  1893.  8°.  vii,  630  pp.  Price 
50  cents. 

Mineral  Resources  of  the  United  States,  1892,  by  David  T.  Day.  1893.  8°.  vii,  850  pp.  Price 
50  cents. 

Mineral  Resources  of  the  United  States,  1893,  by  David  T.  Day.  1894.  8°.  viii,  810  pp.  Price 
50  cents. 

On  March  2, 189.5,  the  following  provision  was  included  in  an  act  of  Congress: 

"Provided,  That  hereafter  the  report  of  the  mineral  resources  of  the  United  States  shall  be 
issued  as  a  part  of  the  report  of  the  Director  of  the  Geological  Survey." 

In  compliance  with  this  legislation  the  following  reports  have  been  published: 

Mineral  Resources  of  the  United  States,  1894,  David  T.  Day,  Chief  of  Division.  1895.  8°.  xv, 
646  pp.,  23  pi. ;  six,  735  pp..  6  pi.     Being  Parts  III  and  IV  of  the  Sixteenth  Annual  Report. 

Mineral  Resources  of  the  United  States,  1895,  David  T.  Day,  Chief  of  Division.  1896.  8°. 
xxiii,  .542  pp.,  8  pi.  and  maps ;  ill,  543-1058  pp.,  9-13  pi.  Being  Part  III  (in  2  vols.)  of  the  Seventeenth 
Annual  Report. 

Mineral  Resources  of  the  United  States,  1896,  David  T.  Day,  Chief  of  Division.  1897.  8°. 
xii,  642  pp.,  Ipl.;  643-1400  pp.     Being  Part  V  (in  2  vols.)  of  the  Eighteenth  Annual  Report. 

The  report  on  the  mineral  resources  for  the  calendar  year  1897  will  form  a  part  of  the  Nineteenth 
Annual  Report  of  the  Survey. 

The  money  received  from  the  sale  of  the  Survey  publications  is  deposited  in  the  Treasury,  and 
the  Secretary  of  that  Department  declines  to  receive  bank  cheeks,  drafts,  or  postage  stamps;  all  remit- 
tances, therefore,  must  be  by  money  oedee,  made  payable  to  the  Director  of  the  United  States 
Geological  Survey,  or  in  currency— the  exact  amount.  Correspondence  relating  to  the  publications 
of  the  Survey  should  be  addressed  to 

The  Director, 

United  States  Geological  Survey, 
Washington,  D.  C,  May,  1S98.  V^^ashlngton,  D.  C. 


(Take  this  loaf  out  and  paste  the  separated  titles  upon  throe  of  your  cata- 
logue cards.  The  iirst  and  second  titles  ueed  no  additioo  ;  over  the  third  write 
that  subject  under  wliioli  you  would  place  the  book  in  your  library.] 


LIBRARY  CATALOGUE  SLIPS. 

United  States.    Dejmrtmetit  of  the  interior.     ( XJ.  S.  geological  survey.) 

Department  of  the  interior  |  —  |  Monograplis  |  of  tlie  |  United 
States  geological  survey  |  Volume  XXIX  |  [Seal  of  the  depart- 
ment] I  Washington  |  government  printing  office  |  1898 

Second  title:  United  States  geological  survey  |  Charles  D. 
Waloott,  director  |  —  |  Geology  |  of  |  OH  Hampshire  Coirnty, 
Massachusetts  |  comprising  |  Franklin,  Hampshire,  and  Hamp- 
den counties  |  by  |  Benjamin  Kendall  Emerson  |  [Vignette]  | 

Washington  |  government  printing  office  |  1898 

4°.    xxi,790pp.   35  pi. 


C  Emeison  (Benjamin  Kendall). 

5  United    States  geological   survey   |    Charles  D.  Walcott,   di- 

-<  rector  |  —  |  Geology  |  of  |  Old  Hampshire  County,  Massachusetts 

I  comprising  |  Franklin,  Hampshire,  and  Hampden  counties  |  hy 
I  Benjamin  Kendall  Emerson  |  [Vignette]  | 
.  Washington  |  government  printing  office  |  1898 

4°.    xxi,  790  pp.    35  pi. 

[tTNrrED  States.    Department  of   the  interior.     (V.  S.  geological  survey.) 
Monograph  XXIX.] 


United   States  geological   survey  |   Charles   D.  Waloott,   di- 
rector I  —  I  Geology  |  of  |  Old  Hampshire  County,  Massachusetts 
I  comprising  |  Franklin,  Hampshire,  and  Hampden  counties  |  by 
I  Benjamin  Kendall  Emerson  |  [Vignette]  | 
Washington  |  government  printing  office  |  1898 

4°.    xxi,  790  pp.    35  pi. 

[TTXTTED  States.    Department  of  the  interior.     (U.  S.  geological  survey.) 
Mouograpb  XXIX.] 


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